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

In 816 patients with 2016 WHO-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 sub-grouped 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 (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 (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). However, CCI≥2 was associated with reduced survival (HR 1.81, p=0.03). 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. This article is protected by copyright. All rights reserved.