Aldosterone to Renin Ratio (What does it mean?)

[Guest guest]

Airlinerg's Aldosterone / Renin test results:

On 10/29/07 my Aldosterone was 31 and my Renin was 0.2 so the ratio

was 155.

On 7/30/07 my Aldosterone was 20 and my Renin was 0.2 so the ratio was

100.

On 4/30/07 my Aldosterone was 24 and my Renin was 0.2 so the ratio was

120.

On 2/9/07 my Aldosterone was 42 and my Renin was 0.3 so the ratio was

140.

What does this mean?

1st study below says:

In the absence of hypokalaemia, a low plasma renin is a sufficient

and simple way of detecting spironolactone responders among patients

with resistant hypertension.

2nd study below says:

In this study, an ARR >66.9 after 30 minutes seated confirmed primary

hyperaldosteronism, whereas an ARR <23.6 excluded it with near

certainty.

_______________________________________________________________________

In an article at:

http://www-

clinpharm.medschl.cam.ac.uk/pages/publications/documents/Clin_Med_2005_

5_55.pdf

Prevalence of primary hyperaldosteronism assessed

by aldosterone/renin ratio and spironolactone testing

by Sue Hood, Cannon, Foo and Brown

ABSTRACT - Recent studies have suggested that

primary hyperaldosteronism may be present in

more than 10% of patients with hypertension. We

aimed to estimate the prevalence in unselected

patients in primary care, and investigate the

influence of current drug treatment upon the

aldosterone/renin ratio (ARR) and its prediction

of blood pressure response to spironolactone. We

measured blood pressure, plasma electrolytes,

renin activity and aldosterone in 846 patients

with hypertension. Spironolactone 50 mg was

prescribed for one month to patients with blood

pressure >130/85 mmHg and ARR >400. The

primary outcome measure was to discover the

proportion of patients with plasma aldosterone

>400 pmol/l and ARR >800 and either an adrenal

adenoma on computed tomography scan or a

systolic blood pressure response to spironolactone

>20 mmHg. Only one patient had an adenoma,

and only 16 (1.8%) had both a plasma

aldosterone >400 pmol/l and ARR >800. By contrast,

119 patients (14.1%) had an elevated ARR

but normal plasma aldosterone. In 69 patients

out of the 119 who received spironolactone,

blood pressure fell by 26/11 mmHg. These

patients were normokalaemic but had uncontrolled

hypertension despite multiple drugs. The

response to spironolactone was best predicted by

a low plasma renin, <0.5 pmol/ml/h (<10 mU/l),

despite treatment with an ACE inhibitor. We concluded

that adrenal adenomas are an uncommon

cause of hypertension. In the absence of

hypokalaemia, a low plasma renin is a sufficient

and simple way of detecting spironolactone responders

among patients with resistant hypertension.

Only patients with both hypokalaemia

and low plasma renin, measured while the patient

is off | " ) blockade, require measurement of aldosterone.

A plasma aldosterone >400 pmol/l

together with renin activity <;0.5 pmol/ml/h

should trigger further investigations for an

adrenal adenoma.

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Another article at:

http://general-medicine.jwatch.org/cgi/content/full/2005/211/1

Aldosterone-Renin Ratio in Primary Hyperaldosteronism

by Allan S. Brett, MD

Determining the ARR was enough to confirm or exclude diagnoses of

primary aldosteronism in some, but not all, cases; it's probably best

to make sure that patients are evaluated by experienced physicians.

The aldosterone-renin ratio (ARR) has gained popularity as a screening

test for primary hyperaldosteronism, a probably underdiagnosed cause

of hypertension. However, studies have yielded varying definitions of

a positive test.

In this retrospective study from Hong Kong, researchers analyzed

results from 62 patients referred to a hospital's endocrine unit with

suspected primary hyperaldosteronism (usually because of hypertension

plus hypokalemia). Final diagnoses were based on surgical pathology,

saline suppression tests, computed tomography findings, and adrenal

venous sampling (not all patients underwent all tests). ARRs were

determined in each patient after overnight recumbency, after sitting

for 30 minutes, and after 4 hours of ambulation.

Primary hyperaldosteronism ultimately was diagnosed in 45 patients;

the other 17 were presumed to have essential hypertension. After

reviewing all ARR results, the authors conclude that testing patients

after 30 minutes seated is acceptable for screening. An ARR cutoff of

23.6 ng/dL per ng/mL · hour had a sensitivity of 97% and specificity

of 94%. A cutoff of 66.9 yielded 100% specificity: All patients with

levels above this cutoff had primary hyperaldosteronism. The median

ARR was 136.4 among patients with hyperaldosteronism and 5.6 among

controls.

Comment: In this study, an ARR >66.9 after 30 minutes seated confirmed

primary hyperaldosteronism, whereas an ARR <23.6 excluded it with near

certainty. Between these two cutoffs, additional tests were needed to

confirm or exclude the diagnosis. Because of other important variables

(e.g., performance of specific test kits, differing patient

populations across studies), it's probably best to have patients

evaluated by physicians with experience in diagnosing primary

hyperaldosteronism.

— Allan S. Brett, MD