The purpose of this study is to compare two formulas for GFR estimation – the popular Modified Diet in Renal Disease, MDRD and the recently developed Chronic Kidney Disease Epidemiology Collaboration, CKD-EPI – based on their capacities for predicting outcomes in lung transplant recipients.

Methods: We conducted a retrospective study of lung recipients in a single institution. GFR was measured directly using intravenous nuclear Tc-99m DTPA. MDRD and CKD-EPI equations were used to estimate GFR based on serum creatinine measured close to the time of the nuclear study. Body surface area (BSA) adjusted and unadjusted values were estimated. Logistic regression was used to assess the effect of GFR on outcomes including mortality, kidney disease and acute rejection.

Results: Of 1050 patients in our cohort, 274 had results from the nuclear study and were included in this analysis. Mean GFR for the BSA-adjusted nuclear study was 84.7 ml/ (min*1.73m2). On univariate analysis, the BSA-unadjusted MDRD and CKD-EPI equations presented identical prediction profiles, predicting several outcomes including 30-day mortality, acute renal failure with creatinine greater than 3 mg/dL (ARF), CKD stage 3 and dialysis, all at p < 0.05. Relationships were significant on multivariate analysis, controlling for underlying diagnosis, age and preoperative comorbidities.

Overall, the BSA-unadjusted equations showed greater predictive capacity than their adjusted equivalents.

Conclusion: Despite concerns of poor GFR estimation by MDRD, the CKD-EPI and MDRD equations are equally predictive of early and late outcomes in lung recipients. Converting BSA-adjusted GFR to BSA-unadjusted GFR improves predictive utility of estimates. Surprisingly, the “gold-standard” nuclear GFR study did not contribute to risk stratification for patients.

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