Outcomes and Resource Utilization in ST-Elevation Myocardial Infarction in the United States: Evidence for Socioeconomic Disparities

Background-Socioeconomic status (SES) as reflected by residential zip code status may detrimentally influence a number of prehospital clinical, access-related, and transport variables that influence outcome for patients with ST-elevation myocardial infarction (STEMI) undergoing reperfusion. We sought to analyze the impact of SES on in-hospital mortality, timely reperfusion, and cost of hospitalization following STEMI. Methods and Results-We used the 2003-2011 Nationwide Inpatient Sample database for this analysis. All hospital admissions with a principal diagnosis of STEMI were identified using ICD-9 codes. SES was assessed using median household income of the residential zip code for each patient. There was a significantly higher mortality among the lowest SES quartile as compared to the highest quartile (OR [95% CI]: 1.11 [1.06 to 1.17]). Similarly, there was a highly significant trend indicating a progressively reduced timely reperfusion among patients from lower quartiles (OR [95% CI]: 0.80 [0.74 to 0.88]). In addition, there was a lower utilization of circulatory support devices among patients from lower as compared to higher zip code quartiles (OR [95% CI]: 0.85 [0.75 to 0.97]). Furthermore, the mean adjusted cost of hospitalization among quartiles 2, 3, and 4, as compared to quartile 1 was significantly higher by $913, $2140, and $4070, respectively. Conclusions-Patients residing in zip codes with lower SES had increased in-hospital mortality and decreased timely reperfusion following STEMI as compared to patients residing in higher SES zip codes. The cost of hospitalization of patients from higher SES quartiles was significantly higher than those from lower quartiles.