What is the clinical evidence from this study?

Study design: Cross-Sectional. Population: Resistant hypertension (n=534). Intervention: Plasma aldosterone concentration and 24 h-urine aldosterone. Primary outcome: Apnea-hypopnea index (AHI) (β 0.32 for PAC, β 0.35 for 24h-urine aldosterone, p=<0.05).

March 22, 2017Open Access

Association of aldosterone excess and apnea-hypopnea index in patients with resistant hypertension

Q: What are the key findings of this study?

In patients with resistant hypertension, both plasma aldosterone concentration and 24-hour urine aldosterone levels were independently and positively associated with the apnea-hypopnea index.

Key Result

In patients with resistant hypertension, both plasma aldosterone concentration and 24-hour urine aldosterone levels were independently and positively associated with the apnea-hypopnea index.

Study Design

Type

Cross-Sectional (n=534)

Structured PICO

Is aldosterone excess associated with the severity of obstructive sleep apnea (AHI) in patients with resistant hypertension?

Population

534 adults aged 45-75 years with resistant hypertension underwent cross-sectional evaluation to assess the association between aldosterone levels and sleep apnea severity.

Outcome

Association of plasma aldosterone concentration (PAC) and 24 h-urine aldosterone levels with apnea-hypopnea index (AHI)surrogate

In patients with resistant hypertension, aldosterone excess is independently associated with the severity of obstructive sleep apnea.

Main Result

Effect estimate: β 0.32 for PAC, β 0.35 for 24h-urine aldosterone

p-value: p=<0.05

Limitations

Cross-sectional design precludes establishing causal relationships.
Small proportion of patients were treated with spironolactone during measurement, which might influence the relationship.
Participants were relatively healthy without overt cardiovascular or kidney disease, limiting generalizability to more morbid populations.

Abstract

The present study was to investigate the association of aldosterone excess and apnea-hypopnea index (AHI) in patients with resistant hypertension. Patients with resistant hypertension were enrolled and baseline characteristics including plasma aldosterone concentration (PAC) and 24 h-urine aldosterone levels were collected and compared between groups with different degrees of AHI as assessed by polysomnography. Association of key variables and AHI was then evaluated by univariate and multiple linear regression analysis. A total of 534 patients with resistant hypertension were enrolled and mean age was 57 ± 11 years. Overall, mean number of AHI was 21.7 ± 9.6 and nearly 92.3% of resistant hypertensive patients had obstructive sleep apnea (OSA). Mean PAC and 24 h-urine aldosterone level was 12.4 ± 6.3 ng/dL and 13.1 ± 6.8 ug, respectively. Compared with other groups, participants in the severe OSA group (AHI ≥ 30) had significantly higher PAC and 24 h-urine aldosterone level. Multiple linear regression analysis showed that PAC and 24 h-urine aldosterone levels were positively associated with AHI, while spironolactone was negatively associated with AHI, independent of age, gender, body mass index, smoking, plasma renin activity and diuretics. OSA is highly prevalent in patients with resistant hypertension and both PAC and 24 h-urine aldosterone level are significantly associated with AHI.

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