Older adults with knee osteoarthritis (OA) and comorbid subsyndromal depressive symptoms are at elevated risk for incidental major depression or anxiety disorders. Using an indicated prevention paradigm, the authors conducted a sequenced multiple assignment randomized trial (SMART) to: 1) evaluate the effect of cognitive behavioral therapy (CBT) and physical therapy (PT), together with the temporal ordering of these interventions, on patient-reported global impression of change (P-GIC), mood, anxiety, and pain; and 2) compare the strategies' impact on incidence of common psychiatric disorders over 12-months.
This intervention development trial compared four adaptive strategies delivered in two stages (each up to 8 weeks), contrasted with enhanced usual care (EUC). The strategies were CBT followed by an increased dose of CBT (CBT-CBT), CBT followed by PT (CBT-PT), PT followed by an increased dose of PT (PT-PT), and PT followed by CBT (PT-CBT). Participants (n = 99) were aged 60 years and older and met clinical criteria for knee OA and subthreshold depression. Response was defined as at least "much better" on the P-GIC. Participants were assessed quarterly for 12 months for incidence of psychiatric disorders.
Stage 1 response was higher for PT (47.5%) compared to CBT (20.5%). Non-responders receiving an additional dose of the same intervention experienced a response rate of 73%, higher than for switching to a different intervention. All strategies were superior to EUC (5%). Although not powered to detect effects on disorders, neither intervention strategy nor response status affected 12-month incidence of depression and anxiety disorders.
As response rates were similar for PT-PT and CBT-CBT, it may be dose and not type of these interventions that are necessary for clinical benefit. For non-responders, this finding may guide providers to stay the clinical course for up to 12 weeks before switching. These results support future trials of SMART designs in late-life depression prevention.