Primary care quality and addiction severity: A prospective cohort study

Background. Alcohol and drug use disorders are chronic diseases that require ongoing management of physical, psychiatric, and social consequences. While specific addiction-focused interventions in primary care are efficacious, the influence of overall primary care quality (PCQ) on addiction outcomes has not been studied. The aim of this study was to prospectively examine if higher PCQ is associated with lower addiction severity among patients with substance use disorders. Study Population. Subjects with alcohol, cocaine, and/or heroin use disorders who initiated primary care after being discharged from an urban residential detoxification program. Measurements. We used the Primary Care Assessment Survey (PCAS), a well-validated, patient-completed survey that measures defining attributes of primary care named by the Institute of Medicine. Nine summary scales cover two broad areas of PCQ: the patient-physician relationship (communication, interpersonal treatment, thoroughness of the physical exam, whole-person knowledge, preventive counseling, and trust) and structural/organizational features of care (organizational access, financial access, and visit-based continuity). Each of the three addiction outcomes (alcohol addiction severity (ASI-alc), drug addiction severity (ASI-drug), and any drug or heavy alcohol use) were derived from the Addiction Severity Index and assessed 6-18 months after PCAS administration. Separate longitudinal regression models included a single PCAS scale as the main predictor variable as well as variables known to be associated with addiction outcomes. Main Results. Eight of the nine PCAS scales were associated with lower alcohol addiction severity at follow-up (p <=.05). Two measures of relationship quality (communication and whole-person knowledge of the patient) were associated with the largest decreases in ASI-alc (-0.06). More whole-person knowledge, organizational access, and visit-based continuity predicted lower drug addiction severity (ASI-drug: -0.02). Two PCAS scales (trust and whole-person knowledge of the patient) were associated with lower likelihood of subsequent substance use (adjusted odds ratio, [AOR]=0.76, 95 percent confidence interval [95% CI] =0.60, 0.96 and AOR=0.66, 95 percent CI=0.52, 0.85, respectively). Conclusion. Core features of PCQ, particularly those reflecting the quality of the physician-patient relationship, were associated with positive addiction outcomes. Our findings suggest that the provision of patient-centered, comprehensive care from a primary care clinician may be an important treatment component for substance use disorders.