OBJECTIVES: Atherosclerotic cardiovascular disease (ASCVD) remains the leading cause of mortality and disability in the United States and worldwide. This study aims to assess the multimorbidity burden and its associations with adverse cardiovascular events (ACE) and healthcare costs among patients with ASCVD.

METHODS: This is a retrospective observational cohort study using Aetna administrative claims database. Patients with ASCVD were identified during the study period (1/1/2018-10/31/2021). The earliest ASCVD diagnosis date was identified as index date. Qualified patients were ≥18 years of age and had ≥12 months of health plan enrollment before and after the index date. Comorbid conditions were assessed using all data available within 12 months prior to and including the index date. Association rule mining was applied to identify comorbid condition combinations. ACEs and healthcare costs were assessed using all data within 12 months after the index date. Multivariable generalized linear models were performed to examine the associations between multimorbidity and ACEs and healthcare costs, adjusting for sociodemographic factors.

RESULTS: Of 223,923 patients with ASCVD (mean [SD] age, 73.6 [10.7] years; 42.2% female), 98.5% had ≥2, and 89.1% had ≥5 comorbid conditions. The most common comorbid condition dyad was hypertension - hyperlipidemia (78.7%). The most common triad was hypertension - hyperlipidemia - pain disorders (61.1%). The mean [SD] number of comorbid conditions was 7.1 [3.2]. The multimorbidity burden tended to increase in older age groups and was higher in females than males and higher in patients with lower household income than with higher incomes and higher in higher social vulnerability than in lower vulnerability. The increased number of comorbid conditions was significantly associated with increased ACEs and increased healthcare costs.

CONCLUSIONS: Multimorbidity was extremely prevalent among patients with ASCVD. Multimorbidity patterns varied considerably across ASCVD patients and by age, gender, household income, and social vulnerability status. Multimorbidity was strongly associated with ACEs and healthcare costs.