The relationship between monoclonal gammopathy of undetermined significance and venous thromboembolic disease

IntroductionMonoclonal gammopathy of undetermined significance (MGUS) has been proposed to be a risk factor for venous thromboembolic disease (VTE). However, no series published to date has been population-based or included a control group with similar comorbidities to people with MGUS.Patients/MethodsWe reviewed the records of all the male veterans in a single VA healthcare system with MGUS between January 1, 1996 and December 31, 2005. We compared the rate of VTE in 166 patients with MGUS with the rate of VTE in an age-matched control group of 465 patients who had tested negative for monoclonal gammopathy by serum protein electrophoresis (SPEP).ResultsThe VTE rate in the MGUS group was 2.2 per 100 person-years, which was not significantly different from the rate in the control group, 1.4 per 100 person-years (HR 1.38, CI 0.63-3.01, p = 0.42). Most VTE events occurred within 4 months of the diagnosis of MGUS. In univariate analysis, albumin level (HR 0.21, CI 0.1-0.41, p < 0.001), abnormal leukocyte count (HR 2.53, CI 1.09-5.86, p = 0.03), and history of prior VTE (HR 4.41, CI 1.69-11.54, p = 0.003) were associated with increased risk of VTE. On multivariate analysis, albumin level and history of prior VTE remained significant, but presence of MGUS was still not significantly associated with VTE risk.ConclusionOur results suggest that the increased rate of VTE in people with MGUS may be primarily due to other underlying conditions that led to testing for a monoclonal gammopathy rather than to the monoclonal gammopathy itself.