Medical Diagnoses Associated with Substance Dependence among Inpatients at a Large Urban Hospital

BACKGROUND: There are limited data on reasons for hospital admission among patients dependent on substances other than alcohol. We compared primary discharge diagnoses for heroin- or cocaine-dependent patients to non-dependent patients. MATERIAL AND METHODS: We evaluated a cohort of patients admitted to a general medicine service at a public teaching hospital during July 2005-June 2008. Through bedside interviews, we identified patients who had substance-use disorders. We categorized patients by substance used, route of administration, and dependent or non-dependent use. We grouped diagnostic codes (i.e., ICD-9) using Healthcare Utilization Project categories. We excluded HIV-infected patients. RESULTS: Of 11,397 patients, 341 (3.0%) were dependent on inhalational heroin, 260 (2.3%) on non-injection cocaine, and 106 (0.9%) on injection heroin. Compared to non-dependent patients, inhalational heroin-dependent patients were over three-fold more likely to have been admitted for respiratory diseases (28% vs. 8%, p<0.01); this association was strongest for asthma exacerbation (OR=7.0; 95% CI, 4.7 to 70.4, p<0.01). Of the 225 admissions for an asthma exacerbation, 44 (19.6%) had co-occurrent heroin-dependence. The most frequent diagnostic category among cocaine-dependent patients was circulatory, which was similar to non-dependent patients (22% vs. 21%, p=0.92). DISCUSSION: There is a strong association between heroin dependence and hospital admission for an asthma exacerbation. Provision of specialized substance-use treatment for inhalational heroin users will be necessary to reduce the frequency of exacerbations and repeat hospital admissions.