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

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.

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.

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.

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.