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Association of run-in periods with weight loss in obesity randomized controlled trials.

ABSTRACT: Study-level design characteristics that inform the optimal design of obesity randomized controlled trials (RCTs) have been examined in few studies. A pre-randomization run-in period is one such design element that may influence weight loss. We examined 311 obesity RCTs published between 1 January 2007 and 1 July 2009 that examine d weight loss or weight gain prevention as a primary or secondary end-point. Variables included run-in period, pre-post intervention weight loss, study duration (time), intervention type, percent female and degree of obesity. Linear regression was used to estimate weight loss as a function of (i) run-in (yes/no) and (ii) run-in, time, percent female, body mass index and intervention type. Interaction terms were also examined. Approximately 19% (18.6%) of the studies included a run-in period, with pharmaceutical studies having the highest frequency. Although all intervention types were associated with weight loss (Mean = 2.80 kg, SD = 3.52), the inclusion of a pre-randomization run-in was associated with less weight loss (P = 0.0017) compared with studies that did not include a run-in period. However, this association was not consistent across intervention types. Our results imply that in trials primarily targeting weight loss in adults, run-in periods may not be beneficial for improving weight loss outcomes in interventions.

SUBMITTER: Affuso O

PROVIDER: S-EPMC3885242 | biostudies-literature | 2014 Jan

REPOSITORIES: biostudies-literature

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Association of run-in periods with weight loss in obesity randomized controlled trials.

Affuso O O Kaiser K A KA Carson T L TL Ingram K H KH Schwiers M M Robertson H H Abbas F F Allison D B DB

Obesity reviews : an official journal of the International Association for the Study of Obesity 20130930 1

Study-level design characteristics that inform the optimal design of obesity randomized controlled trials (RCTs) have been examined in few studies. A pre-randomization run-in period is one such design element that may influence weight loss. We examined 311 obesity RCTs published between 1 January 2007 and 1 July 2009 that examine d weight loss or weight gain prevention as a primary or secondary end-point. Variables included run-in period, pre-post intervention weight loss, study duration (time), ...[more]

PMID: 24118736

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Project description:BackgroundEarly identification of participants at risk of run-in failure (RIF) may present opportunities to improve trial efficiency and generalizability.MethodsWe conducted a partial factorial-design, randomized, controlled trial of calcium and vitamin D to prevent colorectal adenoma recurrence at 11 centers in the United States. At baseline, participants completed two self-administered questionnaires (SAQs) and a questionnaire administered by staff. Participants in the full factorial randomization (calcium, vitamin D, both, or neither) received a placebo during a 3-month single-blinded run-in; women electing to take calcium enrolled in a two-group randomization (calcium with vitamin D, or calcium alone) and received calcium during the run-in. Using logistic regression models, we examined baseline factors associated with RIF in three subgroups: men (N = 1606) and women (N = 301) in the full factorial randomization and women in the two-group randomization (N = 666).ResultsOverall, 314/2573 (12 %) participants failed run-in; 211 (67 %) took fewer than 80 % of their tablets (poor adherence), and 103 (33 %) withdrew or were uncooperative. In multivariable models, 8- to 13-fold variation was seen by study center in odds of RIF risk in the two largest groups. In men, RIF decreased with age (adjusted odds ratio [OR] per 5 years 0.85 [95 % confidence interval, CI; 0.76-0.96]) and was associated with being single (OR 1.65 [95 % CI; 1.10-2.47]), not graduating from high school (OR 2.77 [95 % CI; 1.58-4.85]), and missing SAQ data (OR 1.97 [1.40-2.76]). Among women, RIF was associated primarily with health-related factors; RIF risk was lower with higher physical health score (OR 0.73 [95 % CI; 0.62-0.86]) and baseline multivitamin use (OR 0.44 [95 % CI; 0.26-0.75]). Women in the 5-year colonoscopy surveillance interval were at greater risk of RIF than those with 3-year follow-up (OR 1.91 [95 % CI; 1.08-3.37]), and the number of prescription medicines taken was also positively correlated with RIF (p = 0.03). Perceived toxicities during run-in were associated with 12- to 29-fold significantly increased odds of RIF.ConclusionsThere were few common baseline predictors of run-in failure in the three randomization groups. However, heterogeneity in run-in failure associated with study center, and missing SAQ data reflect potential opportunities for intervention to improve trial efficiency and retention.Trial registrationClinicalTrials.gov: NCT00153816 . Registered September 2005.

Project description:OBJECTIVES:To identify geriatric obesity interventions that can guide clinical recommendations. DESIGN:Systematic review using Medline (PubMed), Cochrane Central Register of Controlled Trials, Web of Science, CINAHL, EMBASE (Ovid), and PsycINFO (Proquest) from January 1, 2005, to October 12, 2015, to identify English-language randomized controlled trials. PARTICIPANTS:Individuals aged 60 and older (mean age ?65) and classified as having obesity (body mass index ?30 kg/m2 ). INTERVENTIONS:Behavioral weight loss interventions not involving pharmacological or procedural therapies lasting 6 months or longer. MEASUREMENTS:Two investigators performed the systematic review using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria and achieved a high concordance rate (97.3%) in summarizing the primary outcomes. The three primary outcomes were weight loss, physical performance, and quality of life. RESULTS:Of 5,741 citations, 19 were included. (Six studies were unique, and the remaining 13 were based on the same study population.) Duration ranged from 6 to 18 months (n = 405 participants, age range 66.7-71.1). Weight loss in the intervention groups ranged from 0.5 to 10.7 kg (0.1-9.3%). Five studies had a resistance exercise program accompanying a dietary component. Greater weight loss was observed in groups with a dietary component than those with exercise alone. Exercise alone led to better physical function but no significant weight loss. Combined dietary and exercise components led to the greatest improvement in physical performance measures and quality of life and mitigated reductions in muscle and bone mass observed in diet-only study arms. Heterogeneous outcomes were observed, which limited the ability to synthesize the data quantitatively. CONCLUSIONS:The evidence supporting geriatric obesity interventions to improve physical function and quality of life is of low to moderate quality. Well-designed trials are needed in this population.

