Correlation between body mass index and early recovery outcomes after kidney transplantation

doi:10.12307/2026.871

Abstract

Abstract: BACKGROUND: The proportion of obesity in the Chinese population has increased year by year, but its impact on early renal function recovery after kidney transplantation has not been systematically elucidated, and localized research is urgently needed to provide evidence-based basis.
OBJECTIVE: To investigate the effect of different body mass indexes on early renal function recovery in renal transplant recipients after surgery, to analyze the association between body mass index and postoperative creatinine, urine volume and hospital stay, and to propose clinical recommendations for individualized management.
METHODS: The clinical data of 495 renal transplant recipients in the Second Xiangya Hospital of Central South University from 2019 to 2020 were retrospectively analyzed. According to the Chinese obesity standard, they were divided into a lean group (body mass index < 18.5 kg/m2, n=78), a normal group (18.5 ≤ body mass index < 24 kg/m2, n=273), an overweight group (24 kg/m2 ≤ body mass index < 28 kg/m2, n=119), and an obese group (body mass index ≥ 28 kg/m2, n=25). The baseline characteristics, postoperative creatinine, urine volume, and hospital stay were compared among the groups. Multivariate regression analysis was used to analyze the independent effect of body mass index on postoperative recovery.
RESULTS AND CONCLUSION: (1) The age of the obese group was significantly higher than that of the other groups (P < 0.001), and the proportion of living donors was the lowest (0%, P=0.015). The creatinine level on the 1st day after surgery and hospitalization days were the highest (P < 0.001), and the urine volume was the lowest (P < 0.001). (2) Multivariate regression showed that for every 1 kg/m2 increase in body mass index, the creatinine level on the 1st day after surgery increased by 38 μmol/L (β=0.38, P < 0.001) and the urine volume decreased by 32 mL (β=-0.41, P < 0.001). These findings suggest that increased body mass index is an independent risk factor for slow early renal function recovery and prolonged hospital stay after kidney transplantation. Based on the Chinese obesity standard (body mass index ≥ 28 kg/m²), it is recommended to strengthen perioperative monitoring, optimize immunosuppression regimens, and develop individualized fluid management strategies for obese recipients to improve prognosis. This study provides evidence-based basis for the stratified management of body mass index tailored to local populations.

Key words: body mass index, kidney transplantation, postoperative recovery, creatinine, urine volume

CLC Number:

Zhong Xiaoping, Chen Dan, Xie Nianhua. Correlation between body mass index and early recovery outcomes after kidney transplantation[J]. Chinese Journal of Tissue Engineering Research, 2026, 30(34): 9002-9007.

Figures/Tables 5

2.5 术后肾功能恢复的体质量指数依赖性不同体质量指数受者的术后血肌酐水平差异如表3所示。根据体质量指数分组，偏瘦组、正常组、超重组及肥胖组的术后肌酐下降速度呈现显著递减趋势。非参数Kruskal-Wallis检验结果显示，术后各时间点及出院时的组间差异均有显著性意义(术后1 d：H=34.7，P < 0.001；术后5 d：H=18.2，P < 0.001；术后7 d：H=12.6，P=0.006；出院时：H=8.9，P=0.031)。数据表明，体质量指数较高的肾移植受者术后肌酐水平显著高于低体质量指数组，且随着体质量指数升高，术后肌酐恢复速度减缓，出院时肥胖组的肌酐值仍处于较高水平。这一结果进一步支持了体质量指数与术后肾功能恢复的负相关性，提示肥胖可能影响肾移植后代谢清除效率，需在临床管理中加强监测与干预。不同体质量指数受者的术后尿量差异如表4所示。偏瘦组、正常组、超重组及肥胖组的术后早期尿量呈现显著递减趋势。非参数Kruskal-Wallis检验结果显示，术后各时间点的组间差异均有显著性意义(术后1 d：H=22.4，P < 0.001；术后5 d：H=15.8，P=0.001；术后7 d：H=12.1，P=0.007)。数据表明，体质量指数较高的肾移植受者术后尿量显著低于低体质量指数组，且随着体质量指数升高，尿量减少的趋势持续至术后第7天。这一结果与前期发现的体质量指数与住院天数延长、肌酐水平升高的负相关性一致，提示肥胖可能影响术后肾功能恢复及体液代谢效率。 2.6 体质量指数对术后肌酐的独立影响在肾移植术后肌酐恢复的多因素回归分析中，体质量指数和术后尿量被确定为影响术后肌酐水平的关键独立因素，见表5。结果显示，体质量指数作为连续变量与术后各时间点肌酐水平呈显著正相关(术后1 d：β=0.38，P < 0.001；术后5 d：β=0.29，P=0.002；术后7 d：β=0.22，P=0.011；出院时：β=0.18，P=0.038)，表明体质量指数每增加1 kg/m2，术后肌酐水平相应升高。术后尿量则与肌酐水平呈显著负相关(术后1 d：β=-0.41，P < 0.001；术后5 d：β=-0.33，P < 0.001；术后7 d：β=-0.25，P=0.004；出院时：β=-0.19，P=0.021)，提示尿量增加可能通过改善体液代谢降低肌酐水平。其他显著影响因素有：①年龄在术后1 d对肌酐水平有正向影响(β=0.12，P=0.045)，但随着时间推移影响减弱；②未透析患者(vs.血透)在术后早期(1 d和5 d)与较低肌酐水平相关(β=-0.13，P=0.028；β=-0.11，P=0.049)；③糖尿病肾病(vs.慢性肾炎)显著增加术后1 d(β=0.15，P=0.018)和5 d(β=0.13，P=0.032)的肌酐水平；④住院天数在所有时间点均与肌酐水平正相关(术后1 d：β=0.21，P=0.003；出院时：β=0.11，P=0.049)，提示住院时间延长可能反映肾功能恢复延迟。非显著变量如性别、供体类型(活体捐献 vs. 死亡捐献)、人类白细胞抗原错配数及多数原发病类型(如高血压病、多囊肾)对肌酐水平的影响未达到统计学意义。模型整体解释力随时间递减(术后1 d R2=0.42，出院时R2=0.22)，表明术后早期肌酐水平更多受可量化因素影响，而后期可能受未观测变量(如个体代谢差异、"

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