Advanced Trainee General Medicine, Christchurch Hospital
Retrospective analysis of treated
primary aldosteronism in a single centre hypertensive cohort
J Llewelyn1, V
Mathavan2, I Phillips3, A Spencer4,T Cawood5
1Advanced trainee General Medicine, Christchurch Hospital.
2Advanced trainee General Medicine, Christchurch Hospital.
3Consultant Pathologist, Christchurch Hospital.
4Consultant Physician, Christchurch Hospital
5Consultant Endocrinologist and General Physician, Christchurch
Background/Aims: There is wide variation in
the estimated prevalence of primary aldosteronism (PA) amongst hypertensive
patients in the literature, ranging from 3% up to 20% (Galati et al 2013, Chao
et al 2016). Our aim was to determine the prevalence of treated PA in a local
hypertensive population using an aldosterone-renin ratio (ARR) as the initial
Methods: All ARRs performed at
Canterbury Health Laboratory from 1/6/14 to 31/12/15 were obtained. Patients
under 18 and/or those with pre-existing adrenal pathology were excluded.
Prevalence of treated PA in those with an abnormal ARR on any combination of
antihypertensive medications was estimated. The cut-off value for an abnormal
ARR was greater than 30.5 ng/dl per ng/ml/h when the serum aldosterone is above
Results: During the 18 months, 177
hypertensive patients had an ARR. The male:female ratio was 0.82 and the mean
age 53.2 ± 16.8 years. An abnormal ARR was found in 36/177 (20.3%). Saline
suppression testing was performed on 15/36 patients, with 2 positive results.
Of the 21 remaining, 3 were treated as PA on clinical grounds. The prevalence
of treated PA in this cohort is 5/177 (2.8%).
Conclusion: The prevalence of treated
PA in our local hypertensive cohort is lower than that reported in the
Possible reasons include a higher threshold
to screen patients, higher cut-off value for an abnormal ARR, false negatives
with certain antihypertensive medications, and a proportion of those with
abnormal ARRs had no confirmatory testing.
It would be interesting to establish
the true prevalence of PA in this cohort without confounding medications.
Galati, S et al., September 2013.
Primary aldosteronism: emerging trends. Trends in Endocrinology and
Metabolism, Vol 24;No.9
Chao C et al. March 2016. Diagnosis and management of primary aldosteronism: An
updated review. Annals of Medicine. Vol 45;No. 4