Rural-urban differences in acute myocardial infarction mortality: Evidence from Nebraska

Acute myocardial infarction (AMI) remains a major cause of death and disability in the United States and worldwide. Despite the importance of surveillance and secondary prevention, the incidence of and mortality from AMI are not continuously monitored, and little is known about survival outcomes after 30 days of AMI hospitalization or associated risk factors, especially in the rural areas. The current study examines rural-urban differences in both in- and out-hospital survival outcomes for AMI patients.

We performed a retrospective analysis using hospital discharge data in Nebraska for January 2005 to December 2009 and Nebraska death certificate records through October 2011. Multivariate logistic regression was used to estimate the rural-urban difference in 30-day mortality. A Cox proportional hazard model was used to predict out-of-hospital and overall survival rate.

In the 30-day mortality model, after controlling for age, comorbidities, and rehabilitation, patients in urban areas were less likely to die than patients in rural areas (odds ratio: 0.709, 95% confidence interval: 0.626-0.802). In the overall survival model, patients in urban areas had a lower hazard of AMI death (hazard ratio: 0.86, 95% confidence interval: 0.806-0.931) than patients in rural areas. Patients with a previous history of heart failure had a significantly higher likelihood of 30-day mortality, while atrial fibrillation, heart failure, and chronic kidney disease were associated with lower overall survival. Patients who attended at least 1 cardiac rehabilitation session had significantly lower 30-day and overall mortality (p < 0.0001).

This study confirms previous findings on rural-urban disparities in 30-day mortality following AMI hospitalization, and reports new findings on overall rural-urban mortality disparity. The study also found an association between cardiac rehabilitation and reduced mortality, a finding never before reported at the population level. Further efforts are needed to develop systems in rural hospitals and communities to ensure that AMI patients receive recommended care.