Secondary prevention of renal and cardiovascular disease: Results of a renal and cardiovascular treatment program in an Australian aboriginal community

Australian Aborigines are experiencing an epidemic of renal and cardiovascular disease. In late 1995 we introduced a treatment program into the Tiwi community, which has a three- to fivefold increase in death rates and a recent annual incidence of treated ESRD of 2760 per million. Eligible for treatment were people with hypertension, diabetics with micro or overt albuminuria, and all people with overt albuminuria. Treatment centered around use of perindopril (Coversyl, Servier), with other agents added to reach BP goals; attempts to control glucose and lipid levels; and health education. Thirty percent of the adult population, or 267 people, were enrolled, with a mean follow up of 3.39 yr. Clinical parameters were followed every 6 mo, and rates of terminal endpoints were compared with those of 327 historical controls matched for baseline disease severity, followed in the pretreatment program era. There was a dramatic reduction in BP in the treatment group, which was sustained through 3 yr of treatment. Albuminuria and GFR stabilized or improved. Rates of natural deaths were reduced by an estimated 50% (P = 0.012); renal deaths were reduced by 57% (P = 0.038); and nonrenal deaths by 46% (P = 0.085). Survival benefit was suggested at all levels of overt albuminuria, and regardless of diabetes status, baseline BP, or prior administration of angiotensin converting enzyme inhibitors (ACEI). No significant benefit was apparent among people without overt albuminuria, nor among those with GFR less than 60 ml/min. An estimated 13 renal deaths and 10 nonrenal deaths were prevented, with the number-needed-to-treat to avoid one terminal event of only 11.6. Falling deaths and renal failure in the whole community support these estimates. The program was extremely cost-effective. Programs like this should be introduced to all high-risk communities as a matter of urgency.

Plasma renin and aldosterone measurements in low renin hypertensive states

Plasma renin concentrations are extremely low, requiring high sensitivity methods to detect low renin hypertensive states. Moreover, plasma prorenin must not cryoactivate to renin to avoid falsely high values. The enzyme kinetic plasma renin activity (PRA) test has the required sensitivity, whereas direct renin assays and PRA tests with short incubation times are usually not accurate enough. Test specificity is essential for plasma aldosterone. The Nichols Advantage aldosterone assay is fast and automated but requires great attention to quality control. Here, the impact of renin on the aldosterone:renin ratio as a screening test for primary aldosteronism is reviewed. A sensitive plasma renin test is essential for the diagnosis of low renin hypertensive states and, currently, can be consistently achieved only with the PRA radioimmunoassay.