van Manen Jeannette G, Korevaar Johanna C, Dekker Friedo W, Boeschoten Elisabeth W, Bossuyt Patrick M M, Krediet Raymond T
Department of Clinical Epidemiology, Dianet Dialysis Centres, University of Amsterdam, The Netherlands.
Am J Kidney Dis. 2002 Jul;40(1):82-9. doi: 10.1053/ajkd.2002.33916.
Many patients with end-stage renal disease (ESRD) have additional comorbid conditions. Differences in the presence and severity of these comorbid conditions can bias comparisons between treatment groups. Adjustment for prognostic factors can statistically counterbalance these differences. For this purpose, appropriate weighting of comorbid conditions is necessary. We evaluated three existing methods to score comorbidity in patients with ESRD and compared their ability to predict survival: the Khan, Davies, and Charlson indices. In addition, these three indices were compared with a new index that explicitly incorporates the severity grading of a number of comorbid diseases.
In a large Dutch prospective multicenter study (Netherlands Co-operative Study on the Adequacy of Dialysis-2), new patients with ESRD were included. Comorbidity was assessed at the start of dialysis therapy. Patient data were randomly allocated to a modeling or testing set. The new index was developed in the modeling set. All indices were evaluated in the testing set.
We obtained data for 1,205 patients. Of the three existing indices, the Charlson index had the best discriminating features, with a concordance c statistic of 0.71. The addition of severity grading of several comorbid conditions did not improve discrimination. After combining the comorbidity indices with age, all c statistics improved. These final values ranged from 0.72 to 0.75.
We conclude that the Khan, Davies, and Charlson scores are appropriate for expressing the prognostic impact of comorbidity on mortality risk in patients with ESRD provided sufficient adjustment for age is performed. Adding the severity grading of several comorbid conditions will not lead to improved prognostic power.
许多终末期肾病（ESRD）患者还伴有其他合并症。这些合并症的存在和严重程度差异可能会使治疗组之间的比较产生偏差。对预后因素进行调整可以在统计学上抵消这些差异。为此，有必要对合并症进行适当加权。我们评估了三种现有的ESRD患者合并症评分方法，并比较了它们预测生存的能力：汗氏指数、戴维斯指数和查尔森指数。此外，将这三种指数与一种明确纳入多种合并症严重程度分级的新指数进行了比较。
在一项大型荷兰前瞻性多中心研究（荷兰透析充分性合作研究-2）中，纳入了新的ESRD患者。在透析治疗开始时评估合并症。患者数据被随机分配到建模组或测试组。新指数在建模组中开发。所有指数在测试组中进行评估。
我们获得了1205例患者的数据。在三种现有指数中，查尔森指数具有最佳的区分特征，一致性c统计量为0.71。增加几种合并症的严重程度分级并没有改善区分能力。将合并症指数与年龄相结合后，所有c统计量均有所改善。这些最终值范围为0.72至0.75。
我们得出结论，汗氏、戴维斯和查尔森评分适用于表达合并症对ESRD患者死亡风险的预后影响，前提是对年龄进行了充分调整。增加几种合并症的严重程度分级不会提高预后能力。
