Automatic GFR Reporting Boosts First-Time Visits to Kidney Specialists

Megan Brooks

September 18, 2010

March 23, 2010 — Patient referrals to nephrologists increased by nearly 70% after introduction of routine reporting of moderately reduced estimated glomerular filtration rate (eGFR < 60 mL/min/1.73 m2), according to an article in the March 23/31 issue of the Journal of the American Medical Association.

The increase in referral rates was most pronounced in patients with more severe kidney dysfunction (eGFR < 30 mL/min/1.73 m2), "the group for whom current practice guidelines emphasize the value of timely nephrological referral," the study team notes. Referral rates also increased in women and the middle-aged to very old — 2 groups at increased risk for late detection of chronic kidney disease (CKD) — and in those with comorbid conditions such as hypertension or diabetes, who are at highest risk for adverse outcomes.

The author of an editorial accompanying the study emphasizes that the study "could not examine the relationship of these referrals with outcomes or cost."

In the study, researchers from the Alberta (Canada) Kidney Disease Network led by Brenda R. Hemmelgarn, MD, PhD, from the University of Calgary, used administrative healthcare and laboratory data for more than 1.1 million adults from the province of Alberta to analyze trends in nephrologist visits and healthcare resource use before and after routine eGFR reporting.

The investigators found that after a 3-month transition period following eGFR reporting (on October 15, 2004), the rate of first outpatient nephrologist visits for patients with CKD (eGFR < 60 mL/min/1.73 m2) increased by 17.5 (95% confidence interval [CI], 16.5 - 18.6; P < .001) visits per 10,000 patients with CKD per month. This represents a 68.4% relative increase from baseline (95% CI, 65.7% - 71.2%).

There was a "small but significant" decrease in the rate of change in new visits over time after eGFR reporting (P = .02), suggesting, the researchers say, that the magnitude of increase in referrals declined over time. Still, there was a sustained increase compared with the expected rate in the absence of eGFR reporting. For example, the increase in nephrologists visits in the first 24 months after reporting was 13.3 (95% CI, 9.1 - 17.4) visits per 10,000 patients with CKD per month, corresponding to a 61.7% (95% CI, 30.7% - 92.7%) relative increase.

In the subgroup of patients with eGFR of less than 30 mL/minute/1.73 m2, the rate of first visits to a nephrologist increased by 134.4 (95% CI, 60.0 - 208.7) visits per 10,000 patients per month after eGFR reporting.

The increase in referrals in this subgroup was predominately seen in women, those patients aged 46 to 65 years and aged 86 years and older, and those patients with hypertension, diabetes, and from 1 to 4 comorbid illnesses.

Implementation of routine eGFR reporting was not associated with increased rates of internal medicine or general practitioner visits. Nor did it lead to an increase in angiotensin-converting-enzyme inhibitor or angiotensin-receptor blocker use, "even among the subgroup with a proven clinical indication; namely, those with diabetes and proteinuria," Dr. Hemmelgarn and colleagues note.

"The association with estimated GFR reporting and long-term patient outcomes, as well as economic consequences, remains to be determined," they conclude.

In an editorial, Richard J. Glassock, MD, from the David Geffen School of Medicine at the University of California–Los Angeles, argues that, for a variety of reasons, the current estimated GFR-dominant formulation for defining and classifying CKD has many pitfalls and "requires an urgent overhaul."

Routine reporting of estimated GFR, he writes, "needs reconsideration (regardless of the formula used), and primary care physicians and nephrologists should work together to ensure that referrals for subspecialty care are timely and appropriate."

A new model that incorporates levels of albumin excretion in an estimated GFR-based matrix "have been advocated and it is likely that existing guidelines will be updated soon," Dr. Glassock notes.

"Much work," he concludes, "still needs to be done to achieve the proper balance between efficiently identifying the problem of actual CKD and minimizing the nuisance of both mislabeling CKD and unnecessary referral to a subspecialist."

This study was supported by the Alberta Heritage Foundation for Medical Research Interdisciplinary Team Grants Program and by the Kidney Foundation of Canada. The study authors have disclosed no relevant financial relationships.

JAMA. March 24/31, 2010;303:1151-1158, 1201-1203.

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