Factors related to suboptimal recovery of renal function after living donor nephrectomy: a retrospective study

Background The renal function of the remaining kidney in living donors recovers up to 6070% of pre-donation estimated-glomerular filtration rate (eGFR) by compensatory hypertrophy. However, the degree of this hypertrophy varies from donor to donor and the factors related to it are scarcely known. Methods We analyzed 103 living renal transplantations in our institution and divided them into two groups: compensatory hypertrophy group [optimal group, 1-year eGFR >= 60% of pre-donation, n = 63] and suboptimal compensatory hypertrophy group (suboptimal group, 1-year eGFR < 60% of pre-donation, n = 40). We retrospectively analyzed the factors related to suboptimal compensatory hypertrophy. Results Baseline eGFRs were the same in the two groups (optimal versus suboptimal: 82.0 +/- 13.1 ml/min/1.73m(2) versus 83.5 +/- 14.8 ml/min/1.73m(2), p = 0.588). Donor age (optimal versus suboptimal: 56.0 +/- 10.4 years old versus 60.7 +/- 8.7 years old, p = 0.018) and uric acid (optimal versus suboptimal: 4.8 +/- 1.2 mg/dl versus 5.5 +/- 1.3 mg/dl, p = 0.007) were significantly higher in the suboptimal group. The rate of pathological chronicity finding on 1-h biopsy (ah >= 1 boolean AND ct + ci >= 1) was much higher in the suboptimal group (optimal versus suboptimal: 6.4% versus 25.0%, p = 0.007). After the multivariate analysis, the pathological chronicity finding [odds ratio (OR): 4.8, 95% confidence interval (CI): 1.3-17.8, p = 0.021] and uric acid (per 1.0 mg/dl, OR: 1.5, 95% CI: 1.1-2.2, p = 0.022) were found to be independent risk factors for suboptimal compensatory hypertrophy. Conclusion Chronicity findings on baseline biopsy and higher uric acid were associated with insufficient recovery of the post-donated renal function.