Incidence of impaired renal function after lung transplantation

Abstract

Background: Impaired renal function is a frequent complication after lung transplantation (LTx). Since the early days of LTx, recipient eligibility criteria slowly became less strict, while treatment regimens evolved. These developments may have had opposing effects on the risk for impaired renal function. We aimed to study changes in recipient characteristics in conjunction with incidence of impaired renal function in consecutive series of lung transplant recipients (LTRs).

Methods: Three hundred forty adult LTRs (mean age 45 ± 12 years, 50.3% male, median follow-up 3.4 [1.0 to 7.1] years) were divided into four consecutive patient time-series: 1990 to 1996 (n = 93); 1997 to 2001 (n = 79); 2002 to 2005 (n = 89); and 2006 to 2008 (n = 79). The primary end-point was cumulative incidence of doubling of serum creatinine (DSC), taking into account the competing risk of death. Measured glomerular filtration rate (mGFR; (125)I-Iothalamate) was assessed as a secondary end-point.

Results: Mean age at transplantation (p = 0.001), prevalence of hypertension (p = 0.005), pack-years of former smoking (p = 0.001) and body mass index (p = 0.05) increased across the consecutive series. The cumulative incidence of DSC at 24 months after LTx was 43%, 37%, 35% and 29%, respectively, in the consecutive series (p = 0.01). Despite higher prevalence of renal risk factors, there was lower adjusted risk of DSC in the consecutive series, with hazard ratios [95% CI] of 0.62 [0.34 to 1.15], 0.50 [0.25 to 0.98] and 0.31 [0.154 to 0.67], respectively, compared with the 1990 to 1996 series. Accordingly, mGFRs at 24 months after LTx were 51 ± 17, 53 ± 17, 57 ± 21 and 63 ± 21 ml/min/1.73 m(2) in the consecutive series (p = 0.002).

Conclusions: Despite the higher prevalence of renal risk factors in more recently transplanted patients, renal outcome after LTx has improved over time. Nevertheless, impaired renal function remains a frequent complication after LTx.