Evaluating patient-reported outcome measures (PROMs) for bladder cancer: a systematic review using the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) checklist

Patient-reported outcome measures (PROMs) are important tools used to understand patient-focused outcomes from care. Various PROMs have been developed for patients with bladder cancer (BC), although the disease's heterogeneity makes selection difficult. Accurate measurement of health-related quality of life (HRQL) can only be achieved if the PROM chosen is 'fit for purpose' (i.e. psychometrically sound). Systematic reviews of psychometric properties are useful for selecting the best PROM for a specific purpose. The COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) developed a checklist to improve the selection of health measurement instruments as part of a review process. Our aims were to undertake a systematic review, using the COSMIN criteria, to assess the quality of studies that report the psychometric properties of PROMs used with people with BC and determine the psychometric quality of these PROMs. An electronic search of seven databases including PubMed, MEDLINE and EMBASE (PROSPERO reference CRD42016051974) was undertaken to identify English language publications, published between January 1990 and September 2017 that evaluated psychometric properties of PROMs used in BC research. Two researchers independently screened abstracts and selected full-text papers. Studies were rated on methodological quality using the COSMIN checklist. Overall, 4663 records were screened and 23 studies, reporting outcomes in 3568 patients, were evaluated using the COSMIN checklist. Most PROMs had limited information reported about their psychometric properties. Studies reporting on the Bladder Cancer Index (BCI) and Functional Assessment of Cancer Therapy Vanderbilt Cystectomy Index (FACT-VCI) provided the most detail and these PROMs could be evaluated on the most COSMIN properties. Based on the available evidence, no existing PROM stands out as the most appropriate to measure HRQL in BC populations. This is due to two factors; (i) the heterogeneity of BC and its treatments (ii) no PROM was evaluated on all COSMIN measurement properties due to a lack of validation studies. We suggest future evaluation of generic, cancer generic and BC-specific PROMs to better understand their application with BC populations and propose strategies to help clinicians and researchers.