Can primary aldosteronism and acromegaly be etiological factors in non-obese patients with obstructive sleep apnea syndrome?

Obstructive sleep apnea syndrome (OSAS) is strongly associated with obesity; however, a substantial proportion of patients are non-obese, raising the possibility of underlying endocrine etiologies. This study aimed to investigate the prevalence of primary aldosteronism (PA) and acromegaly in non-obese patients with OSAS and to evaluate the necessity of routine screening. Non-obese individuals, defined as those with a body mass index (BMI) < 30 kg/m², who were diagnosed with OSAS by polysomnography were prospectively evaluated. Clinical characteristics, comorbidities, plasma aldosterone-to-renin activity ratio (ARR), and insulin-like growth factor-1 (IGF-1) levels were assessed. Patients with elevated ARR underwent confirmatory saline infusion testing and adrenal imaging when indicated. Among 103 patients, biochemical evidence of PA according to the original study protocol was identified in 20 patients (19.4%), whereas post hoc application of the 2025 Endocrine Society screening criteria identified 29 patients (28.2%) with a screen-positive/probable PA phenotype. Hypertension was more frequent in patients with primary aldosteronism than in those without primary aldosteronism (70.0% vs. 24.1%). Adrenal adenomas were detected in 3.9% of the cohort. IGF-1 levels were within age- and sex-adjusted reference ranges in all patients, and no cases of acromegaly were identified. These findings suggest that screening for primary aldosteronism may be clinically warranted in non-obese patients with OSAS, whereas routine screening for acromegaly should be reserved for those with suggestive clinical features.