Aim: To determine whether mass screening for proteinuria may be worthwhile in the detection of early renal disease in Australians.
Methods: A feasibility study was conducted using systematic review, meta-analysis and cost-effectiveness methods.
Results: End-stage renal disease (ESRD) develops in about 1500 Australians each year. Of these, about 1000 are over 50 years of age (an incidence of about 200 per million, per year). Proteinuria, which is present in about 5% of the general population, confers an approximately 15-fold increased risk for ESRD. Twelve randomized trials of angiotensin-converting enzyme inhibitors (ACEi), in 1943 patients with varying degrees of renal impairment, hypertension and proteinuria, showed that the risk of developing ESRD can be reduced by about 30% over a 2- to 3-year period. In a general-practice-based screening model involving: (i) an opportunistic single dipstick test for protein, (ii) a confirming 24-h urine test for protein and (iii) commencement of ACEi in appropriate individuals, 20 000 people over 50 years of age would need to be screened to prevent one case of ESRD. To achieve this, approximately 100 people would need to be treated with ACEi for 2 to 3 years, and 1,000 would need to have a 24-h urine protein test (and of these, 700 would be false positives). Such a strategy may save health dollars but some critical research questions are still unanswered. What is an individual's risk of developing ESRD, given values for proteinuria, blood pressure and renal function? What is the benefit of ACEi in screen-detected cases, which are at low risk of ESRD? What psychological and physical harm is caused by screening, including the specific renal investigations and treatments that follow on from proteinuria detection?
Conclusions: Given available data, screening middle-aged and older Australians for proteinuria and treating some with ACEi is, at best, a promising primary prevention strategy for preventing ESRD. However, a large population-based cohort study, with nested trial of ACEi, is still required to evaluate whether this model of screening for renal disease does more harm than good.