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.