Prognostic effect of comorbidities in patients with chronic myeloid leukemia treated with a tyrosine kinase inhibitor.

Comorbidities at diagnosis among patients with chronic myeloid leukemia in chronic phase (CML-CP) may affect their overall survival (OS) rate even in the tyrosine kinase inhibitor (TKI) era. However, the prognostic impact of comorbidities in patients with CML-CP treated with a second-generation TKI (2GTKI) has not been elucidated. We evaluated the effect of comorbidities on survival using the Charlson Comorbidity Index (CCI) in patients with CML-CP treated with imatinib or a 2GTKI (nilotinib and dasatinib). From April 2010 to March 2013, 506 patients with CML-CP were registered for the population-based cohort study, and 452 with a median age of 56 y were assessable. Treatment groups included 139 patients receiving imatinib, 169 receiving nilotinib, and 144 receiving dasatinib. Comorbidities were diagnosed in 99 patients. CCI scores were stratified as follows: 2, 353 patients; 3, 72 patients; and ≥4, 27 patients. Treatment response did not vary relative to CCI scores. However, across the entire cohort, the OS rate was significantly lower among patients with higher CCI scores than in those with a CCI score of 2 (94.4% in score 2, 89.0% in score 3, and 72.8% in score ≥4; P < .001). Multivariate analysis identified a CCI score of ≥4 as a strong adverse prognostic factor for OS rather than the disease-specific risk factor, older age, performance status, or selection of TKI (Wald test, P < .01). Our results demonstrated that comorbidities at diagnosis were the most important predictive factor for successful treatment, regardless of the TKI type used in CML-CP. This trial was registered at UMIN-CTR as 00003581.