Introduction
Patients with primary aldosteronism (PA) have increased cardiovascular risk, and some studies find medical therapy less effective than surgery. This may be due to side effects and limited efficacy of medications at tolerable doses.
Methods
We conducted a retrospective study on 201 patients with PA treated with medical therapy (spironolactone, eplerenone or amiloride) for PA from 2000-2020 at two tertiary centres. Patients were assessed for efficacy to achieve clinical and biochemical control, and for side effects.
Results
Amongst 155 patients on long-term medications, 57.4% achieved blood pressure <140/90mmHg, 90.1% achieved normokalemia(48.0% achieved potassium≥4.3mmol/L), and 63.2% achieved renin>1ng/ml/hr. Concordance of biochemical control using potassium and renin levels was 49.1%. 52.3% of patients experienced side effects, with 10.3% switching to another medication, 22.6% decreasing dose, and 11.0% stopping medications. Risk factors for side effects were spironolactone use, dose≥50mg, treatment duration ≥1year, male gender and unilateral PA. Patients with unilateral PA, compared to bilateral PA, used higher spironolactone doses, 57mg vs 50mg, P<0.001, and had more side effects, 63.2% versus 41.8%, P=0.008. Amongst 46 patients with unilateral PA who underwent surgery after initial medical therapy, surgery further improved systolic and diastolic BP, from 141 to 135mmHg, P=0.045, and from 85 to 79mmHg, P=0.002, respectively.
Conclusion
Dose-dependent side effects limit the efficacy of medical therapy in PA. Future prospective studies should assess the best monitoring strategy for biochemical control during long-term medical therapy. For unilateral PA, surgery remains preferable to medications, as surgery leads to better control with less long-term side-effects.