Assessment of different threshold preoperative glomerular filtration rates as markers of outcomes in lung transplantation.

BACKGROUND: The evidence behind the widely used pre-lung transplant glomerular filtration rate (GFR) cutoff of 50 mL/min per 1.73 m2 is limited. This study reviews data from a large cohort to assess outcomes associated with this historical cutoff and to estimate other possible cutoffs that might be appropriate in lung transplantation.
METHODS: We conducted a retrospective cohort analysis of lung recipients at a single center. Recursive partitioning and receiver operating characteristics analysis were used to estimate other potential GFR cutoffs with 1-year mortality as the outcome. Postoperative outcomes around the various cutoffs, including survival, acute kidney injury, and dialysis, were assessed using χ2, Kaplan-Meier, and Cox regression methods.
RESULTS: A total of 794 lung recipients met study inclusion criteria. Compared with 778 patients with GFR 50 mL/min per 1.73 m2 or greater at time of transplant, 16 patients with GFR below this cutoff were older and more likely to have restrictive disease. One-year mortality below the cutoff was 31.3% compared with 15.1% above the cutoff (p=0.021). Recursive partitioning estimated potential GFR cutoff values between 46 and 61 mL/min per 1.73 m2. Patients with GFR below these cutoffs were at significantly higher risk for adverse outcomes (p<0.05). Receiver operating characteristics analysis was less successful at identifying meaningful cutoff values with areas under the curve approximately 0.5.
CONCLUSIONS: Study results support the practice of requiring candidate GFR 50 mL/min per 1.73 m2 or greater for lung transplantation. Future work should focus on reproducing the analysis in a larger cohort of patients including more individuals with low GFR.