Dataset Information

An approach to exploring patterns of imbalance and potential missingness in reports of the randomized baseline values for primary outcomes measurable at baseline in randomized controlled trials for meta-analyses.

ABSTRACT:

Background

This study evaluated the adequacy of randomization in randomized controlled trials by investigating baseline differences in the primary outcome when a meta-analysis employed an outcome whose baseline level was measurable.

Methods

We retrieved Cochrane reviews published during one year. We calculated the proportion of studies that reported randomized baseline values for the primary outcome. The standardized mean difference (SMD) was used to assess baseline imbalance and heterogeneity. We explored ranking-ordered forest plots using a normal cumulative probability curve as a guideline representing well-performed randomized trials. When skewness was suggested, a funnel plot was drawn to assess whether there was a significant linear trend.

Results

In 10 of 18 meta-analyses, more than 25% of trials did not report randomized baseline values of the primary outcomes. Three meta-analyses indicated baseline imbalance (P < 0.1) and three showed substantial heterogeneity (I² > 60%). Four meta-analyses with forest plots suggesting a skewed SMD distribution also showed a linear trend on their standard errors on the funnel plot.

Conclusions

If the primary outcome is measured at baseline, it is essential to explore the full scope of baseline imbalance among the trials. This could help understand patterns of bias, including missingness, for designing adjustment.

SUBMITTER: Park EG

PROVIDER: S-EPMC9148458 | biostudies-literature | 2022 May

REPOSITORIES: biostudies-literature

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Publications

An approach to exploring patterns of imbalance and potential missingness in reports of the randomized baseline values for primary outcomes measurable at baseline in randomized controlled trials for meta-analyses.

Park Eun-Gee EG Hahn Seokyung S

BMC medical research methodology 20220528 1

<h4>Background</h4>This study evaluated the adequacy of randomization in randomized controlled trials by investigating baseline differences in the primary outcome when a meta-analysis employed an outcome whose baseline level was measurable.<h4>Methods</h4>We retrieved Cochrane reviews published during one year. We calculated the proportion of studies that reported randomized baseline values for the primary outcome. The standardized mean difference (SMD) was used to assess baseline imbalance and ...[more]

PMID: 35643437

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Project description:Rationale: Sex-based differences in pulmonary arterial hypertension (PAH) are known, but the contribution to disease measures is understudied. Objectives: We examined whether sex was associated with baseline 6-minute-walk distance (6MWD), hemodynamics, and functional class. Methods: We conducted a secondary analysis of participant-level data from randomized clinical trials of investigational PAH therapies conducted between 1998 and 2014 and provided by the U.S. Food and Drug Administration. Outcomes were modeled as a function of an interaction between sex and age or sex and body mass index (BMI), respectively, with generalized mixed modeling. Results: We included a total of 6,633 participants from 18 randomized clinical trials. A total of 5,197 (78%) were female, with a mean age of 49.1 years and a mean BMI of 27.0 kg/m2. Among 1,436 males, the mean age was 49.7 years, and the mean BMI was 26.4 kg/m2. The most common etiology of PAH was idiopathic. Females had shorter 6MWD. For every 1 kg/m2 increase in BMI for females, 6MWD decreased 2.3 (1.6-3.0) meters (P < 0.001), whereas 6MWD did not significantly change with BMI in males (0.31 m [-0.30 to 0.92]; P = 0.32). Females had lower right atrial pressure (RAP) and mean pulmonary artery pressure, and higher cardiac index than males (all P < 0.03). Age significantly modified the sex by RAP and mean pulmonary artery pressure relationships. For every 10-year increase in age, RAP was lower in males (0.5 mm Hg [0.3-0.7]; P < 0.001), but not in females (0.13 [-0.03 to 0.28]; P = 0.10). There was a significant decrease in pulmonary vascular resistance (PVR) with increasing age regardless of sex (P < 0.001). For every 1 kg/m2 increase in BMI, there was a 3% decrease in PVR for males (P < 0.001), compared with a 2% decrease in PVR in females (P < 0.001). Conclusions: Sexual dimorphism in subjects enrolled in clinical trials extends to 6MWD and hemodynamics; these relationships are modified by age and BMI. Sex, age, and body size should be considered in the evaluation and interpretation of surrogate outcomes in PAH.

Dataset Information

An approach to exploring patterns of imbalance and potential missingness in reports of the randomized baseline values for primary outcomes measurable at baseline in randomized controlled trials for meta-analyses.

Background

Methods

Results

Conclusions

Publications

An approach to exploring patterns of imbalance and potential missingness in reports of the randomized baseline values for primary outcomes measurable at baseline in randomized controlled trials for meta-analyses.

Similar Datasets

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