Comparing ARR Versus Suppressed PRA as Screening Tests for Primary Aldosteronism.

BACKGROUND

In many practices, the screening for primary aldosteronism relies on a single-blood draw for plasma aldosterone concentration (PAC) and plasma renin activity (PRA) to establish an aldosterone-to-renin ratio (ARR). ARR levels vary between expert centers and repeated assays in the same individual, emphasizing the potential variability of this screening approach. A suppressed PRA to <1 ng/mL per h has been proposed as an alternative test to the ARR.

METHODS

We compared 2 potential screening approaches to identify probable primary aldosteronism (ARR≥30 or ARR≥20 versus PRA suppressed below 1 ng/mL per h) in a cohort of 94 829 paired PRA and PAC samples submitted by clinicians to evaluate the presence of primary aldosteronism.

RESULTS

Of 94 829 patients, 20.3% tested positive based on ARR≥20 (95% CI, 20.0%-20.5%), 13.9% based on ARR≥30 (95% CI, 13.6%-14.1%), versus 45.9% based on suppressed PRA (<1 ng/mL per minute [95% CI, 45.5%-46.2%]). In the PRA group, a range of aldosterone levels was observed: 5.5% had PAC >15 ng/dL, 25.2% had PAC 5 to 15 ng/dL, and 15.2% had PAC <5 ng/dL, compared with 6%, 12.7%, and 1.6% in the ARR≥20 group and 4.7%, 8.5%, and 0.7% in the ARR≥30 group.

CONCLUSIONS

In this cohort of individuals being screened for primary aldosteronism, substantially more individuals were identified using criteria focused on suppression of renin activity compared with using the aldosterone renin ratio as a screening tool.