To the Editor: Dr Boulware and colleagues1 concluded that a strategy of annual dipstick screening for proteinuria with follow-up testing and treatment with an angiotensin-converting enzyme (ACE) inhibitor would not be cost-effective to slow progression of kidney disease or to decrease mortality. We believe that their results were strongly influenced by a number of factors, including the low yield of the screening test, the high costs for the screening by the primary care physician, and the possible added reduction of cardiovascular morbidity that is not taken into account.
Based on our data2 we think that screening for microalbuminuria would be more rational than screening for proteinuria. Among a primary prevention population, urinary albumin excretion of 0.3 g/dL or higher per 24 hours has been reported to be predictive for later occurrence of cardiovascular disease.2 - 3 Retrospective subgroup analyses of a recent large-scale randomized controlled trial found that treatment with ACE inhibitors is of particular value for preventing cardiovascular disease in high-risk patients with microalbuminuria (relative risk reduction, approximately 30%).4 We recently reported the results of a prospective, randomized, placebo-controlled trial in which an ACE inhibitor was found to reduce the combined end point of cardiovascular morbidity and mortality by 44% during 4 years of follow-up among normotensive, normocholesterolemic individuals with albuminuria.5
Because the incidence of proteinuria was less than 1% in the study by Boulware et al, their approach requires screening of many individuals to find 1 case. A large part of the screening costs in their analysis is therefore made to reimburse physicians for negative findings. Alternatively, in our study, persons aged 28 to 75 years were sent a 1-page questionnaire regarding demographics and a vial to collect an early morning urine sample. This vial and questionnaire were sent back to a central laboratory, where urinary albumin concentration was measured. Only those persons with a urinary albumin concentration of 0.1 g/dL or higher were asked to subsequently collect 24-hour urine specimens to detect a urinary albumin excretion of at least 0.3 g/dL per 24 hours, which is a method that we found to have a sensitivity of 88.9% and a specificity 80.1%. Using this approach, we found a 0.6% prevalence of proteinuria, similar to Boulware et al. However, the prevalence of microalbuminuria (urinary albumin excretion of 0.3-3 g/dL per 24 hours) was substantially higher (5.5%). The group with overt proteinuria may be evaluated for presence of renal disease and may benefit from treatment with ACE inhibitors not only for renoprotection, but also for cardioprotection. The group with microalbuminuria may be at risk for cardiovascular disease, and thus may also benefit from treatment.
Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature
Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal
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