Prevalence, patterns, and correlates of multiple substance use disorders among adult primary care patients.

Addressing multiple substance use disorders (SUDs) in primary care-based screening and intervention may improve SUD treatment access, engagement, and outcomes. To inform such efforts, research is needed on the prevalence and patterns of multiple SUDs among primary care patients. Data were analyzed from a sample of 2,000 adult (aged 18 or older) primary care patients recruited from a multisite NIDA Clinical Trials Network (CTN) study (CTN-0059). Past-year DSM-5 SUDs (tobacco, alcohol, and drug) were assessed by the modified Composite International Diagnostic Interview. Prevalence and correlates of multiple versus single SUDs were examined. Latent class analysis (LCA) was used to explore patterns of multiple SUDs.

Analysis revealed multiple SUDs among the majority of patients with SUD for alcohol, cannabis, prescription opioids, cocaine, and heroin. Participants who were male, ages 26-34, less educated, and unemployed had increased odds of multiple SUDs compared to one SUD. Having multiple SUDs was associated with greater severity of tobacco or alcohol use disorder. LCA of the sample identified three classes: class 1 (83.7%) exhibited low prevalence of all SUDs; class 2 (12%) had high-moderate prevalence of SUDs for tobacco, alcohol, and cannabis; class 3 (4.3%) showed high prevalence of SUD for tobacco, opioids, and cocaine. LCA-defined classes were distinguished by sex, age, race, education, and employment status.

Conclusions: Findings suggest that multiple SUDs are the norm rather than the exception among primary care patients with SUD. Primary care physicians should be aware of multiple SUDs when planning treatment, especially among adults who are male, younger, less educated, or unemployed. However, it should be noted that the treatment and management of multiple SUDs and other associated comorbidities may be out of the scope of expertise for many primary care physicians. This argues for the need of additional approaches to address SUD in primary care, such as the development of coordinated care models and linkage services to improve access to specialty care and follow-up of clinical outcomes.

Related protocols: CTN-0059