Abstract
Background and Aims
The prevalence of obesity has increased over the past decade in patients with End Stage Kidney Disease (ESKD). Obesity at the initiation of peritoneal dialysis (PD) was reported to adversely affect clinical outcomes. However, there are few studies on the prognostic relevance of weight gain after PD.
Method
We reviewed the change in body weight of 954 consecutive PD patients from the initiation of dialysis to 2 years after they remained on PD. Clinical outcomes including patient survival, technique survival, and peritonitis rate in the subsequent two years were reviewed.
Results
The mean age was 60.3 ± 12.2 years; 535 patients (56.1%) were men and 504 (52.8%) had diabetes. After the first 2 years on PD, the average change in body weight was 1.2± 5.1 kg; their body weight was 63.0 ± 13.3 kg; body mass index (BMI) 24.4 ± 4.4 kg/m2. The patient survival rates in the subsequent two years were 64.9%, 75.0%, and 78.9% (log rank test, p = 0.008) for patients with weight loss ≥3 kg during the first 2 years of PD weight change between -3 and +3 kg, and weight gain ≥3 kg, respectively. The corresponding technique survival rates in the subsequent two years were 93.1%, 90.1%, 91.3%, respectively (p = 0.110), and the peritonitis rates were 0.7±1.5, 0.6±1.7, and 0.6±1.1 episodes per patient-year, respectively (p = 0.3). When the actual BMI after the first 2 years of PD was categorized into underweight, normal weight, marginal overweight, overweight, and obesity groups, the patient survival rates in the subsequent two years were 77.3%, 75.2%, 73.3%, 74.3%, and 75.9%, respectively (p= 0.005), and technique survival 98.0%, 91.9%, 88.0%, 92.8%, and 81.0%, respectively (p= 0.001). After adjusting for confounding clinical factors by multivariate Cox regression models, weight gain ≥ 3kg during the first 2 years of PD was an independent protective factor for technique failure (adjusted hazard ratio [AHR] 0.049; 95% confidence interval [CI] 0.004-0.554, p = 0.015), but was an adverse predictor of patient survival (AHR 2.338, 95%CI 1.149-4.757, p = 0.019). In contrast, weight loss ≥ 3kg during the first 2 years of PD did not predict subsequent patient or technique survival.
Conclusion
Weight gain during the first 2 years of PD confers a significant risk of subsequent mortality but appears to be associated with a lower risk of technique failure. The mechanism of this discordant risk prediction deserves further study.
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