Patients with PCOS who used contraceptives at higher risk for VTE

Issue: February 2013

Patients with polycystic ovary syndrome who also took oral contraceptives had a twofold increased risk for developing venous thromboembolism, according to data published in the Canadian Medical Association Journal.

“We found a 2-fold increased risk of venous thromboembolism among women with [polycystic ovary syndrome, PCOS] taking combined oral contraceptives compared with matched controls,” the researchers wrote. “We found a similar increased risk when we expanded the definition of [PCOS] by including its symptoms and treatment.”

Further analyses demonstrated a 1.5-fold increased relative risk for VTE in women who were not taking contraceptives with PCOS, they added.

The researchers utilized the IMS LifeLink Health Plan Claims Database to develop a population-based cohort for the study, which took place from May 2001 to December 2009. They included women aged 18 to 46 years taking combined oral contraceptives (i.e. ≤0.035 mg ethinyl estradiol: desogestrel, drospirenone, levonorgestrel, norethindrone, norethindrone acetate, norgestimate or norgestrel) and were diagnosed with PCOS (n=46,867). The matched control group included an additional 43,506 patients.

The incidence of VTE in women with PCOS (HR=2.14; 95% CI, 1.41-3.24) was 23.7 per 10,000 person-years vs. 10.9 per 10,000 person-years for matched controls, study results showed.

Conversely, incidence of VTE in women with PCOS who were not taking oral contraceptives (RR=1.55; 95% CI, 1.10-2.19) was 6.3 per 10,000 person-years compared with 4.1 per 10,000 person-years for those in the matched control group.

The researchers suggest that physicians consider these findings when assessing the risk for VTE before prescribing oral contraceptives to this patient population.

Reference:

Bird ST. CMAJ. 2012;doi:10.1503/cmaj.120677.

Disclosure:

The researchers report consulting relationships with Pfizer and the Observational Medical Outcomes Partnership.