Psychometric assessment of PROMIS-29 as a measure of health status after metabolic and bariatric surgery: a prospective cohort study.

BACKGROUND: Patient-Reported Outcomes Measurement Information System (PROMIS) 29 may be a valuable questionnaire to assess patient-reported outcomes after metabolic and bariatric surgery (MBS), but its psychometric properties in this context remain unclear. OBJECTIVES: To assess the internal consistency, construct validity, and responsiveness of PROMIS-29 as a measure of recovery and longer-term outcomes after MBS. SETTING: Two university hospitals and a private surgical clinic in Canada. METHODS: Patients undergoing laparoscopic MBS completed the PROMIS-29 preoperatively, during the recovery period (postoperative weeks 1, 2, 3, and 4), and longer-term follow-up (postoperative months 6 and 12). Physical Health Summary (PHS) score and Mental Health Summary (MHS) score were derived from T-scores. Internal consistency was appraised using Cronbach's alpha. Construct validity and responsiveness were assessed via a priori hypotheses targeting known-group differences and expected postoperative health trajectories. Each measurement property was deemed acceptable if ≥ 75% hypotheses were confirmed. RESULTS: 351 patients were included (age 44 ± 11, body mass index 45 ± 8, 77% female, 71% sleeve gastrectomy). Internal consistency of PHS and MHS was acceptable (alpha > .7). Construct validity during recovery was limited (PHS 3/8 [38%] and MHS 4/8 [50%] hypotheses confirmed). In the longer term, construct validity was not supported (PHS 0/6 and MHS 0/4). Responsiveness of PHS and MHS was limited in the recovery period (1/4 [25%]) but supported in the longer term (2/2 [100%]). CONCLUSIONS: PROMIS-29 scores were responsive to long-term health improvements after MBS but failed to differentiate groups that were expected to have distinct outcomes. Context-specific tools may be better suited to capture health trajectories post-MBS.