A cross-sectional and 10-year prospective study of postmenopausal estrogen therapy and blood pressure, renal function, and albuminuria: the Rancho Bernardo Study.

OBJECTIVE: Blood pressure, urine albumin-to-creatinine ratio, and estimated glomerular filtration rate (GFR) are highly correlated conditions. The longitudinal effect of exposure to postmenopausal estrogen therapy on these traits studied together has not been reported.
METHODS: This was a cross-sectional study of 1,044 older postmenopausal community-dwelling women from the Rancho Bernardo Study (1992-1996); 443 women were reevaluated ∼ 10 years later (2002-2005). We determined the cross-sectional and prospective association of baseline postmenopausal estrogen therapy and blood pressure, urine albumin-to-creatinine ratio, GFR, and the odds of categorical hypertension (physician diagnosis, medication, or blood pressure ≥ 140/≥ 90 mm Hg), chronic kidney disease (GFR ≤ 60 mL/min per 1.73 m2), and albuminuria (urine albumin-to-creatinine ratio ≥ 25 mg/g).
RESULTS: At baseline, the mean age was 68.3 years for current estrogen users, 75.4 years for past users, and 74.3 years for never users. In the cross-sectional analyses, current users had lower diastolic blood pressure and lower odds of having chronic kidney disease, independent of covariates. In the ∼ 10-year follow-up, comparisons between never, past, and current estrogen use (91% continuous use since baseline), the mean diastolic blood pressure declined over time in current users, whereas systolic blood pressure increased among never users. Urine albumin-to-creatinine ratio also increased in never users and decreased in current users; GFR did not differ by estrogen use.
CONCLUSIONS: In cross-sectional analyses, estrogen users had better GFR and blood pressure than nonusers did, but the 10-year follow-up showed improved blood pressure and decreased urine albumin-to-creatinine ratio among mostly long-term current users, without differences in GFR by estrogen use. This study suggests no association of GFR with 10 years of continuous estrogen use and an inverse association with albuminuria.