| 1. |
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| 2. |
- Ahl, Rebecka, 1987-, et al.
(author)
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Effects of beta-blocker therapy on mortality after elective colon cancer surgery : a Swedish nationwide cohort study
- 2020
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In: BMJ Open. - : BMJ Publishing Group Ltd. - 2044-6055. ; 10:7
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Journal article (peer-reviewed)abstract
- OBJECTIVE: Colon cancer surgery remains associated with substantial postoperative morbidity and mortality despite advances in surgical techniques and care. The trauma of surgery triggers adrenergic hyperactivation which drives adverse stress responses. We hypothesised that outcome benefits are gained by reducing the effects of hyperadrenergic activity with beta-blocker therapy in patients undergoing colon cancer surgery. This study aims to test this hypothesis.DESIGN: Retrospective cohort study.SETTING AND PARTICIPANTS: This is a nationwide study which includes all adult patients undergoing elective colon cancer surgery in Sweden over 10 years. Patient data were collected from the Swedish Colorectal Cancer Registry. The national drugs registry was used to obtain information about beta-blocker use. Patients were subdivided into exposed and unexposed groups. The association between beta-blockade, short-term and long-term mortality was evaluated using Poisson regression, Kaplan-Meier curves and Cox regression.PRIMARY AND SECONDARY OUTCOMES: Primary outcome of interest was 1-year all-cause mortality. Secondary outcomes included 90-day all-cause and 5-year cancer-specific mortality.RESULTS: The study included 22 337 patients of whom 36.1% were prescribed preoperative beta-blockers. Survival was higher in patients on beta-blockers up to 1 year after surgery despite this group being significantly older and of higher comorbidity. Regression analysis demonstrated significant reductions in 90-day deaths (IRR 0.29, 95% CI 0.24 to 0.35, p<0.001) and a 43% risk reduction in 1-year all-cause mortality (adjusted HR 0.57, 95% CI 0.52 to 0.63, p<0.001) in beta-blocked patients. In addition, cancer-specific mortality up to 5 years after surgery was reduced in beta-blocked patients (adjusted HR 0.80, 95% CI 0.73 to 0.88, p<0.001).CONCLUSION: Preoperative beta-blockade is associated with significant reductions in postoperative short-term and long-term mortality following elective colon cancer surgery. Its potential prophylactic effect warrants further interventional studies to determine whether beta-blockade can be used as a way of improving outcomes for this patient group.
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| 3. |
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| 4. |
- Ali, Fathalla, 1963-, et al.
(author)
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Effect of the SARS-CoV-2 pandemic on planned and emergency hernia repair in Sweden : a register-based study
- 2023
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In: Hernia. - : Springer. - 1265-4906 .- 1248-9204. ; 27:5, s. 1103-1108
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Journal article (peer-reviewed)abstract
- PURPOSE: The COVID-19 has had a profound impact on the health care delivery in Sweden, including deprioritization of benign surgeries during the COVID-19 pandemic. The aim of this study was to assess the effect of COVID-19 pandemic on emergency and planned hernia repair in Sweden.METHODS: Data on hernia repairs from January 2016 to December 2021 were retrieved from the Swedish Patient Register using procedural codes. Two groups were formed: COVID-19 group (January 2020-December 2021) and control group (January 2016-December 2019). Demographic data on mean age, gender, and type of hernia were collected.RESULTS: This study showed a weak negative correlation between the number of elective hernia repairs performed each month during the pandemic and the number of emergency repairs carried out during the following 3 months for inguinal hernia repair (p = 0.114) and incisional hernia repair (p = 0.193), whereas there was no correlation for femoral or umbilical hernia repairs.CONCLUSION: The COVID-19 pandemic had a great impact on planned hernia surgeries in Sweden, but our hypothesis that postponing planned repairs would increase the risk of emergency events was not supported.
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| 5. |
- Ali, Fathalla, 1963-, et al.
