Review of response rates over time in registry-based studies using patient-reported outcome measures

OBJECTIVES: Gain an overview of expected response rates (RRs) to patient-reported outcome measures (PROMs) in clinical quality registry-based studies and long-term cohorts in order to better evaluate the validity of registries and registry-based studies. Examine the trends of RRs over time and how they vary with study type, questionnaire format, and the use of reminders. DESIGN: Literature review with systematic search. DATA SOURCES: PubMed, MEDLINE, EMBASE, kvalitetsregistre.no, kvalitetsregister.se and sundhed.dk. ELIGIBILITY CRITERIA: Articles in all areas of medical research using registry-based data or cohort design with at least two follow-up time points collecting PROMs and reporting RRs. Annual reports of registries including PROMs that report RRs for at least two time points. PRIMARY OUTCOME MEASURE: RRs to PROMs. RESULTS: A total of 10 articles, 12 registry reports and 6 registry articles were included in the review. The overall RR at baseline was 75%±22.1 but decreased over time. Cohort studies had a markedly better RR (baseline 97%±4.7) compared with registry-based data at all time points (baseline 72%±21.8). For questionnaire formats, paper had the highest RR at 86%±19.4, a mix of electronic and paper had the second highest at 71%±15.1 and the electronic-only format had a substantially lower RR at 42%±8.7. Sending one reminder (82%±16.5) or more than one reminder (76%±20.9) to non-responders resulted in a higher RR than sending no reminders (39%±6.7). CONCLUSIONS: The large variation and downward trend of RRs to PROMs in cohort and registry-based studies are of concern and should be assessed and addressed when using registry data in both research and clinical practice.