Article type
Year
Abstract
Background: Attrition from randomised trials can introduce bias and reduce statistical power affecting the generalizability, validity, and reliability of results. Many strategies are used by researchers to reduce attrition such as motivating and engaging participants and adding sites to generate optimal data return or compliance to follow-up procedures.
Objectives: To quantify the effect of strategies to reduce attrition from randomised trials in any health care setting.
Methods: Included studies were randomised evaluations of strategies to reduce attrition embedded within randomised trials from all diseases and clinical settings. The following sources were searched for eligible studies: MEDLINE (1950 to present), EMBASE (1980 to present), PsycINFO (1806 to present), DARE (most recent issue), CENTRAL (most recent issue), CINAHL (1981 to present), C2-SPECTR (most recent date), and ERIC (1966-present), Cochrane Methodology Register, Current Controlled Trials metaRegister, WHO trials platform, Society for Clinical Trials (SCT) conference proceedings (1980-2010), and publication reference lists. A survey of all UK clinical trials units was conducted to identify ongoing or completed but unreported studies. Data from trials were pooled using the fixed effect model and heterogeneity explored to determine the level of effectiveness of the type of strategies used and the study design to reduce attribution.
Results: From 19,281 abstracts 32 unique RCTs were identified from the following sources: MEDLINE, CENTRAL, CINAHL n = 9; SCT abstracts 1980-2010 n = 4; reference lists of relevant reviews n = 7; and of included trials n = 8 (7 duplicates); reference lists of excluded trials n = 1; word of mouth n =4; survey of CTUs n = 6. Five databases returned no RCTs. Included RCTs evaluated 7 types of strategies to reduce attrition including: communication, questionnaire length, incentives, participant case management, visit frequency, behavioural, and methodological interventions.
Objectives: To quantify the effect of strategies to reduce attrition from randomised trials in any health care setting.
Methods: Included studies were randomised evaluations of strategies to reduce attrition embedded within randomised trials from all diseases and clinical settings. The following sources were searched for eligible studies: MEDLINE (1950 to present), EMBASE (1980 to present), PsycINFO (1806 to present), DARE (most recent issue), CENTRAL (most recent issue), CINAHL (1981 to present), C2-SPECTR (most recent date), and ERIC (1966-present), Cochrane Methodology Register, Current Controlled Trials metaRegister, WHO trials platform, Society for Clinical Trials (SCT) conference proceedings (1980-2010), and publication reference lists. A survey of all UK clinical trials units was conducted to identify ongoing or completed but unreported studies. Data from trials were pooled using the fixed effect model and heterogeneity explored to determine the level of effectiveness of the type of strategies used and the study design to reduce attribution.
Results: From 19,281 abstracts 32 unique RCTs were identified from the following sources: MEDLINE, CENTRAL, CINAHL n = 9; SCT abstracts 1980-2010 n = 4; reference lists of relevant reviews n = 7; and of included trials n = 8 (7 duplicates); reference lists of excluded trials n = 1; word of mouth n =4; survey of CTUs n = 6. Five databases returned no RCTs. Included RCTs evaluated 7 types of strategies to reduce attrition including: communication, questionnaire length, incentives, participant case management, visit frequency, behavioural, and methodological interventions.