Is It Possible to Screen for Primary Aldosteronism Effectively in Primary Care?

Objective: Primary aldosteronism (PA) is the commonest secondary cause of hypertension but case-detection remains a challenge. Screening is usually performed in secondary care using an aldosterone:renin ratio (ARR) measurement. Here, we describe the outcomes of screening in primary care, in Oxfordshire, UK.

Design: Retrospective observational study.

Patients: Adults screened for PA in primary care services in Oxford between 2008 and 2022.

Measurements: ARR test results in primary care and outcomes of secondary care evaluation (ARR, saline infusion test, final diagnosis). Primary care and secondary care ARR tests were compared for correlation, concordance and performance in predicting PA.

Results: Among 2915 adults screened in primary care, 455 were referred to secondary care and 107 (3.7% of total population screened) were diagnosed with PA. Primary care ARR showed strong correlation with secondary care ARR (r = 0.841, p < 0.001). Area under the ROC curve to predict PA was 0.81 (95% CI 0.77-0.86) for primary care ARR testing. Primary care ARR cut-off of ≥ 30 pmol/mU showed comparable sensitivity (91.7% vs 92.1%, p = 0.467) to and modest concordance (Kappa 0.583, p < 0.001) with secondary care ARR. Use of beta-blockers were associated with higher risk of false positive test result (OR 3.5, 95% CI 1.1-12.0, p = 0.042).

Conclusions: Screening for PA in primary care with ARR is feasible with modest concordance and comparable sensitivity to secondary care testing. Simple referral criteria and raising awareness among primary care colleagues could ensure appropriate referral to secondary care.