Correlates of Abnormal Urinary Albumin Excretion Rates Among Primary Care Patients With Essential Hypertension

Abstract

Background: The excretion of small amounts of urinary protein, known as microalbuminuria, among patients with essential hypertension is associated with increased mortality from cardiovascular disease and, possibly, future renal decline. Correlates of microalbuminuria among primary care patients with essential hypertension, however, have not been well described.

Methods: One hundred forty patients enrolled in a large family practice ambulatory care center who had essential hypertension but not diabetes participated in a screening project to document cardiovascular and renal diseases in this population. Patients underwent a brief physical examination and submitted blood and urine samples for analysis.

Results: Twenty-five percent of patients had elevated urinary albumin excretion (UAE) rates, defined as greater than 30 μg/min. Patients with elevated UAE rates did not differ from patients without elevated UAE rates by age, race, sex, duration of hypertension, or type of antihypertensive medication used (if any). Although no patients had abnormally elevated g1ycosylated hemoglobin, after controlling for age and duration of hypertension, elevated UAE rates were significantly related to higher mean g1ycosylated hemoglobin levels (odds ratio [OR] = 3.06,95 percent confidence interval [CI] = 1.11 to 8.41) and to current smoking (OR = 3.14,95 percent CI = 1.09 to 9.04).

Conclusions: These data are the first in a primary care population to show a threefold increase in risk for elevated UAE rates among patients with essential hypertension who currently smoke or who have above-average g1ycosylated hemoglobin levels. Although cross-sectional in nature, these data can also point toward subgroups of hypertensive patients who have a worse cardiovascular prognosis.