OBJECTIVE The Patient-Reported Outcomes Measurement Information System (PROMIS) has become increasingly popular due to computer adaptive testing methodology. This study aims to validate the association between PROMIS and legacy outcome metrics and compare PROMIS to legacy metrics in terms of ceiling and floor effects and questionnaire burden. METHODS A retrospective review of an outcomes database was performed at a single institution from December 2016 to April 2017. Inclusion criteria were age > 18 years and a chief complaint of back pain or neck pain. The PROMIS computer adaptive testing Pain Interference, Physical Function (PF), and Pain Intensity domains; Oswestry Disability Index (ODI); Neck Disability Index (NDI); and visual analog scale (VAS) back, VAS leg, VAS neck, and VAS arm were completed in random order. PROMIS was compared to legacy metrics in terms of the average number of questions needed to complete each questionnaire and the score distributions in the lower and higher bounds of scores. RESULTS A total of 494 patients with back pain and 130 patients with neck pain were included. For back pain, ODI showed a strong correlation with PROMIS-PF (R = −0.749, p < 0.001), Pain Intensity (R = 0.709, p < 0.001), and Pain Interference (R = 0.790, p < 0.001) domains. Additionally, the PROMIS Pain Intensity domain correlated to both VAS back and neck pain (R = 0.642, p < 0.001 for both). PROMIS-PF took significantly fewer questions to complete compared to the ODI (4.123 vs 9.906, p < 0.001). When assessing for instrument sensitivity, neither survey presented a significant ceiling and floor effect in the back pain population (ODI: 0.40% and 2.63%; PROMIS-PF: 0.60% and 1.41%). In the neck pain cohort, NDI showed a strong correlation with PROMIS-PF (R = 0.771, p < 0.001). Additionally, PROMIS Pain Intensity correlated to VAS neck (R = 0.642, p < 0.001). The mean number of questions required to complete the questionnaire was much lower for PROMIS-PF compared to NDI (4.417 vs 10, p < 0.001). There were no significant differences found in terms of ceiling and floor effects for neck complaints (NDI: 2.3% and 6.92%; PROMIS-PF: 0.00% and 5.38%) or back complaints (ODI: 0.40% and 2.63%; PROMIS-PF: 1.41% and 0.60%). CONCLUSIONS PROMIS correlates strongly with traditional disability measures in patients with back pain and neck pain. For both back and neck pain, the PROMIS-PF required patients to answer significantly fewer questions to achieve similar granularity. There were no significant differences in ceiling and floor effects for NDI or ODI when compared with the PROMIS-PF instrument.
Keywords: CAT = computer adaptive testing; HRQOL = health-related quality of life; NDI; NDI = Neck Disability Index; Neck Disability Index; ODI; ODI = Oswestry Disability Index; Oswestry Disability Index; PF = Physical Function; PROM = patient-reported outcome measure; PROMIS; PROMIS = Patient-Reported Outcomes Measurement Information System; Patient-Reported Outcomes Measurement Information System; VAS = visual analog scale; back pain; neck pain; patient-reported outcome measures.