Physicians May Miss Signs of Chronic Kidney Disease

BALTIMORE, July 31 -- A lot of primary care physicians need to bone up on the signs of chronic kidney disease, according to investigators here.

When randomly selected family practitioners and internists, were asked which diagnostic tests they would order for a hypothetical patient with symptoms and lab values consistent with chronic kidney disease, 59% of FPs and 78% of internists got it right, said L. Ebony Boulware, M.D., M.P.H., and colleagues, of Johns Hopkins.

This contrasted with 97% of nephrologists who got it right when asked the same questions.

"We, as physicians, can certainly do better," the investigators wrote in the August issue of American Journal of Kidney Diseases.

"Millions of people have kidney disease, but a substantial number may not have their disease recognized," they added. "Simply put, our study shows that primary care physicians are not recognizing kidney disease in high-risk patients as often as they should."

Using a list generated by the American Medical Association, the investigators mailed questionnaires to a random sampling of primary care physicians, general internists, and nephrologists. The questionnaires described a hypothetical patient on a new-patient visit, and asked what tests they would order and whether they would make referrals to a nephrologist at the visit.

The patient was described as a 50-year-old woman, 5'2" and 154 pounds. All physicians received the same description of the patient, with identical test values, signs, and symptoms, except for two patient characteristics, which varied to test the investigators' assumptions that certain factors could influence recommendations for further testing and referrals. The two characteristics were the patient's race, which could be either African American or Caucasian, and comorbidities, which could include hypertension alone or hypertension plus diabetes.

Clues pointing to a diagnosis of chronic kidney disease included persistent proteinuria over a four month period, and lab findings consistent with-but not spelled out as-with Kidney Disease Outcomes Quality Initiative (KDOQI) stage three chronic kidney disease progressing to stage 4 within four months.

The glomerular filtration rate was specified as progressing over four months from 30 to 59 mL/min/1.73 m² [0.50 to 0.98 mL/s] to 15 to 29 mL/min/1.73 m² [0.25 to 0.48 mL/s].

"Physicians were provided with enough clinical information in the scenario to use either the Cockroft-Gault or the modified Modification of Diet in Renal Disease equations to calculate the patient's estimated glomerular filtration rate themselves, but they were not provided with actual estimated glomerular filtration rate using either calculation," the authors noted.

The participants were also furnished with information about the patient's lab values from a previous visit to another physician four months earlier.

Respondents include 126 nephrologists (39% response rate), 89 FPs (28%), and 89 general internists (28%).

The investigators found that FPs recognized chronic kidney disease less often that either internists or nephrologists (adjusted percentage, 59%; 95% confidence interval, 47% to 69%).

More internists than FPs nailed the diagnosis (78%; 95% CI, 67% to 86%), as did an even higher percentage of nephrologists (adjusted percentage, 97%; 95% CI, 93% to 99%, P< 0.01).

In addition, while 76% and 81% of FPs and internists, respectively, said they would recommend referrals for the patient in the scenario, virtually all of the nephrologists (99%) would have done so, they reported.

"In this study of physicians sampled randomly from across the United States, our findings suggest that efforts to raise physicians' awareness of progressive chronic kidney disease and disseminate recently developed clinical practice guidelines have not been as effective as hoped," Dr. Boulware and colleagues wrote.

They also found that primary care physicians with more than 10 years of clinical practice experience were least likely to recognize chronic kidney disease and also least likely to recommend referral. The wrote that "these findings strongly confirm other studies indicating that more recently trained physicians are more aware of current treatment guidelines and potentially deliver better quality care."

They suggested that care of patients with chronic kidney disease could be enhanced through better dissemination of clinical practice guidelines, and better collaboration among primary care physicians and nephrologists, including joint practice guidelines focused on optimal diagnosis and management of patients with the condition. In addition, of the basis of their findings, they suggested that physicians with more years in practice should be targeted for dissemination of information regarding the identification and appropriate referral of patients with chronic kidney disease.

"Many of these primary care doctors are in absolutely the best position to diagnose and treat chronic kidney disease," said Neil R. Powe, M.D., of Johns Hopkins, a co-author.

"These health care professionals need to work with nephrologists to begin to eliminate the disagreement over how these patients should be treated and when they should be referred," he said.

They noted several limitations including the fact that the response rate was suboptimal, potentially limiting generalizability. In addition, they asked questions concerning a hypothetical patient rather than assessing actual practice behavior. However, they noted that several studies have shown that scenarios have been shown to have validity in quality of care assessment.