TY - JOUR
T1 - How to adjust for comorbidity in survival studies in ESRD patients: a comparison of different indices
AU - van Manen, Jeannette G.
AU - Korevaar, Johanna C.
AU - Dekker, Friedo W.
AU - Boeschoten, Elisabeth W.
AU - Bossuyt, Patrick M. M.
AU - Krediet, Raymond T.
PY - 2002
Y1 - 2002
N2 - BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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
AB - BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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
U2 - https://doi.org/10.1053/ajkd.2002.33916
DO - https://doi.org/10.1053/ajkd.2002.33916
M3 - Article
C2 - 12087565
SN - 0272-6386
VL - 40
SP - 82
EP - 89
JO - American Journal of Kidney Diseases
JF - American Journal of Kidney Diseases
IS - 1
ER -