| 1. |
- Aerts, Marc, et al.
(author)
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Pooled individual patient data from five countries were used to derive a clinical prediction rule for coronary artery disease in primary care.
- 2017
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In: Journal of Clinical Epidemiology. - : Elsevier. - 0895-4356 .- 1878-5921. ; 81, s. 120-128
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Journal article (peer-reviewed)abstract
- OBJECTIVE: To construct a clinical prediction rule for coronary artery disease (CAD) presenting with chest pain in primary care.STUDY DESIGN AND SETTING: Meta-Analysis using 3,099 patients from five studies. To identify candidate predictors, we used random forest trees, multiple imputation of missing values, and logistic regression within individual studies. To generate a prediction rule on the pooled data, we applied a regression model that took account of the differing standard data sets collected by the five studies.RESULTS: The most parsimonious rule included six equally weighted predictors: age ≥55 (males) or ≥65 (females) (+1); attending physician suspected a serious diagnosis (+1); history of CAD (+1); pain brought on by exertion (+1); pain feels like "pressure" (+1); pain reproducible by palpation (-1). CAD was considered absent if the prediction score is <2. The area under the ROC curve was 0.84. We applied this rule to a study setting with a CAD prevalence of 13.2% using a prediction score cutoff of <2 (i.e., -1, 0, or +1). When the score was <2, the probability of CAD was 2.1% (95% CI: 1.1-3.9%); when the score was ≥ 2, it was 43.0% (95% CI: 35.8-50.4%).CONCLUSIONS: Clinical prediction rules are a key strategy for individualizing care. Large data sets based on electronic health records from diverse sites create opportunities for improving their internal and external validity. Our patient-level meta-analysis from five primary care sites should improve external validity. Our strategy for addressing site-to-site systematic variation in missing data should improve internal validity. Using principles derived from decision theory, we also discuss the problem of setting the cutoff prediction score for taking action.
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| 2. |
- Agüero-Torres, Hedda, et al.
(author)
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Institutionalization in the elderly : The role of chronic diseases and dementia. Cross-sectional and longitudinal data from a population-based study
- 2001
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In: Journal of Clinical Epidemiology. - : Elsevier. - 0895-4356 .- 1878-5921. ; 54:8, s. 795-801
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Journal article (peer-reviewed)abstract
- A population-based study of 1810 persons, aged 75+, was investigated to evaluate the role of dementia and other chronic diseases as determinants of institutionalization in the elderly. The study population was examined at baseline and after a 3-year interval. After adjustment for sociodemographic characteristics, functional dependence, dementia, cerebrovascular disease and hip fracture were associated with living in an institution at baseline. Additionally, functional dependence, hip fracture and dementia were also associated with moving to an institution during the 3-year follow-up. In a similar analysis, including only nondemented subjects, the Mini-Mental State Examination emerged as one of the strongest determinants. The population attributable risk percentage of institutionalization during the 3-year follow-up due to dementia was 61%. This study confirms that dementia and cognitive impairment are the main contributors to institutionalization in the elderly, independently of their sociodemographic status, social network, or functional status.
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| 3. |
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| 4. |
- Anttila, Sten, et al.
(author)
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Conclusiveness resolves the conflict between quality of evidence and imprecision in GRADE
- 2016
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In: Journal of Clinical Epidemiology. - : Elsevier BV. - 1878-5921 .- 0895-4356. ; 2016:75, s. 1-5
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Journal article (peer-reviewed)abstract
- The objective of our article is to show how “quality of evidence” and “imprecision,” as they are defined in Grading of Recommendations Assessment, Development, and Evaluation (GRADE) articles, may lead to confusion. We focus only on the context of systematic reviews.
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| 5. |
- Axén, Iben, et al.
