Relationship Between the Aldosterone-to-Renin Ratio and Blood Pressure in Young Adults: A Longitudinal Study

Endocrine Hypertension: The Urgent Need for Greater Global Awareness

Hypertension affects about 1.28 billion adults globally, and significantly increases the risk of chronic morbidity and mortality among sufferers. About 15% of these individuals have secondary hypertension, the majority of whom have dysfunction of one or more endocrine systems as the cause of hypertension. Although adrenal disorders are often identified as the cause of endocrine hypertension, extra-adrenal disease and pituitary disorders also can cause the disease. Timely diagnosis is of paramount importance, because of the potential for a surgical cure or optimal disease control with pharmacotherapy to prevent hypertensive complications. Even with its relatively high prevalence compared with many other chronic illnesses, the diagnosis of endocrine hypertension is often delayed or never made because of poor awareness about the disease among physicians. This review attempts to provide an overview of the disease, with some practical aspects of diagnosis and management of a few of the important disorders causing endocrine hypertension.

Aldosterone and renin concentrations and blood pressure in young Indigenous and non-Indigenous adults in the Northern Territory: a cross-sectional study

OBJECTIVES

To evaluate aldosterone and renin levels and aldosterone-to-renin ratios (ARRs) in young Indigenous and non-Indigenous adults in the Northern Territory, and their association with blood pressure levels.

DESIGN

Cross-sectional study; single time point sub-study of two prospective birth cohort studies.

SETTING, PARTICIPANTS

Participants in the Aboriginal Birth Cohort (ABC) - born to Indigenous mothers at the Royal Darwin Hospital during 1987-1990 - and the Top End Cohort (TEC) - people born to non-Indigenous mothers in Darwin, recruited during 2007-2009 - aged 32-35 years at the time of this sub-study.

MAIN OUTCOME MEASURES

Plasma aldosterone and direct renin concentrations; ARRs (positive screening test result for primary aldosteronism defined as > 70 pmol/mU); systolic and diastolic blood pressure.

RESULTS

A total of 255 ABC (205 in remote, 50 in urban locations) and 76 TEC members participated. Median aldosterone concentration was similar for all three groups. The median renin concentration was 7.5 mU/L (interquartile range [IQR], 4.1-12.4 mU/L) in the TEC group, 12.4 mU/L (IQR, 5.1-19 mU/L) in the urban ABC group, and 29.3 mU/L (IQR, 15.0-52.9 mU/L) in the remote ABC group. The median ARR was 10 pmol/mU (IQR, 6-19 pmol/mU) in the remote ABC group, 28 pmol/mU (IQR, 16-70 pmol/mU) in the urban ABC group, and 43 pmol/mU (IQR, 26-74 pmol/mU) in the TEC group. Thirteen urban ABC participants (26%), 21 TEC participants (28%), and six people in the remote ABC group (3%) had ARR values above 70 pmol/mU. Adjusted for age and body mass index (BMI), mean systolic and diastolic blood pressure were lower for women than men in all participant groups; after adjusting for age, sex, and BMI, larger ARR was associated with higher systolic blood pressure in the TEC group but not the two ABC groups.

CONCLUSION

Screening test results for primary aldosteronism were positive for about one-quarter of urban Indigenous and non-Indigenous participants. A prospective study that includes confirmatory testing would more accurately assess the prevalence of primary aldosteronism among Indigenous Australians in the Northern Territory.

Effect of Oral Contraception on Screening Tests for Primary Aldosteronism: A 10-Year Longitudinal Study

CONTEXT

Primary aldosteronism (PA) and oral contraception (OC) can both cause hypertension in young women. However, the effect of OC on the screening test for PA, the aldosterone to renin ratio (ARR), is not clear.

OBJECTIVE

We evaluated the impact of OC on the screening test for PA.

METHODS

In this retrospective cohort study, we analyzed data from the female offspring (Gen2) of women enrolled in the Raine Study, a population-based birth cohort, who had blood pressure (BP) measurements, blood samples, and information about OC use at age 17 years (N = 484) and/or age 27 years (N = 486).

