Composite measures of pain, anxiety, and depressive (PAD) symptoms: Construct and predictive validity.

Objective: Pain, anxiety, and depression (PAD) are common, co-occurring symptoms that adversely affect one another and may respond to common treatments. PAD composite measures would be useful for tracking treatment response in patients with PAD symptoms. The goal of this study is to compare 3 different PAD composite scales in terms of construct validity, responsiveness, and utility in predicting global improvement.

Method: The sample consisted of 294 primary care patients enrolled in a telecare trial for treating pain, anxiety, and depression. Assessments at baseline and 3 months included the Brief Pain Inventory, PHQ-9 depression scale, GAD-7 anxiety scale, PROMIS measures, Medical Outcomes Study Short-Form items, disability measures, and patient-reported global improvement. Construct validity of the PAD composite measures, their responsiveness, and their ability to predict global improvement was analyzed using Pearson correlations, standardized response means, and receiver operating characteristics analysis.

Results: PAD composite measures correlated strongly with one another, and moderately with measures of function, vitality, and disability. Each PAD composite measure demonstrated similar responsiveness in detecting improvement at 3 months as assessed by standardized response means (SRMs) and area under the curve (AUC analyses).The SRMs for partial and substantial global improvement corresponded to moderate (Cohen's d of 0.58 to 0.69) and large (0.81 to 0.93) effect sizes, respectively.

Conclusions: Three different PAD composite measures demonstrate good construct validity as well as responsiveness in detecting global improvement of pain, anxiety and depression at 3 months.