Relationship between hypertension and serum anionic gap; A cross sectional study

The precise mechanisms underlying the pathogenesis of hypertension is not yet fully understood. However, higher production of organic acids and unmeasured anions has been suggested to increase the anionic gap and lead to the progression of hypertension. Limited investigations have been performed to clarify the association of hypertension with the anionic gap. In this study, we determined the relationship between the anionic gap and systolic and diastolic blood pressure.

In this cross sectional study, blood pressure of 88 hypertensive patients was measured by the standard method and the anionic gap was then calculated by measuring the serum sodium, chloride, and bicarbonate levels.

The mean age of patients was 62.68 ± 13.14 years old, and 53 patients (61.1%) were female. The mean systolic and diastolic blood pressures (SBP and DBP) were 141.87 and 83.54 mmHg, respectively. The mean anionic gap (AG) was 9.18. There was a direct and significant association between anionic gaps and SBP (P= 0.0001, r= 0.62), DBP (P= 0.01, r= 0.26) and mean arterial blood pressure (MAP) (P= 0.001, r= 0.49). The multivariate regression analysis showed that sodium levels and AG significantly predicted SBP, DBP and MAP.

Our findings indicates that increasing the production of endogenous organic acids and unmeasured anions might lead to increased AG, and consequently, increase in the rate of hypertension.