Comorbidity index was successfully validated among men but not in women

ObjectiveTo validate the prognostic accuracy of a previously proposed comorbidity index using information of a different and separate population-based cohort.Study Design and SettingWe assessed the predictive accuracy of a comorbidity index to predict mortality by looking at calibration and discrimination in the development cohort as well as in a new cohort for validation. Calibration of the model was assessed by comparing predicted and current mortality in the new cohort by means of Hosmer–Lemeshow test (HL). Discrimination of the models was analyzed using the area under the receiver operating characteristic curves (ROC).ResultsIn the development cohort, we have not detected differences between the predicted and the observed mortality in both, men (HL = 7.7, P = 0.46) and women (HL = 11.7, P = 0.16). The discrimination of the model accounted 81% in men and 79% in women. In the validation cohort, we obtained a good calibration among men (HL = 10.1, P = 0.43) but not in women (HL = 21.4, P = 0.01). The discrimination was quite similar to the development cohort in both sexes (ROC area = 80% in men, ROC area = 78% in women).ConclusionThe comorbidity index has good calibration and discrimination and was successfully validated in a different population-based cohort among men but not among women.