Primary aldosteronism (PA) has a prevalence of about ten percent in a hypertensive population and is an important risk factor for cardiovascular disease. The aldosterone to renin concentration ratio (ARR) is an established diagnostic tool in the screening for PA. However, hormonal determinations are time-consuming and expensive. Therefore, we studied the value of the sodium to urinary sodium to potassium to urinary potassium (SUSPUP) ratio in 37 patients with PA, in 34 hypertensive patients to whom this diagnosis could be excluded (HTN).
The patients groups (PA and HTN) did not differ significantly with respect to sex, age (57.7±1.6 vs 56.3±2.3, respectively), systolic and diastolic blood pressure (means 156 over 93 vs 148 over 88 mmHg). As expected there was a significant difference in the ARR (135.6±98.8 vs 21.7±45.3, respectively) and in plasma aldosterone and renin concentrations. Analysis of the serum and urinary elecrolyte concentrations showed that patients with PA had a significant higher SUSPUP ratios than did patients with HTN (36.9±26.4 vs 16.2±8.5, respectively). Interestingly, treatment with hydrochlorothiazide (HCT) did not interfere significantly with the SUSPUP ratios in PA and HTN.
After spironolactone treatment of patients with PA or operation of aldosterone-producing adenomas the SUSPUP ratios became significantly lower (24.2±11.7) as renin concentrations and blood pressure became normal.
We conclude that the SUSPUP ratio is a cheap tool helpful for the characterization of mineralocorticoid excess syndromes such as PA.