Using PROMIS Pain Interference Items to Improve Quality Measurement in Inpatient Rehabilitation Facilities

Abstract

Objective: To evaluate the Patient-Reported Outcomes Measurement Information System (PROMIS) pain interference items for use in a quality measure and to compare the resulting quality score, along with internal reliability and validity, to a similar item set in the Minimum Data Set Version 3.0 (MDS).

Design: Cross-sectional, observational study.

Setting: One freestanding inpatient rehabilitation facility (IRF) and one large hospital-based IRF.

Participants: Patients with neurologic disorders. Of 1055 consecutive admissions, 26% were excluded based on clinician-determined cognitive impairment or emotional distress. Of the remainder, 50% consented and completed the survey near the end of their IRF stay (N = 391). Of these, more than half (57%) reported pain over the last day (n = 224).

Measurements: Psychometric statistics and quality scores were computed from a 55-question survey, including the MDS and PROMIS pain interference items.

Results: Estimates for internal reliability were higher for the PROMIS 2-item scale compared to the MDS: Cronbach α (0.86 vs 0.48) and interitem correlations (0.75 vs 0.31). The PROMIS-2 items were better able to detect differences in patients with mild and severe pain intensity (Cohen d = 1.57) relative to the corresponding MDS items (Cohen d = 0.81). Two quality scores based on the PROMIS-2 items, reflecting low and high levels of pain interference, showed 46% or 12% of patients meeting these thresholds. This compared to a 30% rate when patients were classified by the MDS as experiencing pain interference.

Conclusions: PROMIS pain interference items appear to be more internally consistent than similar MDS items. The graded PROMIS items permit the creation of multiple quality scores, showing predictable overlap with corresponding MDS quality scores. Because PROMIS items provide finer distinctions, they allow greater latitude in reporting quality scores. We recommend further study of pain interference scores across IRFs to improve their reliability and validity.

Keywords: PROMIS; Patient-reported outcomes; assessment; minimum data set; pain interference; quality metrics.