Background: Little information exists regarding the rate of kidney functional loss after lung transplantation. The aim of this study was to assess the evolution of kidney function after lung transplantation, seeking to identify a pretransplant glomerular filtration rate (GFR) threshold under which dual lung-kidney transplantation should be considered.
Patients and methods: We performed a single-center, retrospective cohort study among patients who received a first lung transplant. GFR was measured with the MDRD7 equation immediately before and up to 10 years after transplantation. A hierarchical model of linear regression was used to determine the evolution of GFR over time.
Results: We studied 241 subjects whose mean GFR was 92 +/- 33 mL/min/1.73 m(2) immediately before transplantation. The GFR declined quickly during the first posttransplant month (-24 mL/min/1.73 m(2) vs baseline; 95% confidence interval [CI]: -27, -21 mL/min/1.73 m(2)). It decreased slightly between 1 and 12 months (-34 mL/min/1.73 m(2) at 12 months vs baseline; 95% CI: -37, -31 mL/min/1.73 m(2)) and then stabilized up to 10 years after transplantation. GFR loss varied according to the baseline GFR. In patients with baseline GFR < or = 60 mL/min/1.73 m(2), the GFR declined by 9 mL/min/1.73 m(2) (95% CI = 6-15) at 1 year and was stable there after.
Conclusion: GFR declines rapidly in the first month and at 1 year after lung transplantation, stabilizing thereafter. Because they are likely to develop eligibility for kidney transplantation in the 1 to 2 years following lung transplantation, we believe that dual lung-kidney transplantation should definitely be considered for subjects with a baseline GFR < or = 35 mL/min/1.73 m(2).