OBJECTIVE: Our goal was to determine whether adult patients with type 2 diabetes who had gross proteinuria or were already taking angiotensin-blocking drugs were screened for microalbuminuria.
STUDY DESIGN: This was a retrospective cross-sectional study.
POPULATION: We included a total of 278 adult patients with type 2 diabetes seen during 1998 and 1999 at the family medicine practices of the Medical University of South Carolina.
OUTCOMES MEASURED: The outcomes were microalbuminuria testing during either 1998 or 1999 and the initiation of medication if the screening test result was positive.
RESULTS: We found that patients who could derive the greatest benefit from testing (ie, those without preexisting proteinuria or who were not receiving an angiotensin-blocking drug) were no more likely to be screened for microalbuminuria than those with existing proteinuria (16% vs 18%, P=.84) or those who were already being treated with an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker (16% vs 16%, P=.83). Also, when the microalbuminuria test result was positive, only 40% of the patients were placed on angiotensin-blocking drugs.
CONCLUSIONS: Physician use of microalbuminuria screening does not follow established guidelines. The test appears to be used for many patients who might not need to be screened, and it is not always used for patients who should be screened. Consideration should be given to other strategies to prevent nephropathy in persons with type 2 diabetes.
Nephropathy is one of the most common long-term side effects of diabetes mellitus and accounts for the largest percentage of patients requiring chronic renal dialysis in the United States and Europe.1,2 The high prevalence of type 2 diabetes among adults in the United States and the high rate of nephropathy in these individuals pose a great economic burden to the health care system.
Several studies have noted that angiotensin-converting enzyme inhibitors (ACEIs) can delay the progression of renal impairment in patients with type 2 diabetes.3-7 Patients with diabetic nephropathy generally progress from a stage of normal renal function to microalbuminuria, gross proteinuria, and then renal dysfunction.1 ACEIs appear to delay or prevent the progression from microalbuminuria to proteinuria. Although there are no controlled trials that show microalbuminuria screening as effective at reducing proteinuria, expert panels of the American Diabetes Association8 and National Kidney Foundation9 have recommended that patients with type 2 diabetes receive annual screening for microalbuminuria, and if it is detected on 2 of 3 occasions, these patients should be placed on an ACEI or an angiotensin receptor blocker (ARB) for renal protection.
Initial evaluation of data from primary care practices, however, reveals that screening for microalbuminuria is not optimal.10,11 One reason microalbuminuria screening may happen less often than expected could be that many patients with diabetes mellitus are already being treated with an ACEI or ARB for hypertension, congestive heart failure, or other reasons. Some physicians also might employ an ACEI or ARB prophylactically, starting treatment before recognizing microalbuminuria. Given that these patients are already being treated with an ACEI or ARB, clinicians may not recognize any usefulness in performing a microalbuminuria test.
The purpose of our study was to examine what patient factors are associated with screening for microalbuminuria in patients with type 2 diabetes mellitus. Specifically, we examined how often patients who were not screened were already being treated with an ACEI or ARB. Also, we hoped to characterize the populations being screened more fully to determine if certain patient and disease characteristics were associated with the likelihood of a screening test being performed. A better awareness of these characteristics will help in targeting specific patient groups and changing physician behavior.
Methods
Sample
Our sample was drawn from the primary care practice in the department of family medicine at the Medical University of South Carolina (MUSC) in 1998 and 1999. The department provided care for approximately 18,000 patients who made 42,000 and 48,000 patient visits in 1998 and 1999, respectively, at 2 clinical sites. These 2 sites serve a diverse population of patients in downtown Charleston and a nearby suburban area, which in 1998 had a payer mix distribution that was 26% Medicaid, 27% Medicare, 37% commercially insured, and 10% self-pay.
We identified patients with diabetes at the 2 clinical sites from a search of the problem list in an electronic medical record database that has been used in the department of family medicine since 1992 Table 1. All patients aged between 18 years and 65 years in 2000 and who had an appointment scheduled in 1998 or 1999 were included. The charts that were initially selected for review had diabetes mellitus listed as a problem; after the chart review, we excluded 18 patients from the study because they were using insulin or had not been seen in the practices since 1995, even though they had scheduled an appointment in 1998 or 1999. This left a final sample size of 278.