(author)
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Peritoneal Bridging Versus Nonclosure in Laparoscopic Ventral Hernia Repair
- 2023
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In: Annals of Surgery Open. - : Wolters Kluwer. - 2691-3593. ; 4:1
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Journal article (peer-reviewed)abstract
- Introduction: Postoperative seroma and pain are common problems following laparoscopic intraperitoneal onlay mesh (IPOM) repair of ventral hernias. These advers outcomes may be avoided by dissecting and using the peritoneum in the hernial sac to bridge the hernia defect.Methods: This was a patient- an and outcome assesor-blinded, parallel-design, randomized controlled trial compairing nonclosure and peritoeal bridging approaches in patients schedueled for elective midline ventral hernia repair. The primary end point was seroma volume on ultrasonography. The secondary end points were postoperative pain, recurrence, and complications.Results: Between November 2018 and December 2020, 112 patients were randomized of whom 60 were in the nonclosure group and 52 were in the peritoneal bridging group. The seroma volume in the nonclosure and peritoneal bridging groups were 17cm3(6-53cm3) versus 0cm3(0-26cm3) at 1-moth follow-up (P=0.013). The median volume was zero at 3-, 6-, and 12-month follow-ups in both groups. No significant differences were observed in early postoperative pain (P=0.447) and in recurrencerate (P=0.684). There were 4(7%) and 1(2%) perioperative complictions that lead to reoperations in simple IPOM(sIPOM) and IPOM with peritoneal bridging (IPOM-pb), respectively.Conclusion: Seroma was less prevalent after IPOM-pb at 1-month follow-up compaired with sIPOM, with simillar posoperative pain 1 week after index of surgery in both groups. At subsequent follow-ups, the differences in seroma were not statiscally significant. Further studies are required to confirm these results. Trial registration (NCT04229940)Keywords: epigastric hernia, incisional hernia, IPOM with fascia closure, IPOM with peritoneal bridging, laparoscopic hernia repair, simple IPOM, umblical hernia, ventral hernia
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| 6. |
- Altıntaş, Özge, et al.
(author)
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Equality of admission tests using kernel equating under the non-equivalent groups with covariates design
- 2021
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In: International Journal of Assessment Tools in Education. - : International Journal of Assessment Tools in Education. - 2148-7456. ; 8:4, s. 729-743
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Journal article (peer-reviewed)abstract
- Educational assessment tests are designed to measure the same psychological constructs over extended periods of time. This feature is important considering that test results are often used in the selection process for admittance to university programs. To ensure fair assessments, especially for those whose results weigh heavily in selection decisions, it is necessary to collect evidence demonstrating that the assessments are not biased, and to confirm that the scores obtained from different test forms have statistical equality. For this purpose, test equating has important functions, as it prevents bias generated by differences in the difficulty levels of different test forms, allows the scores obtained from different test forms to be reported on the same scale, and ensures that the reported scores communicate the same meaning. In this study, these important functions were evaluated using real college admission test data from different test administrations. The kernel equating method under the non-equivalent groups with covariates design was applied to determine whether the scores obtained from different time periods but measuring the same psychological constructs were statistically equivalent. The non-equivalent groups with covariates design was specifically used because the test groups of the admission test are non-equivalent and there are no anchor items. Results from the analyses showed that the test forms had different score distributions, and that the relationship was non-linear. The equating procedure was thus adjusted to eliminate these differences and thereby allow the tests to be used interchangeably.
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| 7. |
- Calissendorff, Jan, et al.
(author)
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Long-Term Outcome of Graves' Disease : A Gender Perspective
- 2023
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In: Women's Health Reports. - : Mary Ann Liebert. - 2688-4844. ; 4:1, s. 487-496
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Journal article (peer-reviewed)abstract
- Introduction: In gender-skewed conditions such as Graves' disease (GD), the outcome naturally becomes dominated by the majority. This may lead to gender-biased misunderstandings regarding treatment outcomes. This especially holds true when complications, such as depression, are unevenly distributed. We have, therefore, studied the long-term outcome of GD from a gender perspective.Materials and Methods: A cohort of 1186 patients with GD was included in a follow-up 6-10 years after inclusion. Choice of treatment, the feeling of recovery, long-term treatment, comorbidity, and quality of life were investigated with questionnaires. All results were studied sex-divided.Results: We included 973 women and 213 men. There was no difference between men and women in the choice of treatment. At follow-up, women scored significantly worse in the general questionnaire 36-item Short-Form Health Status (SF-36) domain bodily pain and in the thyroid-specific Thyroid-Related Patient-Reported Outcome (ThyPRO) domains depression, impaired sex life, and cosmetic complaints, all p < 0.05. Women were twice as likely (29.5%) to be treated with levothyroxine after successful treatment with antithyroid drugs (ATD) compared with men (14.9%, p < 0.05).Conclusion: After treatment for GD, women were more affected by depression, impaired sex life, cosmetic issues, and bodily pain despite successful cure of hyperthyroidism. The prevalence of hypothyroidism was also doubled in women. Whether these observed gender differences reflect a worse outcome of GD in women or a natural consequence of a higher prevalence of these symptoms and autoimmunity in the female population is difficult to disentangle. Nevertheless, several years after GD, women reveal more persistent symptoms.