(author)
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The use of weekly text messaging over 6 months was a feasible method for monitoring the clinical course of low back pain in patients seeking chiropractic care
- 2012
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In: Journal of Clinical Epidemiology. - : Elsevier. - 0895-4356 .- 1878-5921. ; 65:4, s. 454-461
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Journal article (peer-reviewed)abstract
- Objective: This study critically evaluates a new method of collecting frequent data using mobile phones and text messages. Fluctuating conditions such as low back pain (LBP) need frequent monitoring to describe the clinical course in detail and to account for individual and subgroup variations.Study Design and Setting: In this multicentre prospective observational study, 262 subjects with nonspecific LBP were followed with weekly text messages for 6 months, with the question “How many days this previous week has your low back pain been bothersome?” The text replies were instantly recorded in a data file to be merged with baseline and follow up data (age, gender, pain intensity, duration, and self- rated health) collected through ordinary questionnaires. The response rate, user-friendliness, and compliance of this method were evaluated.Results: The mean response rate for the text messages throughout the study was 82.5% and was unaffected by season. The method was found to be user friendly. Dropout was not affected by age and gender, but compliance was possibly somewhat affected by outcome.Conclusion: Weekly text messages are a useful method of data collection to examine the clinical course of LBP in the primary care sector.
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| 6. |
- Axfors, Cathrine, et al.
(author)
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Published registry-based pharmacoepidemiologic associations show limited concordance with agnostic medication-wide analyses
- 2023
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In: Journal of Clinical Epidemiology. - : Elsevier BV. - 0895-4356 .- 1878-5921. ; 160, s. 33-45
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Journal article (peer-reviewed)abstract
- Objectives: To assess how the results of published national registry-based pharmacoepidemiology studies (where select associations are of interest) compare with an agnostic medication-wide approach (where all possible drug associations are tested).Study Design and Setting: We systematically searched for publications that reported drug associations with any, breast, colon/colorectal, or prostate cancer in the Swedish Prescribed Drug Registry. Results were compared against a previously performed agnostic medication-wide study on the same registry. Protocol: https://osf.io/kqj8n.Results: Most published studies (25/32) investigated previously reported associations. 421/913 (46%) associations had statistically significant results. 134 of the 162 unique drug-cancer associations could be paired with 70 associations in the agnostic study (corresponding drug categories and cancer types). Published studies reported smaller effect sizes and absolute effect sizes than the agnostic study, and generally used more adjustments. Agnostic analyses were less likely to report statistically significant protective associations (based on a multiplicity-corrected threshold) than their paired associations in published studies (McNemar odds ratio 0.13, P = 0.0022). Among 162 published associations, 36 (22%) showed increased risk signal and 25 (15%) protective signal at P < 0.05, while for agnostic associations, 237 (11%) showed increased risk signal and 108 (5%) protective signal at a multiplicity-corrected threshold. Associations belonging to drug categories targeted by individual published studies vs. nontargeted had smaller average effect sizes; smaller P values; and more frequent risk signals.Conclusion: Published pharmacoepidemiology studies using a national registry addressed mostly previously proposed associations, were mostly “negative”, and showed only modest concordance with their respective agnostic analyses in the same registry.
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| 7. |
- Barbateskovic, Marija, et al.
(author)
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A new tool to assess Clinical Diversity In Meta-analyses (CDIM) of interventions
- 2021
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In: Journal of Clinical Epidemiology. - : Elsevier BV. - 0895-4356 .- 1878-5921. ; 135, s. 29-41
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Journal article (peer-reviewed)abstract
- Objective: To develop and validate Clinical Diversity In Meta-analyses (CDIM), a new tool for assessing clinical diversity between trials in meta-analyses of interventions. Study design and setting: The development of CDIM was based on consensus work informed by empirical literature and expertise. We drafted the CDIM tool, refined it, and validated CDIM for interrater scale reliability and agreement in three groups. Results: CDIM measures clinical diversity on a scale that includes four domains with 11 items overall: setting (time of conduct/country development status/units type); population (age, sex, patient inclusion criteria/baseline disease severity, comorbidities); interventions (intervention intensity/strength/duration of intervention, timing, control intervention, cointerventions); and outcome (definition of outcome, timing of outcome assessment). The CDIM is completed in two steps: first two authors independently assess clinical diversity in the four domains. Second, after agreeing upon scores of individual items a consensus score is achieved. Interrater scale reliability and agreement ranged from moderate to almost perfect depending on the type of raters. Conclusion: CDIM is the first tool developed for assessing clinical diversity in meta-analyses of interventions. We found CDIM to be a reliable tool for assessing clinical diversity among trials in meta-analysis.
