Hospital Cost and In-hospital Mortality in Substance Abusers Following ST Elevation Myocardial Infarction

Background
Substance abuse (SA) is well known to cause acute and chronic cardiovascular events and poses a significant economic burden. However, effects of SA on outcomes of ST elevation myocardial infarction (STEMI) remain unclear. This study aims to evaluate the outcomes of STEMI in patients with substance abuse disorder.

Methods
A retrospective analysis of National Inpatient Sample was performed to identify all the patients with STEMI (2005-2014). A one to one propensity score matching for the age, gender and hospital region was done. Univariate (Chi Square, ttest) and multivariate logistic regression models were employed. Generalized linear model was used to estimate length of stay and hospitalization cost.

Results
Out of 1,938,097 STEMI patients, 56,860 were SA patients. SA group had higher heart failure (HF) 25% vs. 21%, smoking 64% vs. 43%, and had lower DM 15% vs. 21% as compared to NSA group (All P-value <0.05). (Table 1) In-hospital mortality following STEMI was higher in patients with SA (6.3% vs. 5.6%, P <0.001). After adjusting for potential confounders, SA was associated with higher odds of mortality (OR 1.27, 95% CI: 1.20-1.35, P<.0001). Predictors of total hospitalization cost for STEMI were COPD, HF, A-Fib and stroke (all P-value<0.001), however, cost was not different between two groups (P=0.07).

Conclusions
This study shows that SA is associated with higher in-hospital mortality after STEMI. Cost of hospitalization and is similar in two groups. Further studies are required understand disparity in outcomes of STEMI in SA patients.