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| 8. |
- Holmberg, M., et al.
(author)
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Treatment outcome 6-10 years after diagnosis of hyperthyroidism in 2916 patients : a longitudinal evaluation of a swedish incidence cohort
- 2018
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In: Thyroid. - : Mary Ann Liebert. - 1050-7256 .- 1557-9077. ; :S1
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Journal article (other academic/artistic)abstract
- Treatment of Graves’ disease (GD) and toxic nodular goiter (TNG) has the objectives to cure hyperthyroidism, prevent recurrent disease and preserve thyroid function. Treatment efficacies and long-termout comes of antithyroid drugs (ATD), radioactive iodine (RAI) or surgery varies in the literature. We report outcome of treatment, cure rate and risk factors for relapse for GD and TNG in an unselected cohort. A prospective incidence-cohort of de novo diagnosed GD and TNG patients (n = 2916) from 2003-05, were invited to a follow-up 6 - 10 years after diagnosis. Questionnaires were sent to 2430 patients regarding treatments, cure rate, recurrence, quality of life, demographic data, comorbidities and life-style factors. Patients were treated according to clinical routine with ATD, RAI or surgery. Of those included, 1186 (83.3%) had GD and 237 (16.7%) had TNG. In GD patients, 351 (45.3%), 264 (81.5%), and 52 (96.3%) were cured by ATD, RAI or surgery respectively as first line treatment. Of those, 77.0%, 15.4% and 3.8% respectively were without levothyr-oxine supplementation at follow-up at 8 – 0.9 years. Including all treatment modalities, 851 (71.8%) of GD patients were cured within one treatment period. At follow-up, 278 (23%) of GD patients had been operated. In TNG patients, RAI cured 88.6% and surgery 92.9%, whereof 52/154 (33.8%) and 3/15 (20%) had no levothyroxine supplementation post RAI and surgery, respectively.The proportion that did not feel fully recovered at follow-up was 25.3% of GD and 18.1% of the TNG patients. Overall, treatment of hyperthyroidism results in preserved thyroid function only in 35.3% and 44.7% of GD and TNG cases, respectively. As many as 23.4% of the GD patients end up with surgery although only 4.6% choose it from the beginning. Our treatment tradition cures 71.8% of GD patients and 78.1% of TNG patients within one treatment period. The high number of patients who do not feel recovered 6 -10 years after hyperthyroidism in GD and TNG is are minder of the chronic nature of hyperthyroidism.
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| 9. |
- Khamisi, Selwan, et al.
(author)
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Fracture Incidence in Graves' Disease: A Population-Based Study.
- 2023
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In: Thyroid : official journal of the American Thyroid Association. - : Mary Ann Liebert. - 1557-9077 .- 1050-7256. ; 33:11, s. 1349-1357
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Journal article (peer-reviewed)abstract
- Background: Population-based studies have indicated an increase in bone turnover in hyperthyroidism with a subsequent decrease in bone mineral density and an increased risk of fractures, especially in postmenopausal women. However, heterogeneity between studies prevents a definitive conclusion. Graves' disease (GD) is an autoimmune disease, and it is the most common cause of hyperthyroidism. The aim of this study was to investigate fracture risk in patients with GD. Methods: A total of 2134 patients with incident GD and 21,261 age, sex- and county-matched controls were included 16-18 years after diagnosis in a retrospective cohort study. Drug and patient national registries in Sweden were used to assess the risk of developing skeletal complications. Up to 10 years of age, sex- and county-matched controls per patient were selected from databases from the National Board of Health and Welfare and Statistics Sweden. Cox proportional hazards models were fitted to estimate hazard ratios (HR) and confidence intervals [CI]. Results: There were no significant differences in fracture rates between GD and controls but after adjustment for comorbidities, the data showed higher vertebral fracture rates in male GD patients aged >52 years compared to male controls, HR=2.83 [CI 1.05-7.64]. The rates of osteoporosis treatments as well as treatment with corticosteroids were higher in patients with GD. However, HR for the association between GD and fractures remained largely unchanged after adjustment for osteoporosis treatments and treatments with corticosteroids. Conclusions: There were no significant differences in total fracture rate between GD and the general population. However, men older than 52 years had a higher vertebral fracture rate. This study also shows that patients with treated GD receive more osteoporosis treatments compared to the general population.
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| 10. |
- Liu, Xinyi, et al.
