Improving Patient Reported Outcomes and Preventing Depression and Anxiety in Older Adults With Knee Osteoarthritis: Results of a Sequenced Multiple Assignment Randomized Trial (SMART) Study

Abstract

Objective: 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.

Methods: 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.

Results: 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.

Conclusion: 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.

Trial registration: ClinicalTrials.gov NCT01530204.

Keywords: Knee arthritis; anxiety; cognitive behavioral therapy; depression; physical therapy; prevention.

Figure 1.

Consort Diagram *: 5 out of 12 who were randomized to receive PT (after receiving CBT in the first stage) at the second stage declined intervention. 1 out of 8 who are randomized to receive PT (after receiving PT in the first stage) declined intervention. **: All 8 CBT responders at S8-IE (independent evaluation at week 8) have data at T2; all 19 PT responders at S8-IE have data at T2 ***: One of the 17 non-responders didn’t complete 1^st intervention and didn’t want any further therapy.

Figure 2:. Forest plot for proportion of early response at stage 1 by interventions (a), and proportion for response at stage 2 by strategies (b).

Sample size of CBT-CBT group = 13+8=21, in which 8 people are responders in stage 1 and 13 people are non-responders who get CBT for their 2^nd intervention. Sample size of CBT-PT group = 12+8=20, in which 8 people are responders in stage 1 and 12 people are non-responders who get PT for their 2^nd intervention. Sample size of PT-CBT and PT-PT groups are both = 19+8, in which 19 people are responders in stage 1 and 8 people are assigned to either PT or CBT for their 2^nd intervention.

Figure 3:. Cumulative proportion with any diagnosis comparing responders to non-responders

Despite observed longer time without any diagnosis for responders compared to non-responders, the difference in the cumulative proportion with any diagnosis was not statistically significant (Logrank test z = −1.43, p = 0.153; HR for responders = 0.42; 95% CI 0.13−1.37)