Is the plasma aldosterone-to-renin ratio associated with blood pressure response to treatment in general practice?

BACKGROUND: Individualized antihypertensive treatment based on specific biomarkers such as renin may lead to more effective blood pressure control in patients with newly diagnosed essential hypertension. Recent studies suggested that the plasma aldosterone-to-renin ratio (ARR) may also be a candidate predictor for this purpose. OBJECTIVE: To assess whether the ARR is associated with the blood pressure response to antihypertensive treatment in patients with newly diagnosed hypertension. METHODS: In this prospective cohort study in primary care, we determined the ARR in patients with newly diagnosed hypertension prior to starting treatment. Treatment was categorized in five groups: no medication, use of angiotensin-converting-enzyme inhibitor or angiotensin receptor blocker, use of calcium channel blocker, use of diuretic, or use of beta blocker. We examined the relation between the ARR and blood pressure response within 1 year of treatment, taking into account the type of antihypertensive treatment and adjusting for gender, age, baseline blood pressure, and comorbidity. RESULTS: Out of 304 patients, we used 947 measurements (727 no medication, 220 medication) for analysis. There was no association between the ARR and the response in blood pressure, and this applied to each treatment group. Target blood pressure, defined as systolic blood pressure <140 mmHg, was reached in 31% of patients. There was no association between the ARR and reaching target blood pressure (OR 1.002, 95% CI 0.983-1.022). CONCLUSION: The ARR is not associated with the response in blood pressure within 1 year of antihypertensive treatment in primary care.

Prevalence of primary aldosteronism in primary care: a cross-sectional study.

BACKGROUND: Primary aldosteronism (PA) is the most frequent cause of secondary hypertension. Reported prevalences of PA vary considerably because of a large heterogeneity in study methodology. AIM: To examine the proportion of patients with PA among patients with newly diagnosed, never treated hypertension. DESIGN AND SETTING: A cross-sectional study set in primary care. METHOD: GPs measured aldosterone and renin in adult patients with newly diagnosed, never treated hypertension. Patients with elevated aldosterone-to-renin ratio and increased plasma aldosterone concentration underwent a saline infusion test to confirm or exclude PA. The source population was meticulously assessed to detect possible selection bias. RESULTS: Of 3748 patients with newly diagnosed hypertension, 343 patients were screened for PA. In nine out of 74 patients with an elevated aldosterone-to-renin ratio and increased plasma aldosterone concentration the diagnosis of PA was confirmed by a saline infusion test, resulting in a prevalence of 2.6% (95% confidence interval = 1.4 to 4.9). All patients with PA were normokalaemic and 8 out of 9 patients had sustained blood pressure >150/100 mmHg. Screened patients were younger (P<0.001) or showed higher blood pressure (P<0.001) than non-screened patients. CONCLUSION: In this study a prevalence of PA of 2.6% in a primary care setting was established, which is lower than estimates reported from other primary care studies so far. This study supports the screening strategy as recommended by the Endocrine Society Clinical Practice Guideline. The low proportion of screened patients (9.2%), of the large cohort of eligible patients, reflects the difficulty of conducting prevalence studies in primary care clinical practice.

Study Heterogeneity and Estimation of Prevalence of Primary Aldosteronism: A Systematic Review and Meta-Regression Analysis.

CONTEXT: For health care planning and allocation of resources, realistic estimation of the prevalence of primary aldosteronism is necessary. Reported prevalences of primary aldosteronism are highly variable, possibly due to study heterogeneity. OBJECTIVE: Our objective was to identify and explain heterogeneity in studies that aimed to establish the prevalence of primary aldosteronism in hypertensive patients. DATA SOURCES: PubMed, EMBASE, Web of Science, Cochrane Library, and reference lists from January 1, 1990, to January 31, 2015, were used as data sources. STUDY SELECTION: Description of an adult hypertensive patient population with confirmed diagnosis of primary aldosteronism was included in this study. DATA EXTRACTION: Dual extraction and quality assessment were the forms of data extraction. DATA SYNTHESIS: Thirty-nine studies provided data on 42 510 patients (nine studies, 5896 patients from primary care). Prevalence estimates varied from 3.2% to 12.7% in primary care and from 1% to 29.8% in referral centers. Heterogeneity was too high to establish point estimates (I(2) = 57.6% in primary care; 97.1% in referral centers). Meta-regression analysis showed higher prevalences in studies 1) published after 2000, 2) from Australia, 3) aimed at assessing prevalence of secondary hypertension, 4) that were retrospective, 5) that selected consecutive patients, and 6) not using a screening test. All studies had minor or major flaws. CONCLUSIONS: This study demonstrates that it is pointless to claim low or high prevalence of primary aldosteronism based on published reports. Because of the significant impact of a diagnosis of primary aldosteronism on health care resources and the necessary facilities, our findings urge for a prevalence study whose design takes into account the factors identified in the meta-regression analysis.