Estimated versus observed 10-year atherosclerotic cardiovascular event rates in a rural population-based health initiative: The Heart of New Ulm Project.

Objective: Assess discrepancy between estimated 10-year atherosclerotic cardiovascular disease (ASCVD) risk and observed 10-year event rates in a rural population participating in cardiovascular health initiative.

Methods: The study included a rural sample of individuals participating in the Heart of New Ulm (HONU), a population-based health initiative aimed at reducing ASCVD risk in a rural community. HONU conducted over 100 baseline screening events with 5221 individuals participating in 2009. For this analysis, we included participants who were aged 40-79 years, free of ASCVD at baseline, and had adequate data to calculate 10-year ASCVD risk. Electronic health record data and state death records were used to determine rates of non-fatal myocardial infarction and stroke, and ASCVD death from 2010-2019. ASCVD event rates were compared to estimated 10-year risks calculated using the Pooled Cohort Equations, stratified by sex and clinically relevant risk categories.

Results: The sample ( = 2819, mean ± SD age 56.1 ± 9.9 years, 59.6% female) had a low prevalence of tobacco use (8.1% current smokers) and diabetes (6.5%) and a high prevalence of hypertension (44.4%) and hyperlipidemia (56.6%). The median estimated 10-year ASCVD risk for the entire sample was 5.7% (IQR 2.3-13.5%) with an observed 10-year ASCVD event rate of 3.4%. The largest gap between observed and estimated risk was in those at intermediate/high (≥7.5%) ASCVD risk (median 10-year risk 15.8% [IQR 10.4-29.0], observed ASCVD event rate 6.4%)

Conclusio: In a sample of rural participants exposed to a multifaceted ASCVD prevention initiative, observed rates of ASCVD were substantially lower compared to estimated ASCVD risk. The potential for significantly lower than predicted ASCVD event rates in certain populations should be included in the clinician-patient risk discussion.