Measurement properties of the Chronic Prostatitis Symptom Index (NIH-CPSI): a systematic review

Chronic pelvic pain (CPP) of non-inflammatory origin is termed chronic pelvic pain syndrome (CPPS). It is characterized by persistent pelvic pain in the absence of infection or evident local pathology. In men, CPP is often related to the prostate and may affect urinary, pain, and quality-of-life domains. The Chronic Prostatitis Symptom Index (NIH‑CPSI), developed by the National Institutes of Health, is one of the most widely used patient-reported outcome measures for assessing symptom severity and health-related quality of life in men with CPPS. Despite its widespread use in both clinical practice and research, a comprehensive synthesis of the evidence regarding the measurement properties of the NIH-CPSI remains limited. Evaluating the reliability, validity, responsiveness, and other measurement properties of this instrument is essential to ensure its appropriate use and interpretation in clinical and research contexts. Therefore, the aim of this systematic review is to evaluate the measurement properties of the NIH-CPSI in men with CPP or chronic prostatitis/CPPS. This systematic review will follow the reporting recommendations of the PRISMA and the methodological standards proposed by the COSMIN (COnsensus-based Standards for the selection of health Measurement INstruments). Studies reporting on the development and/or evaluation of one or more measurement properties of the NIH-CPSI will be included. Searches will be conducted in databases including EMBASE, Pubmed, and PsychInfo, complemented by manual searches in Google Scholar. Data extraction and analysis will follow COSMIN criteria, considering methodological quality, risk of bias, and the level of evidence supporting the measurement properties of the NIH-CPSI.