Comparative responsiveness of the PROMIS-29 and SF-36 instruments in individuals with chronic musculoskeletal pain.

Background: Chronic musculoskeletal pain (CMP) impacts Health-Related Quality of Life (HRQoL). Several questionnaires are widely used for evaluating the HRQoL, such as Patient Reported Outcomes Measurement Information System 29-item Health Profile (PROMIS-29) and 36-Item Short Form Health Survey (SF-36). This study aimed to assess and compare the responsiveness of PROMIS-29 and SF-36 in individuals with CMP.

Methods: The prospective study collected data from 215 patients with CMP. The participants completed both questionnaires at baseline and a 4-week follow-up with the global perceived effect (GPE) scale. The internal and external responsiveness methods evaluated the responsiveness of the instruments. The effect size (ES) and standardized response mean (SRM) assessed the internal responsiveness. External responsiveness was measured by Spearman's correlation coefficients (r) and area under the receiver operating curve (AUC). The responsiveness of the PROMIS-29 and SF-36 were compared in similar constructs.

Results: The PROMIS-29 demonstrated responsiveness as moderate in fatigue (ES = -0.79, SRM = -0.64), moderate to large in pain interference (ES = -0.94, SRM = -0.64), and large effect in pain intensity subscale (ES = -1.25, SRM = -1.16). The SF-36 bodily pain exhibited moderate responsiveness (ES = 0.73, SRM = 0.60). Spearman's correlation showed moderate between GPE and change scores of PROMIS-29 physical function (r = 0.31), fatigue (r = -0.36), pain intensity (r = 0.45), and weak between GPE and changes score of SF-36 (r = 0.15-0.26). Besides, the AUC of the PROMIS-29 fatigue, and pain intensity scale were 0.701 and 0.725, respectively, indicating superior discriminative ability.

Conclusions: The PROMIS-29 and SF-36 were the most responsive in assessing the pain domain for physical health and PROMIS-29 fatigue domain for mental health among individuals with CMP. The PROMIS-29 demonstrated superior results compared to the SF-36. Other domains related to HRQoL could be considered in other assessment instruments.