A latent class analysis of clinical complexity: Secondary analysis of the collaboration leading to addiction treatment and recovery from other stresses (CLARO) randomized trial

BACKGROUND AND AIMS: Individuals with opioid use disorder (OUD) frequently present with co-occurring mental health conditions such as depression and posttraumatic stress disorder (PTSD), along with other mental health substance use disorders, physical health conditions and social determinants that together comprise 'clinical complexity.' Collaborative care (CC), a primary care-based behavioral health integration model, aims to improve outcomes through coordinated, patient-centered treatment. This study examined heterogeneity in baseline clinical complexity among participants in the CLARO (Collaboration Leading to Addiction Treatment and Recovery from Other Stresses) trial and assessed whether the effects of CC versus enhanced usual care (EUC) differed across clinical complexity groups. METHODS: Secondary analysis of CLARO, a pragmatic randomized clinical trial (n = 797) of CC versus EUC for adults with OUD and depression and/or PTSD, conducted in 18 low-resourced primary care clinics in New Mexico and California, USA. Latent class analysis of baseline data identified subgroups defined by mental health and substance use as the main characteristics along with physical health and social challenges. Six-month treatment effects were estimated using one-step models that jointly estimated latent class membership and class-specific outcomes, incorporating class × treatment interactions. Outcomes included depression symptom severity, PTSD symptom severity, and buprenorphine utilization and prescribing duration. RESULTS: Three subgroups were identified: (1) low complexity (43%), with relative clinical and social stability; (2) mental health complexity (34%), with high psychiatric symptoms but lower substance use and moderate social adversity; and (3) high dual complexity (23%). Compared with EUC, CC was associated with lower depression severity at follow-up for the low-complexity class, but not for other classes. CC and EUC did not differ statistically significantly with respect to PTSD outcomes in any class. Buprenorphine utilization and prescribing duration outcomes were similar across CC and EUC treatment arms. CONCLUSIONS: The effects of collaborative care may vary according to patients' baseline clinical complexity. Collaborative care appears to be associated with more favorable depression outcomes than enhanced usual care among participants with lower clinical complexity but not among those with higher clinical complexity.