Abstract 14242: Temporal Trends and Clinical Course of Deep Vein Thrombosis in Evacuees Post2016 Kumamoto Earthquakes

IntroductionKumamoto prefecture in Japan was struck by a series of earthquakes, including a maximum magnitude (Mw) 7.3 on April 16, 2016. After the earthquakes, more than 180,000 people evacuated to shelters or private vehicles. Although high prevalence rates of deep vein thrombosis (DVT) have been reported in earthquake evacuees, clinical courses of DVT cases and adequate treatment regimens have yet to be revealed.MethodsDuring the series of earthquakes, we performed mobile DVT screening in evacuation shelters utilizing ultrasonography (US) and investigated the prevalence and risk factors of DVT in acute phase (between April 19 and May 31, 2016), furthermore, the temporal trends of DVT during 30 months were examined (from June 2016 to November 2018) in the initial examinees. Concomitantly, a serial follow-up US surveys for DVT positives detected in the acute phase were performed at 2 to 30 months after the first examination. A telephone survey of DVT-positives was also performed.ResultsDuring the acute phase, 2,315 examinees received mobile US screening, DVT was detected in 220 (9.5%) examinees. On multivariable logistic regression analysis, high age (≥70 years old), use of sleep medication, lower leg edema, and lower leg varices were significant predictors for DVT. Of 22 evacuees with D-dimer >2.0 μg/mL, 3 patients required urgent hospitalization. A telephone survey at 12 months revealed no deaths among DVT positives in acute phase. Although continued screening for 1,322 initial examinees in the chronic phase revealed no apparent reduction in the positive rate of DVT over time, limited in subjects younger than 75 years, positive rate gradually decline during the 30 months (from 7.0% in acute phase to 1.7% in 2018). Serial US follow-up for DVT positives revealed that 56.7% became negative within the follow-up period,49% of negative conversion cases disappeared within 2 months, and 87% within 6 months.Among the subjects with negative conversion of DVT, only 18% of those received anticoagulants for the DVT.ConclusionsThe chronically decreasing DVT positive rates in the nonelderly subjects evokes the presence of disaster-related DVT. The prognosis of DVT positives was good, and the majority disappeared within 6 months without medical intervention.