To determine the efficacy of an internet-based cognitive-behavioral therapy (iCBT) program for depression in older adults with osteoarthritis (OA) of the knee and comorbid major depressive disorder (MDD).
We conducted a randomized controlled trial in 69 adults (ages ≥50 years) meeting criteria for MDD and OA of the knee with 1-week postintervention (week 11) and 3-month followup (week 24) end points. Patients were allocated to either a 10-week iCBT program for depression added to treatment as usual (TAU) or to a TAU control group. Primary outcomes were depression symptoms (9-Item Patient Health Questionnaire [PHQ-9]) and psychological distress (Kessler-10 [K-10]). Secondary outcomes included arthritis self-efficacy (Arthritis Self-Efficacy Scale [ASES]), OA pain, stiffness, physical function (Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC]), and physical and mental health (Short Form 12-Item health survey physical component and mental component summaries). Depression status was assessed by blinded diagnostic interview (the Mini-International Neuropsychiatric Interview) at intake and followup.
Intent-to-treat analyses indicated between-group superiority of iCBT over TAU on the primary outcomes (PHQ-9: Hedges g = 1.01, 95% confidence interval [95% CI] 0.47, 1.54; K-10: Hedges g = 0.75, 95% CI 0.23, 1.28), at postintervention and 3-month followup (PHQ-9: Hedges g = 0.90, 95% CI 0.36, 1.44; K-10: Hedges g = 0.94, 95% CI 0.41, 1.48), and on secondary OA-specific measures (ASES: Hedges g = -0.81, 95% CI -0.29, -1.33; WOMAC: Hedges g = 0.56-0.65, 95% CI 0.04, 1.18) at the 3-month followup. The majority of iCBT participants (84%) no longer met diagnostic criteria at 3-month followup.
Results support the efficacy of an iCBT program (requiring no face-to-face contact) for depression in individuals with comorbid depression and OA of the knee. Importantly, the benefits of the program extended beyond reduced depressive symptoms and distress to include increased self-efficacy and improved pain, stiffness, and physical function at followup.