National Trends in Heart Failure Hospitalization After Acute Myocardial Infarction for Medicare Beneficiaries Heart

AMI declined modestly from 16.1 per 100 person-years in 1998 to 14.2 per 100 person years in 2010 ( P <0.001). After adjusting for demographic factors, a relative 14.6% decline for HF hospitalizations after AMI was observed over the study period (incidence risk ratio, 0.854; 95% confidence interval, 0.809–0.901). Unadjusted 1-year mortality following HF hospitalization after AMI was 44.4% in 1998, which decreased to 43.2% in 2004 to 2005, but then increased to 45.5% by 2010. After adjusting for demographic factors and clinical comorbidities, this represented a 2.4% relative annual decline (hazard ratio, 0.976; 95% confidence interval, 0.974–0.978) from 1998 to 2007, but a 5.1% relative annual increase from 2007 to 2010 (hazard ratio, 1.051; 95% confidence interval, 1.039–1.064). variable for calendar year were constructed to evaluate how the incident risk ratio for HF hospitalization after AMI changed for a given calendar year compared with the baseline year of 1998; in these models age and sex were aggregated to the year-level. For the mortality analysis, we considered the admission date of the HF hospitalization after AMI as the initial time zero to calculate the proportion of patients who died within 1 year. Mortality was reported in terms of proportion of patients who died within 30, 90, or 180 days or 1 year. Trends in unadjusted HF mortality after AMI were assessed using regression models with a continuous variable of cohort year. We then constructed Cox proportional hazards models to examine changes in mortality after HF following AMI, adjusting for demographics and comorbid conditions. These models included dummy indicator vari-ables that represented how the hazard ratio (HR) for mortality changed for a given calendar year compared with the baseline year of 1998. Analyses were conducted using SAS version 9.3 (SAS Institute Inc., Cary, NC). Significance level was considered to be P <0.01 using 2-sided tests. Institutional Review Board review and approval was obtained through the Yale University Human Investigation Committee. Medicare claims data were provided through a data use agreement with CMS.