Medical encounters for opioid-related intoxications in Southern Nevada: sociodemographic and clinical correlates

Despite today’s heightened concern over opioid overdose, the lack of population-based data examining clinical and contextual factors associated with opioid use represents a knowledge gap with relevance to prevention and treatment interventions. We sought to quantify rates of emergency department (ED) visits and inpatient hospitalizations for harmful opioid effects and their sociodemographic differentials as well as clinical correlates in Southern Nevada, using ED visit and hospital inpatient discharge records from 2011 to 2013.

Cases were identified by ICD-9-CM diagnosis codes for opioid poisoning and opioid-type drug dependence and abuse as well as poisoning and adverse effect E-codes. Comorbid conditions, including pain-related diagnoses, major chronic diseases, affective disorders, sleep disorders, sexually transmitted infections and viral hepatitis were assessed from all available diagnosis fields. Counts by age-race per zip code were modeled by negative binomial regression. Opioid injuries were further examined as a function both of neighborhood income and individual characteristics, with mixed-effects logistic regression to estimate the likelihood for an adverse outcome.

Opioid intoxications and comorbidities were more common in low-income communities. The multivariable-adjusted rate for opioid-related healthcare utilization was 42 % higher in the poorest vs. richest quartile during the study period. The inter-quartile (quartile 1 vs. 4) rate increases for chronic bodily pains (44 %), hypertension (89 %), renal failure/diabetes (2.6 times), chronic lower respiratory disease (2.2 times), and affective disorders (57 %) were statistically significant. Chronic disease comorbidity was greater among non-Hispanic blacks, whereas abuse/dependence related disorders, alcohol or benzodiazepine co-use, chronic bodily pains, and affective disorders were more prevalent among non-Hispanic whites than nonwhites.

There were consistent patterns of disparities in healthcare utilization across sociodemographic groups for opioid-associated disorders. Further initiatives to evaluate the determinants of overdose and abuse and to implement targeted response efforts are needed.