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. 2011 Sep;58(3):349-55.
doi: 10.1053/j.ajkd.2011.04.023. Epub 2011 Jul 20.

Loss to analysis in randomized controlled trials in CKD

Aneet Deo  1 , Christopher H Schmid, Amy Earley, Joseph Lau, Katrin Uhlig
Affiliations

Loss to analysis in randomized controlled trials in CKD

Aneet Deo et al. Am J Kidney Dis. 2011 Sep.

Abstract

Background: Nephrology has a limited number of randomized controlled trials (RCTs). The quality of randomized trials is compromised further when not all participants randomly assigned are accounted for transparently.

Objectives: Systematically evaluate RCTs in individuals with chronic kidney disease regarding reporting and accounting of data missing in outcome analysis.

Study design: De novo empirical evaluation.

Setting & population: English-language parallel-group design RCTs in adults with chronic kidney disease on dialysis therapy or with a kidney transplant published in MEDLINE in 2007 and 2008.

Outcomes & measurements: (1) How often was there loss to analysis, defined as not all randomly assigned participants included in primary outcome analysis? (2) How often was intention-to-treat analysis complete; in other words, included all randomly assigned participants in their originally allocated group? (3) How often were methods of data imputation reported?

Results: Of 196 eligible RCTs, 27% did not clearly describe a primary outcome, 5% did not provide numbers of patients randomly assigned and analyzed, and 12% used time-to-event analysis. Of the remaining 110 studies, 58% had some loss to analysis, with a median loss to analysis of 10%. Fifty-four percent of trials claimed to have performed an intention-to-treat analysis, but only 44% of those included all participants randomly assigned. Only 5 of 110 (5%) studies mentioned imputation of missing data.

Limitations: Evaluation is restricted to analysis of primary study outcome. Only English-language publications were included. Exclusion of time-to-event analyses.

Conclusions: In variance to the reporting standards of CONSORT (Consolidated Standards of Reporting Trials), we found primary outcome designation missing in one-fourth of trials and poor quality in reporting and accounting of primary outcome data lost to analysis. Greater attention to transparency in handling and reporting loss to analysis will enhance the quality of trials in individuals with chronic kidney disease.

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Conflict of interest statement

Because an author of this manuscript is an editor for AJKD, the peer-review and decision-making processes were handled entirely by an Associate Editor (Jonathan C. Craig, MD, PhD, MM (Clin Epi), University of Sydney) who served as Acting Editor-in-Chief. Details of the journal’s procedures for potential editor conflicts are given in the Editorial Policies section of the AJKD website.

Figures

Figure 1.
Figure 1.
Study selection. Abbreviations: AKI, acute kidney injury; RCT, randomized controlled trial; UTI, urinary tract infection.
Figure 2.
Figure 2.
Proposed addition to the CONSORT (Consolidated Standards of Reporting Trials) flow diagram. An addition to the analysis section of the CONSORT flow diagram could show the numbers of participants with and without a measured outcome. If participants with a measured outcome are excluded from analysis, the investigator should provide reasons. If participants do not have a measured outcome, the investigators should specify the reasons for lack of a measured outcome and, if participants are included in the analysis, the method of imputation should be described.
See this image and copyright information in PMC

Comment in

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