| 31. |
- Arbeus, Mikael, et al.
(författare)
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Milrinone Increases Flow in Coronary Artery Bypass Grafts After Cardiopulmonary Bypass : A Prospective, Randomized, Double-Blind, Placebo-Controlled Study
- 2009
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Ingår i: Journal of Cardiothoracic and Vascular Anesthesia. - : Elsevier BV. - 1053-0770 .- 1532-8422. ; 23:1, s. 48-53
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To compare the effects of a bolus of milrinone, 50 mu g/kg, versus placebo on flow in coronary artery bypass grafts after cardiopulmonary bypass (CPB). Design: A prospective, randomized, double-blind study. Setting: A university hospital. Participants: Forty-four patients with stable angina and left ventricular ejection fraction > 30% scheduled for elective coronary artery bypass graft (CABG) surgery were included. Intervention: Patients were randomized to receive 50 mu g/kg of milrinone (n = 22) or placebo (n = 22) after aortic declamping. Measurements and Main Results: The flow in coronary artery bypass grafts was measured with a transit time flow meter at 10 minutes and 30 minutes after termination of CPB. The hemodynamic evaluation included transesophageal echocardiography, mean arterial pressure (MAP), heart rate, and intracavitary measurement of left ventricular end-diastolic pressure (LVEDP). The flow in the saphenous vein grafts was significantly higher in the milrinone group when compared with the placebo group both at 10 and 30 minutes after termination of CPB (p < 0.001). At 10 minutes, the flow was 64.5 +/- 37.4 mL/min (mean +/- standard deviation) and 43.6 +/- 25.7 mL/min in nonsequential vein grafts for milrinone and placebo, respectively. Corresponding values at 30 minutes were 54.8 +/- 29.9 mL/min and 35.3 +/- 22.4 mL/min. The left internal thoracic artery (LITA) flow was higher in the milrinone group but did not reach statistical significance. The fractional area change was higher, and the MAP and calculated pressure gradient (MAP-LVEDP) were lower at 10 minutes in the milrinone group. Conclusion: Milrinone significantly increases the flow in anastomosed saphenous vein grafts after CPB, and has beneficial effects on left ventricular function.
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| 32. |
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| 33. |
- Arvidsson, Bo, 1962-, et al.
(författare)
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Reference data for bone mineral density in Swedish women using digital X-ray radiometry
- 2013
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Ingår i: Journal of clinical densitometry. - New York, USA : Elsevier. - 1094-6950 .- 1559-0747. ; 16:2, s. 183-188
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Tidskriftsartikel (refereegranskat)abstract
- During the last decade, digital X-ray radiometry (DXR) has been used to measure bone mineral density (BMD) in the metacarpal bones. The aim of this study was to establish Swedish reference material for bone mass in women, measured in the metacarpal bones with DXR, and compare these data with the data from the manufacturer. A sample of 1440 women aged 20-79yr living in Örebro County was randomly assigned from the population register. Microdose mammography was used (Sectra MDM L30; Sectra Imtec AB, Linköping, Sweden) to measure BMD. Cole's LMS method was used to calculate DXR. Six hundred sixty-nine (48.3%) women participated. Peak bone mass occurred at the age of 43.4yr with a BMD of 0.597g/cm(2) (standard deviation: 0.050). Our Swedish data correlated well with the manufacturer's material. Only among women aged 50-59yr did BMD differ, where the Swedish sample had lower values. The LMS method can be used to describe the DXR data and provide a more detailed picture of bone density distribution. DXR-BMD in Swedish women aged 20-79yr is equivalent to findings from other studies, showing the same distribution of BMD in most age groups except for ages 50-59yr.
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| 34. |
- Axén, Iben, et al.
