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Moderate concordance was found between case-only and parallel group designs in systematic comparison

Pouwels, K., Mulder, B. & Hak, E., Mar-2016, In : Journal of Clinical Epidemiology. 71, p. 18-24 7 p.

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  • Moderate concordance was found between case-only and parallel group designs in systematic comparison

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Objectives: To empirically evaluate the concordance of effect estimates between case-only and parallel group designs and to identify predictors of discrepancies.

Study Design and Setting: MEDLINE and EMBASE databases were searched through June 31, 2013. Studies that used both a case only (case crossover or self-controlled case series) and a parallel group design (cohort or case-control) were identified. Spearman correlation coefficient was used to evaluate the concordance between designs. Z-scores were used to assess whether differences in the effect estimates were common, using an absolute threshold value of 1.96. A prediction model was built to identify predictors of discrepancies.

Results: The search identified 1,367 articles of which 53 were included for analysis. In total, 519 comparisons were made. The correlation coefficient between case-only vs. parallel group studies was 0.64 (P <.001). In 221 of the 519 comparisons (43%), the difference between both study designs was larger than the predetermined threshold. The following predictors of discrepancy were found: intermittent exposure, rare event, acute outcome, length of hazard period, type of case-only design, and sample size (C statistic of 0.783).

Conclusion: The concordance between effect estimates of case-only and parallel group designs is moderate. Such discrepancies could be predicted by failure to meet assumptions of case-only designs. (C) 2016 Elsevier Inc. All rights reserved.

Original languageEnglish
Pages (from-to)18-24
Number of pages7
JournalJournal of Clinical Epidemiology
Volume71
Publication statusPublished - Mar-2016

    Keywords

  • Case crossover, Self-controlled case series, Research design, Crossover studies, Cohort studies, Case-control studies, SEQUENCE-SYMMETRY-ANALYSIS, URINARY-TRACT-INFECTIONS, CASE-CROSSOVER DESIGN, CASE SERIES, EVENTS, CONFOUNDERS, RISK

ID: 24339876