Context: Polycystic ovary syndrome (PCOS) is associated with insulin resistance, hyperandrogenism, and dyslipidemia, but the effects of these disturbances on long-term health are not fully understood.

Aim: Our aim was to determine the relative risk of type 2 diabetes, cancer, large-vessel disease (LVD), and all-cause mortality for women diagnosed with PCOS.

Design: Data were extracted from the General Practice Research Database, a longitudinal, anonymized research database derived from nearly 600 primary-care practices in the United Kingdom. Patients with a diagnosis of PCOS between 1990 and 2010 were selected. Patients were matched to two sets of controls. The first set was matched according to primary-care practice and age, and the second was also matched on body mass index. Primary outcome was first incident record of diabetes. Crude rates for diabetes were presented, and time to diabetes was analyzed using Cox proportional hazard models. Secondary outcomes (cancer, LVD, and mortality) were also modeled.

Results: Of 53,303 identified with a diagnosis of PCOS, 21,740 (40.8%) met the eligibility criteria. Median follow-up was 4.7 yr (interquartile range = 2.0-8.6 yr) in those with PCOS and 5.8 yr (2.7-9.6) in the reference group. Crude rates of diabetes were 5.7 and 1.7 per 1000 patient-years for cases and controls, respectively. The corresponding adjusted hazard ratio was 3.015 (95% confidence interval = 2.733-3.327). Of cases matched by body mass index, crude rates of diabetes were 4.7 and 2.4 per 1000 patient-years, respectively. The corresponding adjusted hazard ratio was 1.752 (1.514-2.028). No significant difference in BMI-adjusted risk was evident for cancer, LVD, or all-cause mortality.

Conclusions: During this follow-up period, women with PCOS were not at increased risk of LVD, cancer, or death, but they had increased risk of type 2 diabetes.