Study design: Prospective, cohort study.
Objective: Demonstrate validity of Patient reported outcomes measurement information system (PROMIS) physical function, pain interference, and pain behavior computer adaptive tests (CATs) in surgically treated lumbar stenosis patients.
Summary of background data: There has been increasing attention given to patient reported outcomes associated with spinal interventions. Historical patient outcome measures have inadequate validation, demonstrate floor/ceiling effects, and infrequently used due to time constraints. PROMIS is an adaptive, responsive National Institutes of Health (NIH) assessment tool that measures patient-reported health status.
Methods: Ninety-eight consecutive patients were surgically treated for lumbar spinal stenosis and were assessed using PROMIS CATs, Oswestry disability index (ODI), Zurich Claudication Questionnaire (ZCQ), and Short-Form 12 (SF-12). Prior lumbar surgery, history of scoliosis, cancer, trauma, or infection were excluded. Completion time, preoperative assessment, 6 weeks and 3 months postoperative scores were collected.
Results: At baseline, 49%, 79%, and 81% of patients had PROMIS pain behavior (PB), pain interference (PI), and physical function (PF) scores greater than 1 standard deviation (SD) worse than the general population. 50.6% were categorized as severely disabled, crippled, or bed bound by ODI. PROMIS CATs demonstrated convergent validity through moderate to high correlations with legacy measures (r = 0.35-0.73). PROMIS CATs demonstrated known groups validity when stratified by ODI levels of disability. ODI improvements of at least 10 points on average had changes in PROMIS scores in the expected direction (PI = -12.98, PB = -9.74, PF = 7.53). PROMIS CATs demonstrated comparable responsiveness to change when evaluated against legacy measures. PROMIS PB and PI decreased 6.66 and 9.62 and PROMIS PF increased 6.8 points between baseline and 3-months post-op (P < 0.001). Completion time for the PROMIS CATs (2.6 min) compares favorably to ODI, ZCQ, and SF-12 scores (3.1, 3.6, and 3.0 min).
Conclusion: PROMIS CATs demonstrate convergent validity, known groups validity, and responsiveness for surgically treated patients with lumbar stenosis to detect change over time and are more efficient than legacy instruments.
Level of evidence: 2.