Validation of the cause of end-stage renal failure in Afro-Caribbean patients

Afro-caribbean patients are more frequently diagnosed than caucasians as having end-stage renal failure (ESRF) from primary hypertension or diabetic nephropathy. We performed a retrospective study to investigate the diagnostic criteria and to validate the causes of primary renal disease in all new cases of afro-caribbean patients with ESRF who commenced RRT at 3 inner city Hospitals (1991-1995). We collected clinical-pathological data using a standard proforma. Three of us validated the diagnoses. We have identified 142 afro-caribbean patients for inclusion in this study:mean age of 52.3 (15.50, 52.3 percent were male. Renal biopsy was performed in 32 percent of the patients. Before the validation ,the working diagnosis (including that submitted to EDTA) had been diabetic nephropathy 35.2 percent; primary hypertension 18.3 percent; "uncertain" cause 15.5 percent and primary glomerulonephritis 11.3 percent. Following the analysis we ascribed the underlying cause of ESRF to be: diabetic nephropathy 38.7percent (18.2 percent biopsy proven);"uncertain" 21.8 percent; primary glomerulonephritis 10.6 percent (100 percent bx proven); secondary glomerulonephritis 10.6 percent (66.6 percent bx proven); primary hypertension 10.6 percent (40 percent bx proven); pyelonephritis 3.5 percent; polycystic kidneys 2.8 percent. Among the "uncertain" (n=31): twenty four (17 percent) were related to long-standing hypertension but could not be proven as primary disease. Among the diabetic ESRF patients (n=55), only 6 had IDDM while 49 had NIDDM. Twenty percent (28/142) of all patients had accelerated hypertension while 95 percent (134/142) had hypertension at some time during their disease. This study shows that in afro-caribbean patients NIDDM is the main cause of ESRF, whilst the evidence of primary hypertension is over-estimated, the diagnosis is often made on inadequate criteria. Nevertheless primary hypertension plays an important role in progression to ESRF. (AU)