[Chronic lymphocytic leukemia].

© Fe rra ta St ort i F ou nd ati on this on-site documentation, causes of death were grouped into the following categories: therapy-related, CLL-related, CLL-unrelated, or unknown. Both studies were approved by the Institutional Review Board and Ethics Committee of the University of Munich and performed in accordance with the Declaration of Helsinki. Comorbidity assessment For both trials, comorbid conditions present at baseline had to be assessed and documented in the patient’s case report form by the treating physician. Further quantification of the comorbidity burden by use of specific comorbidity scores was not part of the study protocols. Thus, all comorbid conditions reported within the case report form were captured only in a qualitative manner. Health problems resulting from the CLL itself and CLL as the primary disease were not recorded as comorbidity. To assess the comorbidity burden for each patient individually in the absence of quantitative data derived from scores, the number of comorbidities was calculated as the sum of all conditions abstracted from the patient’s case report form according to the rules described above. Since information on the severity of comorbid conditions was mostly unobtainable, a retrospective scoring of comorbidity by use of a validated comorbidity score was not reliably possible (although an attempt was made to calculate the Charlson comorbidity index from the available data). For a general description of the spectrum of comorbidities in the study population, each of the concomitant diseases was assigned to disease categories abstracted from the Cumulative Illness Rating Scale. Statistical analysis The statistical analysis was performed with SPSS 17 software (SPSS Inc., USA) and based on data collected by December 17 2009 for the CLL4 trial and August 1 2007 for the CLL5 trial (parts of this analysis were also performed earlier on a 2005 dataset and previously presented in abstract format). Estimates of overall and progression-free survival were calculated using the Kaplan-Meier method. The log-rank test was used to compare survival times between groups. A Cox regression model was applied for univariate and multivariate analyses to estimate hazard ratios. Parameters others than survival were compared using the c test and the Fisher exact test. Further details on the methods of this study are available in the Online Supplementary Appendix.