RESULTS

Aldosterone concentration was significantly higher in OC users than nonusers at 17 years (median 486 pmol/L vs 347 pmol/L, P < 0.001). Renin concentration was significantly lower in OC users at both 17 years (13.4 mU/L vs 20.6 mU/L) and 27 years (9.2 mU/L vs 11.8 mU/L), hence the ARR was significantly higher in OC users compared to nonusers at both 17 years (31.5 vs 18.3) and 27 years (27.3 vs 21.1). The proportion of participants with ARR > 70 pmol/mU (current threshold for PA detection) was significantly higher in OC users at both 17 years (12.6% vs 2.1%) and 27 years (6.4% vs 0.4%); however, they had comparable BP to those with ARR < 70. OC use at any age abolished the relationship between ARR and BP that is observed in nonusers.

CONCLUSION

OC can increase the ARR and cause a false positive PA screening result. Until more reliable criteria for PA screening in OC users are established, alternative contraception should be considered during screening.

Renin, aldosterone, the aldosterone-to-renin ratio, and incident hypertension among normotensive subjects from the general population

AIMS

To investigate the predictive ability of direct plasma renin and aldosterone concentrations as well as their ratio [aldosterone-to-renin (ARR)] for incident hypertension in the general population.

METHODS AND RESULTS

Concentration of renin and aldosterone were measured by a chemiluminescence immunoassay using the fully automated LIAISON® platform (DiaSorin) among 5362 participants of the population-based Gutenberg Health Study, who were normotensive and had no clinically overt cardiovascular disease at baseline. During a follow-up period of 5 years, 18.6% (n = 996) developed a new-onset hypertension. Comparing extreme quartiles of biomarker distribution, the relative risk (RR) for incident arterial hypertension was found to be 1.58 [95% confidence interval (CI) 1.25-2.00; P = 0.00015; Q1 vs. Q4ref] for renin; 1.29 (95% CI 1.05-1.59, P = 0.018; Q4 vs. Q1ref) for aldosterone and 1.70 (95% CI 1.33-2.12; P < 0.0001; Q4 vs. Q1ref) for ARR after multivariable adjustment in men. In females, only high ARR was independently predictive for incident hypertension over 5 years [RR 1.29 (95% CI 1.04-1.62); P = 0.024]. Even in the subgroup of individuals having biomarker concentrations within the reference range, high ARR was predictive for new-onset hypertension in men [RR 1.44 (95% CI 1.13-1.83); P = 0.003]. Finally, synergistic effects of co-prevalent obesity and ARR on incident hypertension were also demonstrated, resulting in markedly higher risk estimates as seen for biomarker alone [RR of 2.70 (95% CI 2.05-3.6) for Q4 of ARR and having body mass index ≥ 30 kg/m2 vs. low ARR (Q1ref) and normal weight; P < 0.0001].

CONCLUSION

Among normotensives from the general population ARR possesses a stronger predictive value for incident hypertension than renin or aldosterone alone. The prediction of arterial hypertension by ARR was even stronger in obese subjects.

Aldosterone, Renin, and Aldosterone-to-Renin Ratio Variability in Screening for Primary Aldosteronism

CONTEXT

The plasma aldosterone concentration (PAC), renin, and aldosterone-to-renin ratio (ARR) are used to screen for primary aldosteronism (PA). Substantial intra-individual variability of PAC and ARR using plasma renin activity in the context of usual antihypertensive therapy has been described, but there is no data on ARR variability calculated using direct renin concentration (DRC).

OBJECTIVE

To describe the intra-individual variability of PAC, DRC, and ARR in the absence of interfering medications in patients with and without PA.

DESIGN

Retrospective cohort study.

PATIENTS

Hypertensive patients referred for investigation of PA, with at least 2 ARR measurements while off interfering medications.

SETTING

Endocrine hypertension service of a tertiary center, from May 2017 to July 2021.

MAIN OUTCOME MEASURES

PAC, DRC, and ARR variability was calculated as coefficient of variation (CV) and percent difference (PD).

RESULTS

Analysis of 223 patients (55% female, median age 52 years), including 162 with confirmed PA, demonstrated high variability with a sample CV of 22-25% in the PAC and sample CV of 41% to 42% in the DRC and ARR in both the PA and non-PA groups. The degree of variability was substantially higher than the assays' analytical CV. Sixty-two patients (38%) with PA had at least one ARR below 70 pmol/L:mU/L (2.4 ng/dL:mU/L), a cut-off for first-line screening of PA.

CONCLUSIONS

Significant intra-individual variability in PAC, DRC, and hence ARR occurs in a large proportion of patients being investigated for PA. These findings support the need for at least 2 ARR before PA is excluded or further investigated.