Progestin-dependent effect of oral contraceptives on plasma aldosterone/renin ratio.

OBJECTIVES

Estrogens in oral contraceptives (OC) may influence plasma aldosterone/plasma renin activity (ALD/PRA) and plasma aldosterone/plasma renin concentration (ALD/DRC) ratios, but the effect of progestins on these ratios has not been sufficiently studied so far.

DESIGN AND

METHODS

PRA (RIA, DiaSorin), DRC and ALD (IRMA, RIA, Beckman Coulter) were measured, then ALD/PRA and ALD/DRC were calculated in 86 healthy normotensive women (aged 27.3 ± 7.5 years), 63 using progestin-containing OC: either gestodene (GTD, n=25), desogestrel (DSG, n=22) or drospirenone (DRSP, n=16). 23 OC-nonusers served as control.

RESULTS

Data are presented as median and lower and upper quartiles. PRA, DRC and ALD levels were higher (p<0.001) in the DRSP group [3.1 (1.5 3.8)ng/mL/h, 25.2 (9.8 30.4)ng/L and 43.7 (28.0 61.6)ng/dL, respectively], than in the DSG [1.4 (1.1 2.1)ng/mL/h, 8.3 (6.8 12.3)ng/L and 11.5 (7.2 16.6)ng/dL], GTD [1.2 (0.8 2.2)ng/mL/h, 8.0 (4.8 10.5)ng/L, and 13.4 (7.7 22.1) ng/dL] and control [1.3 (0.7 1.6) ng/mL/h, 12.2 (7.5 21.7) ng/L, and 10.0 (4.4 14.7) ng/dL] groups. Cases of falsely elevated ALD/PRA and ALD/DRC ratios [7 (11%) and 12 cases (19%) respectively] were only found in OC users but not in the control group. In the DSG and GTD groups, but not in the DRSP group falsely elevated ALD/PRA occurred less frequently than falsely elevated ALD/DRC.

CONCLUSIONS

In OC-users falsely elevated ALD/PRA and especially ALD/DRC are a common finding, particularly when the OC contains DSG or GTD. Therefore, for OC-users method- and progestin-type specific cut-off levels should be established.