OBJECTIVE: Polycystic ovary syndrome (PCOS) is a complex disorder characterized by a wide range of symptoms related to ovulatory dysfunction and androgen overproduction. Although PCOS is associated with multiple cardiovascular disease (CVD)-risk factors, previous studies have reported controversial associations between PCOS and different types of CVD events. We sought to determine the association of PCOS with various CVD outcomes among hospitalized women. METHODS: All women hospitalizations between the ages of 15 and 65 years recorded in the National Inpatient Sample database, 2017 were analyzed with sampling-weighted logistic regression analysis. The International Classification of Diseases, 10th revision, codes were used to define outcomes including composite CVD, major adverse cardiovascular events (MACEs), coronary heart disease (CHD), stroke/cerebrovascular accident (CVA), heart failure (HF), arterial fibrillation (AF) or arrhythmia, pulmonary heart disease (PHD), myocardial infarction, cardiac arrest, and diabetes. RESULTS: Among the total hospitalizations of women, 13 896 (0.64) had a PCOS diagnosis. Polycystic ovary syndrome was found to be associated with most CVD outcomes, including composite CVD (adjusted odds ratio [aOR] = 1.73, 95% CI, 1.55-1.93, P < .001), MACE (aOR = 1.31, 95% CI, 1.12-1.53, P < .001), CHD (aOR = 1.65, 95% CI, 1.35-2.01, P < .001), stroke/CVA (aOR = 1.46, 95% CI, 1.08-1.98, P = .014), HF (aOR = 1.30, 95% CI, 1.07-1.57, P = .007), AF/arrhythmia (aOR = 2.20, 95% CI, 1.88-2.57, P < .001), and PHD (aOR = 1.58, 95% CI, 1.23-2.03, P < .001) among hospitalized women with an age of ≤40 years. However, the associations between PCOS and CVD outcomes were mediated by obesity and metabolic syndrome conditions. CONCLUSIONS: Polycystic ovary syndrome is associated with CVD events and the association is mediated by obesity and metabolic syndrome conditions, particularly among hospitalized women aged ≤40 years in the United States.