Monocyte count associated with subsequent symptomatic venous thromboembolism (VTE) in hospitalized patients with solid tumors

BackgroundSolid tumor is the strongest risk factor for VTE in Thai medical in-patients. This study aimed to identify the markers predicting symptomatic VTE in this group.MethodsSolid tumor patients admitted to the medical wards from June 2007 to December 2009 were monitored for VTE symptoms, excluding patients with VTE on admission. Anticoagulant prophylaxis was not given. Cases were all symptomatic VTE within 6 weeks after discharge. The controls were active solid tumor in-patients admitted in 2009 and did not develop VTE. The cases and controls were compared for the risk factors of VTE and complete blood count (CBC) on admission.ResultsThere were 28 radiology-confirmed VTE cases during the 2.5-year study period. There were 280 solid tumor patients without VTE as the controls. There was no difference in age (58.4 vs. 61.6 years), sex (53.6% vs. 64.3% male), presence of leg paralysis, acute infection and obesity between cases and controls, respectively. The cases showed higher absolute monocyte counts compared with the controls (0.76 vs. 0.56 × 109/L, p 0.013), but there were no differences in other CBC parameters. In a multivariate analysis, cancer of unknown primary (Odds ratio [OR] 13.7, 95% confidence interval [CI] 2.74-68.7, p 0.001), biliary cancer (OR 6.6, 95% CI 1.80-24.3, p 0.004) and a monocyte count over 0.5 × 109/L (OR 5.0, 95% CI 1.62-15.5, p 0.005) significantly associated with VTE.ConclusionMetastatic diseases with obscured primary sites, biliary carcinomas and higher monocyte counts on admission are related to subsequent VTE in hospitalized cancer patients.