BACKGROUND: In adult women, medium dose combined oral contraceptives (COC) cause mild increases in blood pressure (BP). Risks among adolescents initiating COCs have not been well described.
OBJECTIVE: To describe changes in systolic blood pressure (SBP) and diastolic blood pressure (DBP) and body mass index (BMI) associated with initiation and continued use of medium-dose COCs.
DESIGN/METHODS: This observational, matched cohort study was conducted in two large integrated healthcare systems. Utilizing medical and pharmacy claims and electronic medical record data we identified a cohort of adolescents 14-17.9 years of age initiating medium-dose COCs (30 or 35 micrograms of ethinyl estradiol or equivalent) between 7/1/07-12/31/09 with a baseline and at least one follow-up BP and BMI recorded while still utilizing COCs. The 605 COC-users were then matched 1:2 by age, race/ethnicity and site to 1180 COC-non users for the period of observation. COC-non users were assigned an index date equivalent to the COC dispense date. All BPs and BMIs recorded during office visits starting 3 months prior to COC initiation/index date through 12/31/2010 were collected. Using available data, changes in SBP, DBP at 3, 6 and 12 months and change in BMI at 12 months were compared between COC-users and COC-non-users with T-tests. The number of subjects with BP and BMI data at 3, 6, and 12 months following initiation of COC/index date varied.
RESULTS: The full cohort had a mean age of 16.4 years, was 71% white; 96% were privately insured. Among COC-users, mean baseline SBP, DBP and BMI were 107mmHG, 65mmHG and 22.6 kg/m2, respectively; <2% had a baseline SBP or DBP =95th percentile. COC-non-users did not differ significantly by baseline SBP, DBP or BMI. Change in SBP, DBP, and BMI is shown below.
CONCLUSIONS: Compared to non-users, initiation and continued use of medium-dose COCs was not associated with significant increases in SBP, DBP or BMI.