(author)
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Rotation to sparse loadings using Lp losses and related inference problems
- 2023
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In: Psychometrika. - : Springer. - 0033-3123 .- 1860-0980. ; 88, s. 527-553
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Journal article (peer-reviewed)abstract
- Researchers have widely used exploratory factor analysis (EFA) to learn the latent structure underlying multivariate data. Rotation and regularised estimation are two classes of methods in EFA that they often use to find interpretable loading matrices. In this paper, we propose a new family of oblique rotations based on component-wise Lp loss functions (0<p≤1)(0<p≤1) that is closely related to an Lp regularised estimator. We develop model selection and post-selection inference procedures based on the proposed rotation method. When the true loading matrix is sparse, the proposed method tends to outperform traditional rotation and regularised estimation methods in terms of statistical accuracy and computational cost. Since the proposed loss functions are nonsmooth, we develop an iteratively reweighted gradient projection algorithm for solving the optimisation problem. We also develop theoretical results that establish the statistical consistency of the estimation, model selection, and post-selection inference. We evaluate the proposed method and compare it with regularised estimation and traditional rotation methods via simulation studies. We further illustrate it using an application to the Big Five personality assessment.
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| 11. |
- Pironi, Loris, et al.
(author)
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Characteristics of adult patients with chronic intestinal failure due to short bowel syndrome: An international multicenter survey
- 2021
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In: Clinical Nutrition ESPEN. - : Elsevier BV. - 2405-4577. ; 45, s. 433-441
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Journal article (peer-reviewed)abstract
- Background and aims: The case-mix of patients with intestinal failure due to short bowel syndrome (SBS-IF) can differ among centres and may also be affected by the timeframe of data collection. Therefore, the ESPEN international multicenter cross-sectional survey was analyzed to compare the characteristics of SBS-IF cohorts collected within the same timeframe in different countries. Methods: The study included 1880 adult SBS-IF patients collected in 2015 by 65 centres from 22 countries. The demographic, nutritional, SBS type (end jejunostomy, SBS-J; jejuno-colic anastomosis, SBS-JC; jejunoileal anastomosis with an intact colon and ileocecal valve, SBS-JIC), underlying disease and intravenous supplementation (IVS) characteristics were analyzed. IVS was classified as fluid and electrolyte alone (FE) or parenteral nutrition admixture (PN). The mean daily IVS volume, calculated on a weekly basis, was categorized as <1, 1–2, 2–3 and >3 L/day. Results: In the entire group: 60.7% were females and SBS-J comprised 60% of cases, while mesenteric ischaemia (MI) and Crohn’ disease (CD) were the main underlying diseases. IVS dependency was longer than 3 years in around 50% of cases; IVS was infused ≥5 days/week in 75% and FE in 10% of cases. Within the SBS-IF cohort: CD was twice and thrice more frequent in SBS-J than SBS-JC and SBS-JIC, respectively, while MI was more frequent in SBS-JC and SBS-JIC. Within countries: SBS-J represented 75% or more of patients in UK and Denmark and 50-60% in the other countries, except Poland where SBS-JC prevailed. CD was the main underlying disease in UK, USA, Denmark and The Netherlands, while MI prevailed in France, Italy and Poland. Conclusions: SBS-IF type is primarily determined by the underlying disease, with significant variation between countries. These novel data will be useful for planning and managing both clinical activity and research studies on SBS.
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| 12. |
- Sj?lin, G., et al.
(author)
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The Long-Term Outcome of Treatment for Graves' Hyperthyroidism
- 2019
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In: Thyroid. - : Mary Ann Liebert Inc. - 1050-7256 .- 1557-9077. ; 29:11, s. 1545-1557
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Journal article (peer-reviewed)abstract
- Background: The treatment efficacy of antithyroid drug (ATD) therapy, radioactive iodine (I-131), or surgery for Graves' hyperthyroidism is well described. However, there are a few reports on the long-term total outcome of each treatment modality regarding how many require levothyroxine supplementation, the need of thyroid ablation, or the individual patient's estimation of their recovery. Methods: We conducted a pragmatic trial to determine the effectiveness and adverse outcome in a patient cohort newly diagnosed with Graves' hyperthyroidism between 2003 and 2005 (n = 2430). The patients were invited to participate in a longitudinal study spanning 8 +/- 0.9 years (mean +/- standard deviation) after diagnosis. We were able to follow 1186 (60%) patients who had been treated with ATD, I-131, or surgery. We determined the mode of treatment, remission rate, recurrence, quality of life, demographic data, comorbidities, and lifestyle factors through questionnaires and a review of the individual's medical history records. Results: At follow-up, the remission rate after first-line treatment choice with ATD was 45.3% (351/774), with I-131 therapy 81.5% (324/264), and with surgery 96.3% (52/54). Among those patients who had a second course of ATD, 29.4% achieved remission (vs. the 45.3% after the first course of ATD). The total number of patients who had undergone ablative treatment was 64.3% (763/1186), of whom 23% (278/1186) had received surgery, 43% (505/1186) had received I-131 therapy, including 2% (20/1186) who had received both surgery and I-131. Patients who received ATD as first-line treatment and possibly additional ATD had 49.7% risk (385/774) of having undergone ablative treatment at follow-up. Levothyroxine replacement was needed in 23% (81/351) of the initially ATD treated in remission, in 77.3% (204/264) of the I-131 treated, and in 96.2% (50/52) of the surgically treated patients. Taken together after 6-10 years, and all treatment considered, normal thyroid hormone status without thyroxine supplementation was only achieved in 35.7% (423/1186) of all patients and in only 40.3% of those initially treated with ATD. The proportion of patients that did not feel fully recovered at follow-up was 25.3%. Conclusion: A patient selecting ATD therapy as the initial approach in the treatment of Graves' hyperthyroidism should be informed that they have only a 50.3% chance of ultimately avoiding ablative treatment and only a 40% chance of eventually being euthyroid without thyroid medication. Surprisingly, 1 in 4 patients did not feel fully recovered after 6-10 years. The treatment for Graves' hyperthyroidism, thus, has unexpected long-term consequences for many patients.