Project description:Background: Asthma and obesity are major public health problems, affecting hundreds of millions of people worldwide. Obesity is associated with increased asthma risk and severity, and lower asthma-related quality of life. Objective: In this systematic review, we aimed to evaluate whether weight loss in subjects with obesity and asthma leads to improvement in asthma-related outcomes. Data Sources and Extraction: We searched PubMed and Google Scholar for all studies in English published January 2000-December 2018. Studies were included if they were randomized, controlled clinical trials (RCTs) for overweight/obese children or adults with asthma, with sufficient data to assess outcomes and study quality. Non-randomized and non-controlled studies were excluded, as well as those in subjects without overweight/obesity, or with non-asthmatic controls. Synthesis: We identified four RCTs involving children (total n = 246) and six involving adults (n = 502). All interventions were designed for weight loss and varied from dietary restrictions to multifactorial interventions with exercise training and cognitive behavioral therapy; the duration of intervention ranged from 8 weeks to 18 months. All RCTs reported successful improvements in weight or body mass index (-0.14 standard deviation scores to -15.9% BMI reduction in children, 1.8%-14.5% weight loss in adults). RCTs generally reported improvements in asthma-related quality of life and, to some degree, asthma control. RCTs involving adults also reported improvements in lung function (FEV1, FVC, TLC), while RCTs in children showed less consistent results. Conclusions: These findings suggest that weight loss in subjects with obesity and asthma may improve asthma outcomes. However, there was wide variability in populations studied, baseline and post-intervention assessments, follow-up length, outcome definition and reporting, and statistical approaches, which hindered the ability to compare studies, perform a pooled analysis, or assess generalizability. Primary Source of Funding: U.S. National Institutes of Health (NIH).

Project description:ImportanceSingle-blind placebo run-in (PRI) periods are common in randomized clinical trials (RCTs) of treatment for depression. They aim to increase sensitivity to detect drug effects; however, the association of PRI periods with study outcomes remains unclear. This is concerning given the costs of PRI periods to patients and investigators.ObjectiveTo examine the association of the use of PRI periods with the placebo response, drug response, and drug-placebo difference among RCTs of antidepressants.Data sourcesMEDLINE, Embase, the Cochrane Central Register of Controlled Trials, and PsycINFO, as well as repositories of unpublished studies, were systematically searched up to July 2021.Study selectionIncluded studies were double-blind, placebo-controlled RCTs of antidepressant medication among adults with depressive disorders.Data extraction and synthesisData were extracted into a coding sheet, including the characteristics of studies, the characteristics of PRI periods, and the outcomes of studies.Main outcomes and measuresStudy outcomes were the primary depression symptom measure reported by the RCT. These outcomes were used to calculate effect sizes (Hedges g) of the within-group drug response and placebo response as well as the drug-placebo difference. Random-effects meta-analysis was used to calculate effect sizes, and subgroup analyses were used to compare outcomes depending on use of PRI periods.ResultsA total of 347 trials (representing 89 183 participants) were included; 174 studies (50%) reported using a single-blind PRI period. Response outcome data were available for 189 studies. Studies using PRI periods reported a smaller placebo response (g = 1.05 [95% CI, 0.98-1.11]; I2 = 82%) than studies that did not use a PRI period (g = 1.15 [95% CI, 1.09-1.21]; I2 = 81%; P = .02). Subgroup analysis showed a larger drug response size among studies that did not use a PRI period (g = 1.55 [95% CI, 1.49-1.61]; I2 = 85%) than those that did use a PRI period (g = 1.42 [95% CI, 1.36-1.48]; I2 = 81%; P = .001). The drug-placebo difference did not differ by use of PRI periods (g = 0.33 [95% CI, 0.29-0.38]; I2 = 47% for use of a PRI period vs g = 0.34 [95% CI, 0.30-0.38]; I2 = 54% for no use of PRI periods; P = .92). The likelihood of response to drug vs placebo also did not differ between studies that used a PRI period (odds ratio, 1.89 [95% CI, 1.76-2.03]) and those that did not use a PRI period (odds ratio, 1.77 [95% CI, 1.65-1.89]; P = .18).Conclusions and relevanceThis study suggests that RCTs using PRI periods yield smaller within-group changes across both placebo and drug groups compared with RCTs without PRI periods. The reduction in effect size across groups was equivalent in magnitude. Consequently, PRI studies do not observe larger drug-placebo differences, suggesting that they do not increase trial sensitivity. As such, given the resources and probable deception required and risk to external validity, the practice of using PRI periods in RCTs of antidepressants should be ended.

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Association of run-in periods with weight loss in obesity randomized controlled trials.

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Association of run-in periods with weight loss in obesity randomized controlled trials.

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