Active renin mass concentration to determine aldosterone-to-renin ratio in screening for primary aldosteronism

Figures & data

Figure 1 Individual values of plasma aldosterone, active renin mass concentration (ARC) and aldosterone to renin ratio (ARR) in the three groups.

Figure 2 Analysis of receiver-operating characteristic curves. Circle, plasma aldosterone; triangle, active renin mass concentration; square, aldosterone to renin ratio.

Table 1 Clinical and biochemical data

	Control subjects	Essential hypertension	Primary aldosteronism
Number of subjects	78	95	38
Gender (F/M)	35/43	56/39	13/25
Age (years, mean ± SD)	36 ± 13	51 ± 12	53 ± 11
Serum K (mmol/L)	4.2 ± 0.03 (4.2)	4.1 ± 0.06 (4.2)	3.2 ± 0.07^a (3.2)
Plasma aldosterone (pmol/L)	382 ± 28 (320)	339 ± 25 (272)	928 ± 116^a (664)
ARC (ng/L)	11.3 ± 0.8 (10)	19.7 ± 2.9 (9)	2.3 ± 0.2^a (2)
Aldosterone/ARC ratio (pmol/ng)	42.4 ± 3.3 (32)	37.8 ± 2.9 (27)	519 ± 99^a (278)

Notes:

a P < 0.01 versus control subjects and essential hypertension. Mean ± standard error of the mean. The median value for serum K, plasma aldosterone, ARC, and aldosterone/ARC ratio appears in brackets.

Abbreviation: ARC, active renin mass concentration.

Table 2 Comparison of cutoff values derived from the upper limits of laboratory references or 95th percentile values and those from the receiver-operator characteristic curve

		Cutoff values	Sens/spec. (%)	Sens + spec-1 (%)	Accuracy (%)^a	Kappa test
Aldo	ULR	871 pmol/L	34/95	29	84	0.36
	ROC	480 pmol/L	79/77	56	78	0.43
ARC	ULR	7 ng/dL	100/67	67	78	0.43
	ROC	4.3 ng/dL	100/85	85	88	0.67
ARR	95th percentile	101 pmol/ng	100/95	95	96	0.92
	ROC	130 pmol/ng	100/100	100	100	1.0

Note:

a P < 0.001 for all values. Control and essential hypertension populations were pooled to calculate specificity; the median for ARR is 30.6 with a 95th percentile of 101 (3.3-fold the median).

Abbreviations: Aldo, plasma aldosterone concentration; ARC, active renin mass concentration; ARR, aldosterone-renin ratio; ROC, receiver-operator characteristic curve; ULR, upper limit of laboratory reference values; Sens/spec, sensitivity/specificity.

Table 3 Area under the receiver-operator characteristic curve ± standard error of the mean and confidence intervals

	Area under curve	± SEM	Confidence interval (95%)
Aldo (pmol/L)	0.86^Table Footnotea,Table Footnoteb	0.032	0.79–0.91
ARC (ng/L)	0.96^c	0.012	0.93–0.98
Aldo/ARC ratio (pmol/ng)	1.0	0.002	0.95–1.00

Notes:

a P < 0.01 versus ARC;

b P < 0.001 versus aldo/ARC ratio;

c P < 0.01 versus aldo/ARC ratio.

Abbreviations: Aldo, plasma aldosterone concentration; ARC, active renin mass concentration; SEM, standard error of the mean.

Table 4 Suggested screening thresholds for aldosterone-to-renin ratio using active renin mass concentration (pmol/ng)

≤100	Essential hypertension
100–130	Gray zone (repeat)
≥130	Primary aldosteronism^a

Note:

a Combined with plasma aldosterone concentration > 416 pmol/L.