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| 13. |
- Sjölin, Gabriel, 1979-
(author)
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Hyperthyroidism : a chronic disease?
- 2021
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Doctoral thesis (other academic/artistic)abstract
- During 2003-2005, approximately 3,000 de novo hyperthyroid patients were collected in Sweden and became one of the world's largest hyperthyroidism studies. This dissertation shows that many people diagnosed with hyperthyroidism live with its impacts even after excess of thyroid hormone has ended. These include repeated recurrences, multiple treatments, replacement therapy, little sense of recovery, and reduced Quality Of life(QoL). Patients were categorised into two groups, Graves' disease (GD) and toxic nodular goitre (TNG), studied separately. Overall, just over 1,400 patients, or 60% of dispatches, answered the questionnaires. 1186 GD, 237 TNG. Most patients were women and GD's mean age was around 40 years, while TNG patients were 20 years older, reflecting the same patternas previous studies. The incidence of 27/100,000 persons per year might not seem large, but considering the proposed chronic nature of hyperthyroidism, prevalence is high (0.7%). Around two in three people diagnosed with hyperthyroidism will live with thyroid hormone replacement. This could be attributed, that GD patients over time receive more ablative treatment, despite the fact that less receive it as the first treatment. Another explanation the recurrence risk of ATD-treated patients exceeds 50%. Levothyroxine treatment did not vary between TNG treatments. Repeated, often multiple, treatments in TNG patients are rarely described. This implies TNG may be more complex than anticipated. Hyperthyroid patients have worse QoL 6-10 years following diagnosis than the general public. RAI treated patients with GD had more affected long-term thyroid-specific and generic QoL than ATD and surgical patients. Surprisingly, there was no clear QoL difference between GD and TNG. GD is often seen as a severe condition than TNG, as TNG has a milder course of disease. Hyperthyroidism has long-term impacts, affecting a relatively large population. This dissertation's findings indicate a chronic nature of hyperthyroidism.
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| 14. |
- Sjölin, Gabriel, 1979-, et al.
(author)
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Long term outcome after toxic nodular goitre
- 2022
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In: Thyroid Research. - : Springer Science and Business Media LLC. - 1756-6614. ; 15:1
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Journal article (peer-reviewed)abstract
- Background: The purpose of treating toxic nodular goitre (TNG) is to reverse hyperthyroidism, prevent recurrent disease, relieve symptoms and preserve thyroid function. Treatment efficacies and long-term outcomes of antithyroid drugs (ATD), radioactive iodine (RAI) or surgery vary in the literature. Symptoms often persist for a long time following euthyroidism, and previous studies have demonstrated long-term cognitive and quality of life (QoL) impairments. We report the outcome of treatment, rate of cure (euthyroidism and hypothyroidism), and QoL in an unselected TNG cohort. Methods: TNG patients (n = 638) de novo diagnosed between 2003-2005 were invited to engage in a 6-10-year follow-up study. 237 patients responded to questionnaires about therapies, demographics, comorbidities, and quality of life (ThyPRO). Patients received ATD, RAI, or surgery according clinical guidelines. Results: The fraction of patients cured with one RAI treatment was 89%, and 93% in patients treated with surgery. The rate of levothyroxine supplementation for RAI and surgery, at the end of the study period, was 58% respectively 64%. Approximately 5% of the patients needed three or more RAI treatments to be cured. The patients had worse thyroid-related QoL scores, in a broad spectrum, than the general population. Conclusion: One advantage of treating TNG with RAI over surgery might be lost due to the seemingly similar incidence of hypothyroidism. The need for up to five treatments is rarely described and indicates that the treatment of TNG can be more complex than expected. This circumstance and the long-term QoL impairments are reminders of the chronic nature of hyperthyroidism from TNG.
