Automatic Estimated Glomerular Filtration Rate Reporting May Be of Limited Benefit

Laurie Barclay, MD

February 06, 2009

February 6, 2009 — Automatic estimated glomerular filtration rate (eGFR) reporting may be of limited benefit, according to the results of a study reported online January 28 in the Clinical Journal of the American Society of Nephrology.

"The prevalence of chronic kidney disease (CKD) has increased over the past two decades," write Julia R. den Hartog, MD, from the University of Virginia Health System in Charlottesville, and colleagues. "The sensitivity of serum creatinine (sCr) to identify CKD is low. As a result, many healthcare centers report [eGFR] with routine blood work."

The investigators used a Markov model to compare the cost-effectiveness of automatic eGFR reporting vs reporting sCr alone in a hypothetical cohort of individuals 60 years of age who underwent annual testing of blood chemistry for 18 years. Both groups had identical paths and path probabilities, except for the sensitivity and specificity of eGFR and sCr to identify CKD.

The cost/effectiveness ratio for eGFR reporting was $16,751/quality-adjusted life year (QALY) vs $16,779/QALY for sCr reporting. In a hypothetical cohort of 10,000 patients, Monte Carlo microsimulations showed that during 18 years, eGFR reporting was associated with an average of 13 fewer deaths, 29 fewer ESRD events, and 11,348 more false-positive CKD (FP-CKD) cases.

Sensitivity analysis showed that if FP-CKD reduced quality of life by more than 2%, then sCr reporting would be more cost-effective than eGFR reporting. The incremental cost-effectiveness ratio for sCr reporting vs eGFR reporting would be $4367/QALY if FP-CKD reduced quality of life by 5%.

"A decision analysis suggests that reporting eGFR may be beneficial, but this limited benefit was reversed with virtually any reduction in quality of life caused by incorrect diagnosis of CKD," the study authors write.

Limitations of this study include unavailability of precise estimates for some important variables, the assumption that both true-positive CKD and false-negative CKD have similar costs of care, unknown true prevalence of CKD in the elderly, and that the quality of life of CKD patients was assumed to be the same in the model whether or not CKD was diagnosed.

"Despite the widespread enthusiasm and increasing adoption of routine eGFR reporting, our study shows that clinicians and policy-makers should carefully examine the consequences of this practice," the study authors conclude. "Additional studies are needed to quantify the impact of false diagnosis of CKD on quality of life, the probability of progressing from CKD to ESRD, and the sensitivity with which serum creatinine and eGFR reporting alone identifies patients with CKD. Until these data become available, the superiority of eGFR reporting compared with serum creatinine alone remains uncertain."

Some of the authors report various financial relationships with the Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania, and/or the National Institutes of Health.

Clin J Am Soc Nephrol. Published online January 28, 2009.

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