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OBJECTIVES To determine the extent to which metabolic and inflammatory changes are associated with renal damage beyond conventional risk factors in a community sample with a high prevalence of obesity in urban South Africa. METHODS This was a cross-sectional, community-based study in 1 010 (n = 872 without diabetes mellitus, DM) randomly selected participants over 16 years of age in an urban, developing community (Soweto, Johannesburg) with a high prevalence of obesity (41.8%). We assessed estimated glomerular filtration rate (eGFR), conventional risk factors including adiposity indices, and metabolic changes and plasma resistin concentrations (ELISA) and the homeostasis model of insulin resistance (HOMA-IR). Relationships independent of haemodynamic loads were confirmed using ambulatory blood pressure and central arterial haemodynamics. RESULTS In multivariate regression models conducted in those without DM, HOMA-IR (standardised β-coefficient = -0.13 ± 0.03, p < 0.0001) and plasma resistin concentrations (β-coefficient = -0.10 ± 0.02, p < 0.0001) were second only to age, and at least as strong as systolic blood pressure (β -coefficient = -0.04 ± 0.03, p = 0.19) in the impact on eGFR, while alternative conventional risk factors including adiposity indices and the metabolic syndrome features contributed little to eGFR. Similar results were obtained in relationships with chronic kidney disease (CKD) and in the whole group including those with DM. Adjustments for ambulatory blood pressure or central arterial loads did not influence these relationships. CONCLUSIONS The impact on glomerular function of insulin resistance and inflammatory changes is well beyond modifiable conventional risk factors, including the metabolic syndrome. Targeting conventional risk factors alone is likely to result in a marked residual risk of renal damage produced by insulin resistance and inflammation.

Objectives One year of antihypertensive therapy may normalise left ventricular (LV) structure in 51% of hypertensive patients of European descent. Whether similar effects can be achieved in patients of African descent, who have a high prevalence of concentric LV hypertrophy (LVH) and remodelling, is unknown. Methods In 103 hypertensive patients in the Baragwanath Hypertension study we evaluated the prevalence of residual LV structural changes (echocardiography) after four and 13 months of stepwise antihypertensive therapy. Results After 13 months of therapy, 24-hour blood pressure control was achieved in 47% of patients. At baseline, 51.5% of patients had concentric LVH, 19% eccentric LVH and 12% concentric LV remodelling. Despite changes in LV mass index (p < 0.01) and relative wall thickness (p < 0.05) with treatment, the proportion of patients with a normal LV mass or geometry increased only from 17.5 to 25% (p > 0.05), while 26% remained with concentric LVH (p < 0.001 compared to baseline), 25% with eccentric LVH and 23% with concentric LV remodelling (p < 0.05 compared to baseline). Residual structural changes were associated with 24-hour pulse pressure (p = 0.02), but not with 24-hour systolic or diastolic blood pressure or clinic blood pressure. Conclusions Even after a year of antihypertensive therapy, a high proportion (74%) of hypertensives of African ancestry retained residual LV structural changes, an effect that was associated with 24-hour pulse pressure but not systolic or diastolic blood pressures or clinic blood pressure in this ethnic group.