Impact of comorbidities and body mass index on the outcome of polycythemia vera patients.

Abstract

In 816 patients with 2016 World Health Organization-defined polycythemia vera (PV) enrolled in a multicenter retrospective study, we investigated the predictive value of Charlson comorbidity index (CCI) and body mass index (BMI) on thrombosis, progression to post-PV myelofibrosis (PPV-MF) and survival. Patients were subgrouped according to CCI=0 (58.1%, no comorbidities) or CCI≥1 (41.9%) and according to normal/underweight (BMI<25, 54.5%) or overweight/obesity (BMI≥25, 45.5%) at PV diagnosis. BMI was available for 529 patients. Patients with CCI≥1 were older and more frequently presented cardiovascular risk factors compared to patients with CCI=0 (p<0.001), while overweight/obese patients were more frequently males (p<0.001). Cumulative incidence of thromboses with death as competing risk was 13.3% at 10 years. Multivariable analysis with death as competing risk showed that previous thromboses (subdistribution hazard ratio [SHR]:2.1, p=0.01) and hypertension (SHR: 1.77, p=0.04) were significantly associated with a higher thrombotic risk, while BMI≥25 lost statistical significance (SHR: 1.69, p=0.05) and CCI≥1 was excluded after evaluation of goodness of fit. After a median follow-up of 6.1 years, progression to PPV-MF occurred in 44 patients, and 75 patients died. BMI≥25 was associated with a lower probability of progression to PPV-MF (SHR: 0.38, CI95%: 0.15-0.94, p=0.04) and better survival (hazard ratio [HR]: 0.42, CI95%: 0.18-0.97, p=0.04). CCI≥1 did not affect progression to PPV-MF (p=0.44) or survival (p=0.71). The evaluation of CCI and BMI may improve the prognostic definition of PV. In patients with hypertension an accurate evaluation of thrombotic risk is warranted.