The costs and benefits of automatic estimated glomerular filtration rate reporting

Abstract

Background and objectives: The prevalence of chronic kidney disease (CKD) has increased over the past two decades. The sensitivity of serum creatinine (sCr) to identify CKD is low. As a result, many healthcare centers report estimated GFR (eGFR) with routine blood work. The aim of this study was to determine the cost-effectiveness of automatic eGFR reporting compared with reporting sCr alone.

Design, setting, participants, & measurements: A Markov model was designed to evaluate the cost-effectiveness of reporting eGFR compared with reporting sCr alone in a hypothetical cohort of 60-yr-old individuals undergoing annual blood chemistry testing over 18 yr. Paths and path probabilities were identical between the two arms, except for the sensitivity and specificity of eGFR and sCr to detect CKD.

Results: eGFR reporting was dominant with a cost/effectiveness ratio of $16,751/quality-adjusted life year (QALY) versus $16,779/QALY for sCr reporting. Monte Carlo microsimulations in a hypothetical cohort of 10,000 patients demonstrated that over 18 yr, an average of 13 fewer deaths, 29 fewer ESRD events, and 11,348 more false positive CKD (FP-CKD) cases occurred with eGFR reporting. A sensitivity analysis revealed that decreasing the FP-CKD quality of life by > 2% rendered sCr reporting more cost-effective than eGFR reporting. If FP-CKD reduced quality of life by 5%, the incremental cost-effectiveness ratio for sCr reporting versus eGFR reporting would be $4367/QALY.

Conclusion: 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.

Figure 1.

State transition model showing the possible transitions of patients between health states. An individual patient could be in only 1 of the 6 possible states during a single cycle. TN-CKD, true negative state for patient without chronic kidney disease (GFR ≥ 60 ml/min/1.73 m²); FP-CKD, false positive state for patient without chronic kidney disease; TP-CKD, true positive state for patient with chronic kidney disease; FN-CKD, false negative state for patient with chronic kidney disease; CKD, chronic kidney disease stages 3 to 4 (GFR 15 to 59 ml/min/1.73 m²); ESRD, end stage renal disease (GFR < 15 ml/min/1.73 m²).

Figure 2.

One-way sensitivity analysis of quality of life assigned to the state of false positive chronic kidney disease (FP-CKD). Estimated GFR and serum creatinine reporting strategies are compared with effectiveness (QALYs) as the measured outcome.

Figure 3.

One-way sensitivity analyses of three variables. (a) Quality of life adjustment for patients with false positive diagnosis of CKD. (b) Annual probability of progressing from CKD to ESRD. (c) Sensitivity of serum creatinine to identify CKD. Estimated GFR and serum creatinine reporting strategies are compared with cost-effectiveness (dollars/quality adjusted life year) as the measured outcome. Base case results: eGFR $16,751/QALY, serum creatinine $16,779/QALY; eGFR dominates. CKD, chronic kidney disease stages 3 to 4 (GFR 15 to 59 ml/min/1.73 m²); ESRD, end stage renal disease (GFR < 15 ml/min/1.73 m²).

Figure 4.

Monte Carlo probabilistic analysis, results of 1000 trials plotting incremental cost versus incremental effect. eGFR reporting is compared with the baseline strategy of serum creatinine reporting. QALY, quality-adjusted life year