A study published in the Journal of Affective Disorders has outlined the optimal minimally important difference (MID) and severity thresholds for Patient Reported Outcomes Measurement Information Systems (PROMIS) depression scales. These parameters, notably a T-score change of 3 to 4 points for the PROMIS depression scale MID, may be helpful for investigating the effects of treatment on depression.
Kurt Kroenke, MD, from the department of medicine, Indiana University School of Medicine, Indianapolis, and colleagues pooled data from randomized controlled trials with a cohort of 651 patients. The studies included primary care patients with chronic low back pain treated with either medication or cognitive-behavioral therapy, primary care patients with chronic back pain or hip or knee osteoarthritis pain treated with either opioids or nonopioid medications, and survivors of stroke who underwent a stroke self-management program.
Participants in these studies completed the 8-item original short form and the 4-item, 6-item, and 8-item scales of the PROMIS adult profile instruments. The MID was estimated with assessments of correspondence between the PROMIS depression scores and the Patient Health Questionnaire (PHQ-9).
Using the PHQ-9 diagnostic algorithm, the proportion of patients who met Diagnostic and Statistical Manual of Mental Disorders, 5th Edition, criteria for major or minor depression was 58.1%, 24.6%, and 33.7% in the 3 trial samples, respectively. The optimal MID estimate for PROMIS depression scales was 3.5 points; the majority of methods ranged between 3 and 4 points across each of the 3 trials. Each 1-point change in PHQ-9 score correlated with an average PROMIS T-score change of 1.25 points (interquartile range, 1.19-1.32 points). The investigators found that reasonable PROMIS T-score thresholds for mild, moderate, moderately severe, and severe depression were 55, 60, 65, and 70, respectively.
The study was limited by the inclusion of studies comprising mostly men with mild to moderate depression who were treated at Veterans Administration primary clinics. The MID estimates from this study may hold potential for assisting in interpreting research data, guiding clinical decisions, and informing “power calculations for clinical studies,” as the study authors wrote.
Kroenke K, Stump TE, Chen CX, et al. Minimally important differences and severity thresholds are estimated for the PROMIS depression scales from three randomized clinical trials [published online January 23, 2020]. J Affect Disord. doi:10.1016/j.jad.2020.01.101.