Stemming the tide: reducing cardiovascular disease and renal failure in Australian Aborigines

An epidemic of cardiovascular disease (CVD) and end stage renal disease (ESRD) has developed among Aborigines in the Northern Territory; CVD deaths increased over the 1980s (tripling among women!), and are now more than five times those of non-Aboriginal people, while ESRD rates are increasing more than 20-fold and are doubling every three to four years. Dialysis costs (>$75,000 per person/year) pose a crisis for health care budgets, but premature mortality is the greater human catastrophe. Health services are not meeting the challenge of timely diagnosis, prevention and containment. We screened 90% of adults (20+ years) in one community, with CVD mortality among the highest in Australia, and ESRD rates increased 60-fold. Seventy-five per cent of persons were smokers. Central obesity was common, but BMIs only modestly increased by Caucasian standards, 23% had hypertension (>140/90), 29% had diabetes or impaired glucose tolerance (IGT) (peaking at 65% of persons aged 40-49 years), high triglyceride and insulin levels were common, and 55% had albuminuria (albumin/creatinine ratio (ACR), >3.4 gm/moL). Progressive albuminuria predicted renal failure. ACR was correlated with age, BMI, blood pressure, lipid, glucose and insulin levels, heavy drinking and past and current skin infections, and, inversely with birth weight. ACR correlated strongly with a composite CV risk score, and in a two to five year follow-up, microalbuminuria (ACR 3.4-33) and overt albuminuria (ACR 34+) have both predicted increased rate of premature death from natural causes of lower ACRs. Thus albuminuria marks CV risk/disease. This implies that renal and CV disease share common risk factors, and should respond to the same interventions, and that this response might be monitored through ACR levels. Robust public health programmes could reduce all these reversible risk factors, lowering disease rates over the intermediate term, however, few such programmes are in place. Modification of disease in persons already afflicted is a parallel responsibility. To this end, in November 1995, we introduced a treatment programme with Coversyl (perindopril, Servier) for all persons in the study community with hypertension (>140/90), for all diabetics with ACR 3.4+ and for all nondiabetic, non-hypertensive persons with progressive overt albuminuria (ACR 34+). One-quarter of all adults, or 224 persons have enrolled; 162 have reached one year of treatment and 100 have passed two years. Compliance is reasonable and enthusiasm high. Average SBP has fallen 12 mmHg (24 mmHg in hypertensive persons), while average ACR and estimated glomerular filtration rate (GFR) have stabilised. This contrasts favourably with the pretreatment course (average 2.7 years) in the same persons, when SBP had increased by 3 mmHg, ACR had increased by 15% and GFR had decreased by 3.5 mL/min each year. Cautious estimates suggest a >50% fall in ESRD, and a reduction in all-cause and CV deaths, even at this early stage, although more extended observation is needed. These data predict a dramatic and rapid fall in morbidity, premature deaths and health care costs if these basic principles of medical care are extended to all Aboriginal people. A national, concerted, multi-disciplinary effort to implement a coherent, effective strategy to this end is of great urgency.