(författare)
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Analyzing repeated data collected by mobile phones and frequent text messages : An example of Low back pain measured weekly for 18 weeks
- 2012
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Ingår i: BMC Medical Research Methodology. - : BioMed Central. - 1471-2288. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Background: Repeated data collection is desirable when monitoring fluctuating conditions. Mobile phones can be used to gather such data from large groups of respondents by sending and receiving frequently repeated short questions and answers as text messages.The analysis of repeated data involves some challenges. Vital issues to consider are the within-subject correlation, the between measurement occasion correlation and the presence of missing values.The overall aim of this commentary is to describe different methods of analyzing repeated data. It is meant to give an overview for the clinical researcher in order for complex outcome measures to be interpreted in a clinically meaningful way.Methods: A model data set was formed using data from two clinical studies, where patients with low back pain were followed with weekly text messages for 18 weeks. Different research questions and analytic approaches were illustrated and discussed, as well as the handling of missing data. In the applications the weekly outcome “number of days with pain” was analyzed in relation to the patients’ “previous duration of pain” (categorized as more or less than 30 days in the previous year).Research questions with appropriate analytical methods1: How many days with pain do patients experience? This question was answered with data summaries.2: What is the proportion of participants “recovered” at a specific time point? This question was answered using logistic regression analysis.3: What is the time to recovery? This question was answered using survival analysis, illustrated in Kaplan-Meier curves, Proportional Hazard regression analyses and spline regression analyses.4: How is the repeatedly measured data associated with baseline (predictor) variables? This question was answered using generalized Estimating Equations, Poisson regression and Mixed linear models analyses.5: Are there subgroups of patients with similar courses of pain within the studied population?A visual approach and hierarchical cluster analyses revealed different subgroups using subsets of the model data.Conclusions: We have illustrated several ways of analysing repeated measures with both traditional analytic approaches using standard statistical packages, as well as recently developed statistical methods that will utilize all the vital features inherent in the data.
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| 35. |
- Axén, Iben, et al.
(författare)
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Clustering patients on the basis of their individual course of low back pain over a six month period
- 2011
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Ingår i: BMC Musculoskeletal Disorders. - : BioMed Central. - 1471-2474. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Background: Several researchers have searched for subgroups in the heterogeneous population of patients with non-specific low back pain (LBP). To date, subgroups have been identified based on psychological profiles and the variation of pain.Methods: This multicentre prospective observational study explored the 6- month clinical course with measurements of bothersomeness that were collected from weekly text messages that were sent by 176 patients with LBP. A hierarchical cluster analysis, Ward's method, was used to cluster patients according to the development of their pain.Results: Four clusters with distinctly different clinical courses were described and further validated against clinical baseline variables and outcomes. Cluster 1, a "stable" cluster, where the course was relatively unchanged over time, contained young patients with good self- rated health. Cluster 2, a group of "fast improvers" who were very bothered initially but rapidly improved, consisted of patients who rated their health as relatively poor but experienced the fewest number of days with bothersome pain of all the clusters. Cluster 3 was the "typical patient" group, with medium bothersomeness at baseline and an average improvement over the first 4-5 weeks. Finally, cluster 4 contained the "slow improvers", a group of patients who improved over 12 weeks. This group contained older individuals who had more LBP the previous year and who also experienced most days with bothersome pain of all the clusters.Conclusions: It is possible to define clinically meaningful clusters of patients based on their individual course of LBP over time. Future research should aim to reproduce these clusters in different populations, add further clinical variables to distinguish the clusters and test different treatment strategies for them.
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| 36. |
- Axén, Iben, et al.
(författare)
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Searching for the optimal measuring frequency in longitudinal studies : an example utilizing short message service (SMS) to collect repeated measures among patients with low back pain
- 2016
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Ingår i: BMC Medical Research Methodology. - : BioMed Central. - 1471-2288. ; 16:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Mobile technology has opened opportunities within health care and research to allow for frequent monitoring of patients. This has given rise to detailed longitudinal information and new insights concerning behaviour and development of conditions over time.Responding to frequent questionnaires delivered through mobile technology has also shown good compliance, far exceeding that of traditional paper questionnaires. However, to optimize compliance, the burden on the subjects should be kept at a minimum.In this study, the effect of using fewer data points compared to the full data set was examined, assuming that fewer measurements would lead to better compliance.Method: Weekly text-message responses for 6 months from subjects recovering from an episode of low back pain (LBP) were available for this secondary analysis. Most subjects showed a trajectory with an initial improvement and a steady state thereafter.The data were originally used to subgroup (cluster) patients according to their pain trajectory. The resulting 4-cluster solution was compared with clusters obtained from five datasets with fewer data-points using Kappa agreement as well as inspection of estimated pain trajectories. Further, the relative risk of experiencing a day with bothersome pain was compared week by week to show the effects of discarding some weekly data.Results: One hundred twenty-nine subjects were included in this analysis. Using data from every other weekly measure had the highest agreement with the clusters from the full dataset, weighted Kappa = 0.823. However, the visual description of pain trajectories favoured using the first 18 weekly measurements to fully capture the phases of improvement and steady-state. The weekly relative risks were influenced by the pain trajectories and 18 weeks or every other weekly measure were the optimal designs, next to the full data set.Conclusions: A population recovering from an episode of LBP could be described using every other weekly measurement, an option which requires fewer weekly measures than measuring weekly for 18 weeks. However a higher measuring frequency might be needed in the beginning of a clinical course to fully map the pain trajectories.
