Identifying risk of prescription analgesic misuse in chronic pain: screening utility and clinical cut-offs of the Japanese PROMIS Rx Misuse 7a in a low-opioid prescribing environment

Background Most screening tools for prescription analgesic misuse were developed in high-opioid prescribing contexts. This study evaluated the measurement properties and screening utility of the Japanese version of the PROMIS Prescription Pain Medication Misuse–Short Form 7a (PROMIS Rx Misuse 7a) in a strictly regulated, low-opioid prescribing environment. Methodology A cross-sectional web-based survey was conducted among 500 Japanese adults with chronic pain who were currently prescribed analgesics. The sample was randomly divided into an exploratory subsample ( n = 250) and an independent confirmatory subsample ( n = 250). Structural validity was evaluated using exploratory factor analysis (EFA), parallel analysis, confirmatory factor analysis (CFA), and item response theory (IRT). Reliability was assessed using internal consistency and test–retest methods. Construct validity was examined through correlations and structural equation modeling using hypothesis testing based on expected patterns of association. Screening performance was evaluated using receiver operating characteristic analysis, with the Severity of Dependence Scale (SDS) as an external reference criterion for elevated psychological dependence risk. Results Independent-sample EFA, parallel analysis, and CFA supported a predominantly unidimensional structure, although RMSEA remained elevated. Internal consistency was acceptable to good (Cronbach’s α = 0.79; McDonald’s ω = 0.80), whereas test–retest reliability was moderate (ICC = 0.61; 95% bootstrap CI, 0.40–0.78). IRT analysis indicated high discriminative capacity, particularly at moderate-to-high misuse levels. Construct validity was supported by a strong unadjusted correlation with the SDS ( r = 0.58), which remained similar after sociodemographic adjustment in structural equation modeling (residual correlation = 0.59). The scale showed good discriminative performance for identifying dependence risk (area under the curve = 0.833). A candidate cut-off score of ≥ 13, identified by maximizing the Youden index, yielded 82.3% specificity and 68.4% sensitivity. Conclusions The PROMIS Rx Misuse 7a appears to be a promising screening instrument for detecting prescription analgesic misuse in low-opioid settings. A candidate screening cut-off of ≥ 13 may help identify patients who warrant further clinical assessment.