Department of Innovative Research and Education for Clinicians and Trainees (DiRECT), Fukushima Medical University Hospital, Fukushima, Japan; Institute for Health Outcomes and Process Evaluation Research (iHope International), Kyoto, Japan.
Department of Healthcare Epidemiology, School of Public Health in the Graduate School of Medicine, Kyoto University, Kyoto, Japan; Department of Endocrinology, Tenri Hospital, Tenri City, Nara, Japan.
J Ren Nutr. 2017 Nov;27(6):421-429. doi: 10.1053/j.jrn.2017.05.003. Epub 2017 Jun 17.
The dialysis practice guideline in Japan sets a limit on the allowed interdialytic weight gain (IDWG) <6%. However, the effects of relative gain of fluid volume to body weight may differ in presence of morbid conditions. Here, we examined whether or not the associations between IDWG and mortality differ by serum albumin (sAlb), a nutritional and illness marker.
The study type used was prospective cohort study.
Patients who participated in the Japan Dialysis Outcomes and Practice Pattern Study (phase 1-4 [1999-2011]) and received thrice-weekly hemodialysis.
IDWG was the exposure of interest and was collected every 4 months, divided into 7 categories as follows: <2%, 2% to 3%, 3% to 4% (reference), 4% to 5%, 5% to 6%, 6% to 7%, and >7%. sAlb was treated as both an effect modifier and confounder and dichotomized into ≥3.8 g/dL and <3.8 g/dL segments, according to the protein-energy wasting criteria proposed by the International Society of Renal Nutrition and Metabolism.
The outcome in this study was all-cause mortality.
A total of 8,661 patients were analyzed. Time-varying Cox regression analyses revealed that, when sAlb was ≥3.8 g/dL, an IDWG >7% was associated with greater risk of mortality (adjusted hazard ratio [AHR] 2.74; 95% confidence interval [CI], 1.49-5.05). When sAlb was <3.8 g/dL, however, IDWGs <2% (AHR 1.89; 95% CI, 1.50-2.39) and 4% to 5% (AHR 0.75; 95% CI, 0.58-0.96) were associated with mortality (P for interaction = .001). Cubic spline analyses showed that the mortality increased when IDWG exceeded 6% for patients with sAlb ≥3.8 g/dL; in contrast, for patients with sAlb <3.8 g/dL, the mortality increased when IDWG was <3% and decreased when IDWG was between 4% and 6%.
The main limitation was possible residual confounding.
The direction and magnitude of the associations between IDWG and mortality were modified by sAlb. Dialysis experts should take these results into account when revising the clinical practice guidelines.
日本的透析实践指南规定，允许的透析间体重增加（IDWG）<6%。然而，在存在病态情况下，液体量相对于体重的增加的效果可能不同。在这里，我们研究了 IDWG 与死亡率的关联是否因血清白蛋白（sAlb）而不同，sAlb 是一种营养和疾病标志物。
本研究类型为前瞻性队列研究。
参加了日本透析结局和实践模式研究（第 1-4 阶段[1999-2011]）并接受每周三次血液透析的患者。
IDWG 是本研究的暴露因素，每 4 个月采集一次，分为 7 类：<2%、2%至 3%、3%至 4%（参考）、4%至 5%、5%至 6%、6%至 7%和>7%。sAlb 既作为效应修饰剂，也作为混杂因素进行处理，并根据国际肾脏营养与代谢学会提出的蛋白质能量消耗标准，将其分为≥3.8g/dL 和<3.8g/dL 两个段。
本研究的结局是全因死亡率。
共分析了 8661 名患者。时变 Cox 回归分析显示，当 sAlb≥3.8g/dL 时，IDWG>7%与更高的死亡风险相关（调整后的危险比 [AHR] 2.74；95%置信区间 [CI]，1.49-5.05）。然而，当 sAlb<3.8g/dL 时，IDWG<2%（AHR 1.89；95%CI，1.50-2.39）和 4%至 5%（AHR 0.75；95%CI，0.58-0.96）与死亡率相关（交互作用 P 值<.001）。三次样条分析显示，当 sAlb≥3.8g/dL 时，IDWG 超过 6%时死亡率增加；相反，当 sAlb<3.8g/dL 时，IDWG<3%时死亡率增加，IDWG 在 4%至 6%之间时死亡率降低。
主要的局限性是可能存在残余混杂。
IDWG 与死亡率之间的关联方向和程度受到 sAlb 的修饰。当修订临床实践指南时，透析专家应考虑这些结果。
