NKF: Chronic Kidney Disease Often Missed in Primary Care

By Charles Bankhead
DALLAS, April 7 -- Chronic kidney frequently goes undiagnosed by primary care physicians, even in patients with clear risk factors, according to a study from the VA healthcare system.Medical records of two-thirds of patients with chronic kidney disease by estimated glomerular filtration rate had no evidence that the disease had been recognized, Grady Wick, M.D., of the University of Illinois at Chicago, reported at the National Kidney Foundation meeting here.Recognition improved with worsening kidney function.White patients and women had the lowest rates of detection.
"We found that recognition was pretty poor overall," said Dr. Wick. "Obviously, as [glomerular filtration rate] went down, the recognition rate went up. In the diagnostically nebulous area of a GFR of 50 or 60, recognition was only 18%."
To determine how often the condition is recognized in VA patients, he and his colleagues reviewed medical records of 354,468 patients seen at VA primary care clinics during 2002. They found that 78,563 patients had at least two estimated glomerular filtration rate values during the review period.
Chronic kidney disease was defined as an estimated rate <60 mL/min/1.732 on two occasions at least 90 days apart. Disease recognition was defined as the presence of a diagnostic code related to kidney disease or evidence of care by a nephrologist.
Of the patients with two estimated glomerular filtration rate measurements, 20,923 (26.6%) had chronic kidney disease. The investigators found evidence of disease recognition in 35.4% of cases.
The rate of recognition increased from 18.4% among patients with an estimated rate between 50 and 60 mL/min/1.732 to 92.2% for patients with an estimated rate <15 mL/min/1.732.
A separate analysis of disease recognition by serum creatinine level showed that the rate of recognition increased from 15.7% in patients with serum creatinine levels between 1.0 and 1.5 mg/dL to 90% among patients with creatinine levels ≥3.5 mg/dL.
Among patients with diabetes (25% of the population) or hypertension (50%), chronic kidney disease was recognized in 39% and 37%, respectively.
Recognition rates were 37% to 45% in patients with cardiovascular disease, peripheral vascular disease, a history of stroke, and chronic obstructive pulmonary disease.
Recognition rates differed substantially by race and sex. Primary care providers recognized chronic kidney disease in 55.7% of nonwhite patients versus 33.3% of white patients and in 35.9% of men versus 15.9% of women.
The rate of recognition did not differ between patients younger than 65 (37.6%) versus 65 or older (34.8%).
After adjustment for confounders, Dr. Wick and colleagues found that women were 66% less likely than men to have chronic kidney disease recognized by their primary care providers (OR 0.34, 95% CI 0.27 to 0.43). White patients were 57% less likely than black patients to have documentation of chronic kidney disease in medical records (OR 0.43, 95% CI: 0.39 to 0.47).
Dr. Wick said findings from a VA patient population might not be generalizable to other patient populations, but he acknowledged that that issue was beyond the scope of the study.
Dr. Wick reported no disclosures.
Primary source: National Kidney Foundation Meeting 2008Source reference:Fischer M, et al "Chronic kidney disease is significantly underrecognized among VA primary care users" NKF Meeting 2008; Abstract 218.