Endocrine Abstracts

JOINT3614

Background: Primary hyperaldosteronism (PA) is more prevalent than previously recognized. The prevalence of PA in patients with undiagnosed and untreated hypertension (HT) is less known. In a prior population-based study, REFINE-REYKJAVIK study (RRS), carried out in Iceland 2005–2006, 8815 men and women born between 1935 and 1985, and living in the Reykjavik area, were randomly drawn from the Icelandic national registry. Of those, 6941 (73%) individuals attended the study. Thereof, 420 participants were diagnosed with previously unrecognized and untreated HT. The aim of the presented study is to evaluate serum aldosterone (s-aldosterone), plasma renin (p-renin) and their ratio (ARR) taken at baseline and the difference between participants with HT in comparison to normotensive (NT) counterparts.

Methods: As part of RRS, systolic (SBP) and diastolic (DBP) blood pressure was measured at baseline, and HT diagnosed if SBP was over 140 mmHg and/or DBP over 90 mmHg. Blood samples were collected between 08 and 10 AM (68%), 10–12 AM (30%) and few after 12 PM (1.5%). The specimens, initially cooled for up to maximum of 6 hours before being frozen at −80°C and stored. S-aldosterone and p-renin was measured in the 402 HT patients and the 207 NT participants. A Mann–Whitney U test was implemented in comparing the groups. Statistics were performed by using datatab.net.

Results: The mean value for s-aldosterone was 253.09 pmol/l±167.58 in HT (n=402) and 267.5 pmol/l±170.8 in NT (n=207), the difference was not significant (P=0.817). The mean value for p-renin was 11.15 mIU/l±11.32 in HT and 13.56 mIU/l±11.2 in NT. The difference was significant P<0.001. The ARR in the HT group was 39.95±39.11 and 29.64±23.49 in the NT group, the difference was significant, P=0.005. Mean serum potassium levels for the groups was 4.22 mmol/l±0.28 in HT and 4.19 mmol/l±0.27 in NT, the difference was not significant P=0.952.

Discussion: These findings show that p-renin was significantly lower in the HT group compared to the NT group and ARR was thus significantly higher in individuals with newly diagnosed and untreated HT compared to NT counterparts. These findings emphasize the importance of using aldosterone, renin and ARR in patients with newly diagnosed HT. As PA seems to be largely underdiagnosed; these findings support the need to screen for PA at the time of diagnosis of HT.