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| 8. |
- Bendtsen, Marcus, 1982-, et al.
(author)
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Causal models accounted for research participation effects when estimating effects in a behavioral intervention trial
- 2021
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In: Journal of Clinical Epidemiology. - : Elsevier. - 0895-4356 .- 1878-5921. ; 136, s. 77-83
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Journal article (peer-reviewed)abstract
- Objective Participants in intervention studies are asked to take part in activities linked to the conduct of research, including signing consent forms and being assessed. If participants are affected by such activities through mechanisms by which the intervention is intended to work, then there is confounding. We examine how to account for research participation effects analytically.Study design and setting Data from a trial of a brief alcohol intervention among Swedish university students is used to show how a proposed causal model can account for assessment effects.Results The proposed model can account for research participation effects as long as researchers are willing to use existing data to make assumptions about causal influences, for instance on the magnitude of assessment effects. The model can incorporate several research processes which may introduce bias.Conclusions As our knowledge grows about research participation effects, we may move away from asking if participants are affected by study design, toward rather asking by how much they are affected, by which activities and in which circumstances. The analytic perspective adopted here avoids assuming there are no research participation effects.
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| 9. |
- Björk, Jonas, et al.
(author)
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Risk predictions for individual patients from logistic regression were visualized with bar-line charts.
- 2012
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In: Journal of Clinical Epidemiology. - : Elsevier BV. - 1878-5921 .- 0895-4356. ; 65, s. 335-342
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Journal article (peer-reviewed)abstract
- OBJECTIVE: The interface of a computerized decision support system is crucial for its acceptance among end users. We demonstrate how combined bar-line charts can be used to visualize predictions for individual patients from logistic regression models. STUDY DESIGN AND SETTING: Data from a previous diagnostic study aiming at predicting the immediate risk of acute coronary syndrome (ACS) among 634 patients presenting to an emergency department with chest pain were used. Risk predictions from the logistic regression model were presented for four hypothetical patients in bar-line charts with bars representing empirical Bayes adjusted likelihood ratios (LRs) and the line representing the estimated probability of ACS, sequentially updated from left to right after assessment of each risk factor. RESULTS: Two patients had similar low risk for ACS but quite different risk profiles according to the bar-line charts. Such differences in risk profiles could not be detected from the estimated ACS risk alone. The bar-line charts also highlighted important but counteracted risk factors in cases where the overall LR was less informative (close to one). CONCLUSION: The proposed graphical technique conveys additional information from the logistic model that can be important for correct diagnosis and classification of patients and appropriate medical management.
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| 10. |
- Björk, Jonas, et al.
(author)
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Variability in diagnostic accuracy can be estimated using simple population weighting.
- 2009
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In: Journal of Clinical Epidemiology. - : Elsevier BV. - 1878-5921 .- 0895-4356. ; 62:1, s. 54-57
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Journal article (peer-reviewed)abstract
- OBJECTIVE: Diagnostic accuracy of a quantitative diagnostic test at a given numeric cutoff is dependent on the type of population (e.g., chronic, referrals, or screening) under investigation. Simple weighted averages calculated from a single study sample may be used to assess variability in accuracy in different types of populations. STUDY DESIGN AND SETTING: We evaluated the accuracy of the 4-variable Modification of Diet in Renal Disease (MDRD) Study equation as a diagnostic test to separate stage 1 and 2 chronic kidney disease (>or=60 mL/min per 1.73 m(2)) from stage 3-5 (<60 mL/min per 1.73 m(2) requiring treatment to prevent progression) in a sample of 850 patients referred for determination of glomerular filtration rate (GFR). Using population weighting, we also estimated the accuracy of the MDRD equation when the GFR distribution typically found in screening situations was mimicked. RESULTS: Estimated diagnostic accuracy of the MDRD equation varied substantially for different population types (sensitivity range 82%-97%, specificity 67%-93%; figures include the original MDRD study). CONCLUSIONS: Reports of diagnostic accuracy should include estimates of the variability of diagnostic accuracy, using different real or tentative population distributions. Population weighting is a useful tool for this purpose.
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