Context: Primary aldosteronism (PA) is associated with vascular end-organ damage.

Objective: Our objective was to evaluate differences regarding comorbidities between the hypokalemic and normokalemic form of PA.

Design and Setting: This was a retrospective cross-sectional study collected from six German centers (German Conn’s registry) between 1990 and 2007.

Patients: Of 640 registered patients with PA, 553 patients were analyzed.

Main Outcome Measures: Comorbidities depending on hypokalemia or normokalemia were examined.

Results: Of the 553 patients (61 ± 13 yr, range 13–96), 56.1% had hypokalemic PA. The systolic (164 ± 29 vs. 155 ± 27 mm Hg; P < 0.01) and diastolic (96 ± 18 vs. 93 ± 15 mm Hg; P < 0.05) blood pressures were significantly higher in hypokalemic patients than in those with the normokalemic variant. The prevalence of cardiovascular events (angina pectoris, myocardial infarction, chronic cardiac insufficiency, coronary angioplasty) was 16.3%. Atrial fibrillation occurred in 7.1% and other atrial or ventricular arrhythmia in 5.2% of the patients. Angina pectoris and chronic cardiac insufficiency were significantly more prevalent in hypokalemic PA (9.0 vs. 2.1%, P < 0.001; 5.5 vs. 2.1%, P < 0.01). Overall, cerebrovascular comorbidities were not different between hypokalemic and normokalemic patients, however, stroke tended to be more prevalent in normokalemic patients.

Conclusions: Our data indicate a high prevalence of comorbidities in patients with PA. The hypokalemic variant is defined by a higher morbidity than the normokalemic variant regarding some cardiovascular but not cerebrovascular events. Thus, PA should be sought not only in hypokalemic but also in normokalemic hypertensives because high-excess morbidity occurs in both subgroups.