Unilateral primary aldosteronism as an independent risk factor for vertebral fracture

Context: Primary aldosteronism (PA) is known to increase vertebral fracture (VF), although the detailed mechanism remains to be elucidated. We hypothesized that the PA subtype is associated with VF. Objective: To evaluate whether unilateral PA is associated with the prevalence of VF. Design: This was a retrospective cross-sectional study in a single referral centre. Patients: We identified 210 hypertensive patients whose clinical data were available for case-detection results. One hundred and fifty-two patients were diagnosed with PA using captopril challenge tests. Measurements: We measured the prevalence of VF, according to PA subtype. Results: One hundred thirteen patients with PA were subtype classified by adrenal vein sampling. Of these, 37 patients had unilateral PA, 76 patients had bilateral PA, 58 patients had non-PA; 39 patients with PA were not subtype-classified. Patients with PA had a higher prevalence of VF (29%, 44/152) than those with non-PA (12%, 7/58; P =.011). Moreover, unilateral PA had a higher prevalence of VF (46%, 17/37) than bilateral PA (20%, 15/76; P =.021). There was no significant difference in the prevalence of VF between bilateral PA and non-PA. Unilateral PA was an independent risk factor for VF after adjusting for age and sex (OR: 3.16, 95% confidence interval: 1.12-8.92; P =.017). Among patients with unilateral PA, serum cortisol concentrations after 1-mg dexamethasone suppression test were higher in those with VF (1.32 ± 0.67 g/dL) than those without (0.96 ± 0.33 g/dL; P =.048). Conclusions: Unilateral PA is an independent risk factor for VF.