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| 15. |
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| 16. |
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| 17. |
- Sjölin, Gabriel, 1979-, et al.
(author)
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Treatment of patients with Graves' disease in Sweden compared to international surveys of an 'index patient'
- 2021
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In: Endocrinology, Diabetes & Metabolism. - : Wiley. - 2398-9238. ; 4:3
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Journal article (peer-reviewed)abstract
- Introduction The treatment strategies for a 42-year-old female index patient with moderate Graves' disease (GD) vary according to several international surveys. The important question whether surveys of treatment preferences in theoretical patient cases also match how real patients are treated has not yet been addressed. Materials and Methods From a Swedish cohort of 1186 GD patients (TT-12 cohort), 27 women were identified using the same criteria as from the index patient surveys from the European and American Thyroid Associations. This 'index patient cohort' was age 40-45, otherwise healthy female, with two children and uncomplicated GD. The applied first-line treatment of the patients in the index cohort, together with its variations, was compared with the treatment preferences according to international surveys. A comparison with the TT-12 cohort was also performed. Results In the 'Index cohort', 77.8% were treated with antithyroid drugs (ATD), and 22.2% were treated with radioiodine (I-131). This preference for ATD is in line with most countries/regions, with the exception of USA and the Middle East/North Africa, where I-131 was preferred. The distribution of treatment in the TT-12 cohort did not significantly differ from the index cohort. ATD was the preferred treatment in male and young (age 19-22) patients, as was RAI in old (age 69-73) patients. The age-related, but not the gender-related, cases differed significantly from the entire TT-12 cohort. Conclusion The treatment choice in an index patient in Sweden seems in line with European practice, where ATD is the preferred first choice. This differs compared to US and North African survey intentions, where I-131 is more often used. Age more than gender influences the treatment choice of GD patients. This is, to our best knowledge, the first time an index patient from 'real life' has been presented and compared to treatment preferences of international thyroid association surveys.
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| 18. |
- Törring, Ove, et al.
(author)
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Impaired Quality of Life After Radioiodine Therapy Compared to Antithyroid Drugs or Surgical Treatment for Graves’ Hyperthyroidism : A Long-Term Follow-Up with the Thyroid-Related Patient-Reported Outcome Questionnaire and 36-Item Short Form Health Status Survey
- 2019
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In: Thyroid. - : Mary Ann Liebert. - 1050-7256 .- 1557-9077. ; 29:3, s. 322-331
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Journal article (peer-reviewed)abstract
- BACKGROUND: Hyperthyroidism is known to have a significant impact on the quality of life (QoL) at least in the short term. The purpose of the present study was to assess QoL in patients at 6-10 years after treatment for Graves' disease (GD) with radioiodine (RAI) to those treated with thyroidectomy or antithyroid drugs (ATD) as assessed with both a thyroid-specific (ThyPRO) and general (SF-36) QoL surveys.METHODS: We evaluated 1186 GD patients in a sub-cohort from an incidence study 2003-2005 which had been treated according to routine clinical practice at seven participating centers. Patients were included if they had returned the ThyPRO (n=975) and/or the SF-36 questionnaire (n=964) and informed consent at follow-up. Scores from ThyPRO were compared with scores from a general population sample (n=712), using multiple linear regression adjusting for age and gender as well as multiple testing. Treatment related QoL outcome for ATD, RAI and surgery were compared including adjustment for the number of treatments received, sex, age and co-morbidity.RESULTS: Regardless of treatment modality, patients with GD had worse thyroid-related QoL 6-10 years after diagnosis compared with the general population. Patients treated with RAI had worse thyroid-related and general QoL than patients treated with ATD or thyroidectomy on the majority of QoL-scales. Sensitivity analyses supported the relative negative comparative effects of RAI treatment on QoL in patients with hyperthyroidism.CONCLUSIONS: Graves' disease is associated with a lower QoL many years after treatment compared to the general population. In a previous, small RCT we did not show any difference in patient satisfaction years after ATD, RAI or surgery. We now report that in a large non-randomized cohort, patients who received RAI had adverse scores on ThyPRO and SF-36. These findings in a Swedish population are limited by comparison to normative data from Denmark, by older age and possibly a more prolonged course in those patients who received radioiodine, and a lack of information regarding thyroid status at the time of evaluation. The way RAI may adversely affect QoL is unknown but since the results may be important for future considerations regarding treatment options for GD they need to be substantiated in further studies.