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| 37. |
- Axén, Iben, et al.
(författare)
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The Nordic maintenance care program : the clinical use of identified indications for preventive care
- 2013
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Ingår i: Chiropractic and Manual Therapies. - : BioMed Central (BMC). - 2045-709X. ; 21:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Low back pain (LBP) is a prevalent condition and has been found to be recurrent and persistent in a majority of cases. Chiropractors have a preventive strategy, maintenance care (MC), aimed towards minimizing recurrence and progression of such conditions. The indications for recommending MC have been identified in the Nordic countries from hypothetical cases. This study aims to investigate whether these indications are indeed used in the clinical encounter.Methods: Data were collected in a multi-center observational study in which patients consulted a chiropractor for their non-specific LBP. Patient baseline information was a) previous duration of the LBP, b) the presence of previous episodes of LBP and c) early improvement with treatment. The chiropractors were asked if they deemed each individual patient an MC candidate. Logistic regression analyses (uni– and multi-level) were used to investigate the association of the patient variables with the chiropractor’s decision.Results: The results showed that “previous episodes” with LBP was the strongest predictor for recommending MC, and that the presence of all predictors strengthens the frequency of this recommendation. However, there was considerable heterogeneity among the participating chiropractors concerning the recommendation of MC.Conclusions: The study largely confirms the clinical use of the previously identified indications for recommending MC for recurrent and persistent LBP. Previous episodes of LBP was the strongest indicator.
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| 38. |
- Axén, Iben, et al.
(författare)
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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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Ingår i: Journal of Clinical Epidemiology. - : Elsevier. - 0895-4356 .- 1878-5921. ; 65:4, s. 454-461
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Tidskriftsartikel (refereegranskat)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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| 39. |
- Axén, Iben, et al.
(författare)
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Using few and scattered time points for analysis of a variable course of pain can be misleading : an example using weekly text message data
- 2014
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Ingår i: The spine journal. - : Elsevier. - 1529-9430 .- 1878-1632. ; 14:8, s. 1454-1459
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Tidskriftsartikel (refereegranskat)abstract
- Background context: Because low back pain (LBP) is a fluctuating condition, the diversity in the prediction literature may be due to when the outcome is measured.Purpose: The objective of this study was to investigate the prediction of LBP using an outcome measured at several time points.Study design/setting: A multicenter clinical observational study in Sweden.Patient sample: Data were collected on 244 subjects with nonspecific LBP. The mean age of the subjects was 44 years, the mean pain score at inclusion was 4.4/10, and 51% of the sample had experienced LBP for more than 30 days the previous year.Outcome measures: The outcome used in this study was the “number of days with bothersome pain” collected with weekly text messages for 6 months.Methods: In subjects with nonspecific LBP, weekly data were available for secondary analyses. A few baseline variables were chosen to investigate prediction at different time points: pain intensity, the presence of leg pain, duration of LBP the previous year, and self-rated health at baseline. Age and gender acted as additional covariates.Results: In the multilevel models, the predictive variables interacted with time. Thus, the risk of experiencing a day with bothersome LBP varied over time. In the logistic regression analyses, the predictive variable's previous duration showed a consistent predictive ability for all the time points. However, the variables pain intensity, leg pain, and self-rated health showed inconsistent predictive patterns.Conclusions: An outcome based on frequently measured data described the variability in the prediction of future LBP over time. Prediction depended on when the outcome was measured. These results may explain the diversity of the results of the predictor studies in the literature.
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| 40. |
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