Bohn Ethan, Tangri Navdeep, Gali Brent, Henderson Blair, Sood Manish M, Komenda Paul, Rigatto Claudio
University of Manitoba, Winnipeg, Canada.
BMC Nephrol. 2013 Dec 1;14:263. doi: 10.1186/1471-2369-14-263.
Clinical outcomes of dialysis patients are variable, and improved knowledge of prognosis would inform decisions regarding patient management. We assessed the value of simple, chest X-ray derived measures of cardiac size (cardiothoracic ratio (CTR)) and vascular calcification (Aortic Arch Calcification (AAC)), in predicting death and improving multivariable prognostic models in a prevalent cohort of hemodialysis patients.
Eight hundred and twenty-four dialysis patients with one or more postero-anterior (PA) chest X-ray were included in the study. Using a validated calcification score, the AAC was graded from 0 to 3. Cox proportional hazards models were used to assess the association between AAC score, CTR, and mortality. AAC was treated as a categorical variable with 4 levels (0,1,2, or 3). Age, race, diabetes, and heart failure were adjusted for in the multivariable analysis. The criterion for statistical significance was p<0.05.
The median CTR of the sample was 0.53 [IQR=0.48,0.58] with calcification scores as follows: 0 (54%), 1 (24%), 2 (17%), and 3 (5%). Of 824 patients, 152 (18%) died during follow-up. Age, sex, race, duration of dialysis, diabetes, heart failure, ischemic heart disease and baseline serum creatinine and phosphate were included in a base Cox model. Both CTR (HR 1.78[1.40,2.27] per 0.1 unit change), area under the curve (AUC)=0.60[0.55,0.65], and AAC (AAC 3 vs 0 HR 4.35[2.38,7.66], AAC 2 vs 0 HR 2.22[1.41,3.49], AAC 1 vs 0 HR 2.43[1.64,3.61]), AUC=0.63[0.58,0.68]) were associated with death in univariate Cox analysis. CTR remained significant after adjustment for base model variables (adjusted HR 1.46[1.11,1.92]), but did not increase the AUC of the base model (0.71[0.66,0.76] vs. 0.71[0.66,0.76]) and did not improve net reclassification performance (NRI=0). AAC also remained significant on multivariable analysis, but did not improve net reclassification (NRI=0). All ranges were based on 95% confidence intervals.
Neither CTR nor AAC assessed on chest x-ray improved prediction of mortality in this prevalent cohort of dialysis patients. Our data do not support the clinical utility of X-ray measures of cardiac size and vascular calcification for the purpose of mortality prediction in prevalent hemodialysis patients. More advanced imaging techniques may be needed to improve prognostication in this population.
透析患者的临床结局存在差异，对预后的深入了解有助于指导患者管理决策。我们评估了通过胸部X线片得出的简单心脏大小指标（心胸比（CTR））和血管钙化指标（主动脉弓钙化（AAC））在预测血液透析患者死亡及改进多变量预后模型方面的价值。
本研究纳入了824例有一张或多张后前位（PA）胸部X线片的透析患者。使用经过验证的钙化评分，将AAC分为0至3级。采用Cox比例风险模型评估AAC评分、CTR与死亡率之间的关联。AAC被视为具有4个水平（0、1、2或3）的分类变量。多变量分析中对年龄、种族、糖尿病和心力衰竭进行了校正。统计学显著性标准为p<0.05。
样本的中位CTR为0.53[四分位间距=0.48,0.58]，钙化评分如下：0级（54%）、1级（24%）、2级（17%）和3级（5%）。在824例患者中，152例（18%）在随访期间死亡。基础Cox模型纳入了年龄、性别、种族、透析时长、糖尿病、心力衰竭、缺血性心脏病以及基线血清肌酐和磷酸盐。CTR（每0.1单位变化的风险比（HR）为1.78[1.40,2.27]）、曲线下面积（AUC）=0.60[0.55,0.65]以及AAC（AAC 3级与0级相比HR为4.35[2.38,7.66]，AAC 2级与0级相比HR为2.22[1.41,3.49]，AAC 1级与0级相比HR为2.43[1.64,3.61]）、AUC=0.63[0.58,0.68]）在单变量Cox分析中均与死亡相关。调整基础模型变量后，CTR仍具有显著性（调整后HR为1.46[1.11,1.92]），但未增加基础模型的AUC（0.71[0.66,0.76]对比0.71[0.66,0.76]），也未改善净重新分类性能（NRI=0）。多变量分析中AAC也仍具有显著性，但未改善净重新分类（NRI=0）。所有范围均基于95%置信区间。
在这一透析患者队列中，通过胸部X线片评估的CTR和AAC均未改善对死亡率的预测。我们的数据不支持将X线心脏大小和血管钙化测量用于预测血液透析患者死亡率的临床实用性。可能需要更先进的成像技术来改善该人群的预后评估。