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| 19. |
- Wallin, Gabriel, et al.
(author)
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Equating nonequivalent groups using propensity scores : model misspecification and sensitivity analysis
- 2021
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In: Quantitative psychology. - Cham : Springer. - 9783030747718 - 9783030747725 ; , s. 187-197
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Book chapter (peer-reviewed)abstract
- Equating test scores from nonequivalent groups requires to separate the effect of differences in ability from differences in test form difficulty between the test forms. The gold standard for this purpose is to use common items, however, not all testing programs have such items available. There might be other useful information available, and this paper studies the use of covariates in equating as a substitute for common items. To gain further insight about how to best incorporate covariates inequating this paper studies the propensity score, a scalar function of the covariates. The sensitivity of the propensity score as a proxy for ability is studied to investigate if bias is introduced in the estimated equated scores if the propensity score estimation model is misspecified. By considering an incorrect link function, leaving out a covariate and leaving out a second-order term from the estimation model, common misspecifications are studied. The results show that equating with respect to the propensity score is relatively robust to model misspecification, especially modeling nonlinearity with a linear model and leaving out second-order terms.
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| 20. |
- Wallin, Gabriel, 1991-
(author)
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Extensions of the kernel method of test score equating
- 2019
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Doctoral thesis (other academic/artistic)abstract
- This thesis makes contributions within the area of test score equating and specifically kernel equating. The first paper of this thesis studies the estimation of the test score distributions needed in kernel equating. There are currently two families of models implemented within kernel equating for this purpose, namely log-linear models and item response theory models. The impact of model selection criteria for these models on the equated scores are studied using both empirical and simulated data.The second paper focuses on the continuization of the estimated score distributions, where different bandwidth selection methods are studied. The study considers multiple data collection designs, sample sizes and score distributions and investigates how large impact the bandwidth selection has on the equated scores.When the test groups differ in their ability distributions it is necessary to adjust for such differences to make fair comparisons possible. The most common way of adjusting for ability imbalance is by using items that are common for both test forms, known as anchor items. If no such items are available, it has been suggested to use background information about the test-takers instead. However, when the covariate vector of background information increases, the combination of covariates with no observations tends to increase as well. The third paper of this thesis therefore suggests to transform the covariate vector into a scalar propensity score. Two equating estimators are suggested under this setting and the standard error of equating (SEE) for both estimators are given.The SEE for kernel equating has previously been derived using the delta method. The fourth paper revisits the Bahadur representation of sample quantiles to derive the SEE. Both methods of calculating the SEE are compared, and it is shown that they are equivalent for all common data collection designs when the terms of the Bahadur SEE are estimated using Taylor expansions. An implementation of an alternative estimator of the Bahadur SEE for which the equivalence result does not hold is also included to illustrate when the two methods differ.
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| 21. |
- Wallin, Gabriel, et al.
(author)
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How Important is the Choice of Bandwidth in Kernel Equating?
- 2021
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In: Applied psychological measurement. - : Sage Publications. - 0146-6216 .- 1552-3497. ; 45:7-8, s. 518-535
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Journal article (peer-reviewed)abstract
- Kernel equating uses kernel smoothing techniques to continuize the discrete score distributions when equating test scores from an assessment test. The degree of smoothness of the continuous approximations is determined by the bandwidth. Four bandwidth selection methods are currently available for kernel equating, but no thorough comparison has been made between these methods. The overall aim is to compare these four methods together with two additional methods based on cross-validation in a simulation study. Both equivalent and non-equivalent group designs are used and the number of test takers, test length, and score distributions are all varied. The results show that sample size and test length are important factors for equating accuracy and precision. However, all bandwidth selection methods perform similarly with regards to the mean squared error and the differences in terms of equated scores are small, suggesting that the choice of bandwidth is not critical. The different bandwidth selection methods are also illustrated using real testing data from a college admissions test. Practical implications of the results from the simulation study and the empirical study are discussed.
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| 22. |
- Wallin, Gabriel, et al.
