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The tendency for Afro-American individuals with hypertension to retain salt and water can lead to low-renin hypertension. A prevalence study was conducted on the renin and aldosterone phenotype of a population with these characteristics in Colombia with the objective of establishing the standardization of cut-off points to make an accurate and timely diagnosis, identifying appropriate pharmacological therapy for controlling resistant arterial hypertension and investigating the relationship between sodium consumption and aldosterone and renin serum levels.
Afro-descendants who were ≥ 18 years old diagnosed with resistant hypertension and attending a primary care center in Colombia were recruited. Their serum levels of total renin and aldosterone concentration were measured and categorized as phenotypes into low renin and aldosterone phenotype, low renin and high aldosterone phenotype, and high renin and aldosterone phenotype, depending on the cutoff points used by Macchiavello et al. defining a low renin > 10 uU/mL and aldosterone < 6 pg/mL, Monticone S et al. defining low renin > 15 uUI/mL and aldosterone < 10 pg/mL. Furthermore, we conducted linear regression analyses for sodium intake and each adjusted model involving aldosterone, renin, and the aldosterone-renin ratio.
In this study, the results of 88 patients were analyzed. (mean age 56 [SD 12], 56% male). The results presented regarding the percentages of patients for each phenotype vary depending on the cutoff points used in the literature. The patients' sodium intake was found to be 8130 mg/day calculated using the Kawasaki formula. Notably, lower sodium intake is associated with higher renin (Beta = -0.75, p = 0.045) and higher aldosterone (Beta = -0.15, p = 0.013). However, no alteration was found in the direct renin-aldosterone relationship. Considering Macchiavello cutoffs the proportion of patients with Liddle phenotype is 15%, 51% with aldosteronism phenotype and 34% with renal phenotype. Taking into account Monticone cutoffs, 41% of patients have Liddle phenotype, 30% aldosteronism phenotype and 30% renal phenotype
The results presented regarding the percentages of patients for each phenotype vary depending on the cutoff points used in the literature. However, measurements are proposed to guide hypertension therapy in refractory arterial hypertension patients. Surprisingly, 38% of the patients are non-adherent to the treatment and we identified an underutilization of non-pharmacological treatment recommendations, such as sodium intake, as demonstrated in our study, which could have a significant impact on clinical outcomes. Moreover, the proportion of patients having a salt retaining state is about 66-71%. Further studies need to be conducted to evaluate diuretic response with mineralocorticoid antagonist and ENaC blockers, using these phenotypes and clinical outcomes.