A Before and After Analysis of Health Care Utilization by Patients Enrolled in Opioid Controlled Substance Agreements for Chronic Noncancer Pain

Objective: To evaluate the impact of opioid controlled substance agreements (CSAs) enrollment on health care utilization. Patients and Methods: We retrospectively evaluated health care utilization changes among 772 patients receiving long-term opioid therapy for chronic noncancer pain enrolled in a CSA between July 1, 2015, and December 31, 2015. We ascertained patient characteristics and utilization 12 months before and after CSA enrollment. Decreased utilization was defined as a decrease of 1 or more hospitalizations or emergency department visits and 3 or more outpatient primary and specialty care visits. Multivariate modeling assessed demographic characteristics associated with utilization changes. Results: The 772 patients enrolled in an opioid CSA during the study period had a mean ± SD age of 63.5±14.9 years and were predominantly female, white, and married. The CSA enrollment was associated with decreased outpatient primary care visits (odds ratio [OR], 0.16; 95% CI, 0.14-0.19) and increased diagnostic radiology services (OR, 1.22; 95% CI, 1.02-1.47). After CSA enrollment, patients with greater comorbidity (Charlson Comorbidity Index score >3) were more likely to have reduced hospitalizations (adjusted OR, 2.8; 95% CI, 1.3-6.0; P=.008), reduced outpatient primary care visits (adjusted OR, 2.0; 95% CI, 1.2-3.2; P=.005), and reduced specialty care visits (adjusted OR, 2.0; 95% CI, 1.2-3.3; P=.006). Conclusion: For patients receiving long-term opioid therapy for chronic noncancer pain, CSA enrollment is associated with reductions in primary care visits and increased radiologic service utilization. Patients with greater comorbidity were more likely to have reductions in hospitalizations, outpatient primary care visits, and outpatient specialty clinic visits after CSA enrollment. The observational nature of the study does not allow the conclusion that CSA implementation is the primary reason for these observed changes.