(author)
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How to select the bandwidth in kernel equating : an evaluation of five different methods
- 2018
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In: Quantitative psychology. - Cham, Switzerland : Springer. - 9783319772486 - 9783319772493 ; , s. 91-100
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Book chapter (peer-reviewed)abstract
- When using kernel equating to equate two test forms, a bandwidth needs to be selected. The bandwidth parameter determines the smoothness of the continuized score distributions and has been shown to have a large effect on the kernel density estimate. There are a number of suggested criteria for selecting the bandwidth, and currently four of them have been implemented in kernel equating. In this paper, all four of the existing bandwidth selectors suggested for kernel equating are evaluated and compared against each other using real test data together with a new criterion that implements leave-one-out cross-validation. Although the bandwidth methods generally were similar in terms of equated scores, there were potentially important differences in the upper part of the score scale where critical admission decisions are typically made.
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| 23. |
- Wallin, Gabriel, et al.
(author)
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Kernel Equating Using Propensity Scores for Nonequivalent Groups
- 2019
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In: Journal of educational and behavioral statistics. - : Sage Publications. - 1076-9986 .- 1935-1054. ; 44:4, s. 390-414
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Journal article (peer-reviewed)abstract
- When equating two test forms, the equated scores will be biased if the test groups differ in ability. To adjust for the ability imbalance between nonequivalent groups, a set of common items is often used. When no common items are available, it has been suggested to use covariates correlated with the test scores instead. In this article, we reduce the covariates to a propensity score and equate the test forms with respect to this score. The propensity score is incorporated within the kernel equating framework using poststratification and chained equating. The methods are evaluated using real college admissions test data and through a simulation study. The results show that propensity scores give an increased equating precision in comparison with the equivalent groups design and a smaller mean squared error than by using the covariates directly. Practical implications are also discussed.
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| 24. |
- Wallin, Gabriel, et al.
(author)
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Model misspecification and robustness of observed-score test equating using propensity scores
- 2023
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In: Journal of educational and behavioral statistics. - : Sage Publications. - 1076-9986 .- 1935-1054. ; 48:5, s. 603-635
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Journal article (peer-reviewed)abstract
- This study explores the usefulness of covariates on equating test scores from nonequivalent test groups. The covariates are captured by an estimated propensity score, which is used as a proxy for latent ability to balance the test groups. The objective is to assess the sensitivity of the equated scores to various misspecifications in the propensity score model. The study assumes a parametric form of the propensity score and evaluates the effects of various misspecification scenarios on equating error. The results, based on both simulated and real testing data, show that (1) omitting an important covariate leads to biased estimates of the equated scores, (2) misspecifying a nonlinear relationship between the covariates and test scores increases the equating standard error in the tails of the score distributions, and (3) the equating estimators are robust against omitting a second-order term as well as using an incorrect link function in the propensity score estimation model. The findings demonstrate that auxiliary information is beneficial for test score equating in complex settings. However, it also sheds light on the challenge of making fair comparisons between nonequivalent test groups in the absence of common items. The study identifies scenarios, where equating performance is acceptable and problematic, provides practical guidelines, and identifies areas for further investigation.
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| 25. |
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| 26. |
- Wallin, Gabriel, et al.
(author)
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Nonequivalent groups with covariates design using propensity scores for kernel equating
- 2017
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In: Quantitative Psychology. - Cham : Springer. - 9783319562933 - 9783319562940 ; , s. 309-319
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Conference paper (peer-reviewed)abstract
- In test score equating, the non-equivalent groups with covariates (NEC) design uses covariates with high correlation to the test scores as a substitute for an anchor test when the latter is lacking. However, as the number of covariates increases, the number of observations for each covariate combination decreases. We suggest to use propensity scores instead, which we include in the kernel equating framework using both post-stratification and chained equating. The two approaches are illustrated with data from a large scale assessment, and the results show an increased precision in comparison with the equivalent groups design, and great similarities in comparison with the results when using an anchor test.
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| 27. |
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| 28. |
- Wallin, Gabriel, et al.
(author)
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Selecting a presmoothing model in kernel equating
- 2020
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In: Quantitative psychology. - New York : Springer. - 9783030434687 - 9783030434694 ; , s. 111-120
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Book chapter (peer-reviewed)abstract
- In the kernel method of test score equating, the first step of the procedure is to presmooth the score distributions. The most common way of doing so is by fitting a log-linear model to the observed-score distributions. In this way, irregularities in the score distributions are smoothed, yielding a more stable estimated equating transformation. Within the kernel equating framework, an alternative way of presmoothing by using item response theory models has recently been suggested. There are furthermore several model selection criteria available for both of these classes of models. Here the model selection criteria are studied for both log-linear and item response theory models. Specifically, the likelihood ratio, AIC, and BIC measures are compared using real admissions data. Results show that the different model selection criteria result in equated scores that have real impact differences.
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