Biochemical Correlates Of Renal Dysfunction Among Non-Diabetic Hypertensives

Several prospective studies have identified hypertension and other conditions such as diabetes mellitus and cardiovascular diseases as strong independent risk factors for renal dysfunction. Little is however, known about the biochemical correlates of renal dysfunction among non-diabetic hypertensives. Moreover, hypertension has been identified as a major contributor to the high morbidity and mortality among African populations and these are sufficiently high to justify viewing the condition as a serious health problem. The overall aim of this study was to evaluate the biochemical correlates of renal dysfunction among non-diabetic, hypertensives. Parathyroid hormone (PTH) has been identified as the main regulator of calcium homeostasis and thus this study set out to evaluate the relationship between PTH and calcium among the study population. Further, this study sought to find out whether a correlation exists between anthropometry as well as blood pressure and the indicators of renal dysfunction among the study population. A total of 252 non-diabetic hypertensives were interviewed for enrolment into the study out of which 200 patients (volunteers) gave their voluntary consent for the study giving a response rate of 79.4%. Another 100 healthy subjects were also recruited as study controls.The results indicates that the prevalence of CKD using MDRD, CKD-EPI, CG-BSA and CG among the hypertensives were 43.0%, 46%, 47.5% and 50% respectively. The hypertensives had significantly higher waist and hip circumferences, they were also heavier and obese (based on their weight and body mass) compared to the control group. Furthermore, the hypertensives presenting with nephropathy were hypocalcaemic and excreted microalbumin as well as protein with none of the control group excreting either microalbumin or protein in the urine. Stratification between excretion of microalbumin and protein in the urine was 40.5% as against 16% respectively among the study subjects presenting with nephropathy. Significant increases were observed in serum concentrations of urea and creatinine (p <0.0001) whiles serum albumin decreased significantly (p <0.0001) among the hypertensives compared to the control group. Stratification of PTH among study participants and controls showed that serum PTH levels were higher among the study participants compared to the controls and as well increases as the severity of hypertension increases ( p <0.0001). The results also show significant increases in serum sodium (Na+) and chloride (Cl-) with lower levels of K+ among the hypertensive group compared to the control group. For every ml min-1 1.73m-2 decrease in eGFR (p <0.0001) as estimated by CG, CG-BSA, 4v-MDRD and CKD-EPI, there was a corresponding increase in both systolic and diastolic blood pressures (p <0.0001). Serum PTH, creatinine and urea increased where as serum calcium decreased significantly for every mmHg increase in both systolic and diastolic blood pressures (p <0.0001). The results of the study suggest that parathyroid hormone is linked with derangements in the metabolism of calcium as well as the severity of hypertension and hence may contribute to the development of secondary hyperparathyroidism.

Source: KNUST