In the United States, 5.9% of the population has diabetes mellitus, and 800,000 people are given a diagnosis of this disease every year.1 Between 1990 and 1998 the age-adjusted prevalence of diabetes rose by 33%.2 It continues to affect younger people; since 1990 the United States experienced a 70% increase in the number of individuals aged between 30 and 39 years who were given the diagnosis of this chronic disease. Diabetes is the single most common cause of end-stage renal disease (ESRD), and ESRD rates continue to increase because of higher prevalence and longer life expectancies for people with type 2 diabetes.
Prevalence
Without interventions, 20% to 40% of type 2 patients with microalbuminuria eventually develop overt nephropathy, and it is estimated that 20% will have ESRD after 20 years.3 The clinical impact is seen in the frequency of treatment for new cases of ESRD from 1984 to 1996. It increased by 44% among persons younger than 45 years with diabetes, by 213% among those 45 to 64 years, by 405% among persons 65 to 74 years, and by 644% among those 75 years and older.4 Appropriate treatment can substantially reduce the incidence of nephropathy and the risk of acquiring other diabetes-related complications.5,6 However, the benefits of effective diabetes treatment will only be fully realized if preventive therapy is effectively integrated into clinical practice. Since the vast majority of patients with diabetes receive their care from a primary care physician, the focal point for the improvement of diabetes care should be the primary care office.7
Screening
Two articles in this month’s issue of JFP shed additional light on screening for microalbuminuria among people with diabetes. Scheid and colleagues8 systematically review the literature for evidence that screening for microalbuminuria prevents nephropathy in patients with diabetes. It is a short list of articles. The authors found no controlled trials of screening to prevent progression to nephropathy. It has only been in the last several years that good evidence has become available that treating microalbuminuria prevents progression to nephropathy in both type 1 and type 2 diabetes. The authors are asking a 2-part question: (1) How effective is screening for the detection of microalbuminuria? and (2) How effective is the treatment of microalbuminuria in the prevention of nephropathy? Evaluation of the evidence behind screening is incomplete without both answers. Although treatment of microalbuminuria is effective, the mechanics behind screening are complex. The authors raise an interesting challenge regarding the usefulness of repeating microalbumin tests to confirm the diagnosis of microalbuminuria. Repeating this test to reduce the error introduced by diurnal variation in the urine sample, as recommended by the American Diabetes Association, does not necessarily increase the predictive value. Although semiquantitative tests vary in accuracy with the specific gravity of urine (a variation that is substantially corrected for with quantitative tests), the authors note that the practical advantages of semiquantitative tests may outweigh their disadvantages. They call for a trial of different screening methodologies. They also remind us that much of what we do is based on expert opinion and is improved by closer evaluation of the specific recommendations.
The article by Hueston and colleagues9 is a sobering reminder of how, even in our training sites, we fail to institute clinical recommendations. In the 2 practices examined in this study, the rate of microalbumin testing was low. This was not because physicians were selectively screening only patients most likely to benefit and skipping those with proteinuria in whom testing may be less beneficial. Patients were not screened regardless of their risk and were often not started on angiotensin-converting enzyme (ACE) inhibitor therapy even with a positive screening result. I would suggest that the power of the study is misleading, since performing a microalbumin test is more likely a physician behavior than a patient characteristic. The likelihood of a patient having a microalbumin screen is probably nested within individual physician behavior and perhaps nested further within the 2 practices studied because of practice resources, laboratory availability, and similar practice patterns among faculty. It is also difficult to generalize how widespread this problem is. Still, it is an important step forward to recognize that clinical recommendations for microalbumin screening are not being followed within 2 residency practices and perhaps many more.
Preventive services
Of course, identifying the problem is only the first step. We must next take responsibility for improving the delivery of high-quality preventive services. Unfortunately this is not likely to be an easy task, such as the proposed consideration of recommending that everyone with diabetes be placed on an ACE inhibitor. There is very little evidence that patients with type 1 or type 2 diabetes who do not have hypertension and do not have microalbuminuria receive any patient-oriented improvement from long-term administration of ACE inhibitors. To suggest that population-based treatment of people with diabetes with ACE inhibitors would be cheaper or easier misses the point that as physicians we provide the best care for individuals and will (almost) never support the potential sacrifice of an individual’s well-being for societal benefits. Although streamlining the information flow of newly established evidence to daily practice will help, improved delivery of care will ultimately occur one physician at a time. I believe that the authors’ statement that “Since physicians do not screen reliably for fatal diseases with screening modalities that have been available for decades, it is unlikely that their behavior is likely to improve,” regrettably overlooks the enormous successes that have occurred in lipid management, cervical cancer, and breast cancer. Translating the latest recommendations into current practice will always be a struggle. But one of the strengths of family physicians is the continuing personal care that we can provide. Family physicians will not abandon the initiation of new preventive services and should not compromise personal care by treating populations at the expense of individuals.