Predictors of Hypertension in Survivors of the Great East Japan Earthquake, 2011: A Cross-sectional Study

Abstract

Introduction: Many survivors of a major disaster die shortly after the event. Hypertension (HT) is one of the most important risk factors for these disaster-related diseases. An urgent need exists to establish methods to detect disaster survivors with HT and start medication immediately, as those with no injuries or symptoms may not be examined and medical teams cannot measure all survivors' blood pressure (BP) because they often do not have sufficient time.

Objective: The goals of this report were: (1) to evaluate the importance of taking antihypertensive drugs continuously for patients with HT during the sub-acute phase after a major earthquake, when patients cannot attend a clinic because of destruction of the local infrastructure; and (2) to establish simple and reliable predictors to detect evacuees with HT, who require clinical examination and treatment at evacuation shelters or in their homes after a major earthquake.

Methods: Medical rounds were performed at evacuation shelters in Iwate Prefecture after the Great East Japan Earthquake. Forty evacuees were enrolled in a cross-sectional study. The effect of taking antihypertensive drugs continuously was evaluated and predictors of HT in evacuees were identified using multiple logistic regression analysis.

Results: Twenty-eight evacuees were hypertensive (70%), nine of whom were asymptomatic (32%). Most evacuees who had discontinued antihypertensive medication (92%; 11/12) had very high BP, while those who had continued antihypertensive medication (80%; 8/10) were mildly hypertensive. The systolic BP of those who had discontinued antihypertensive drugs was significantly higher than that of those who had continued hypertensive drugs in the whole cohort (n=40), and also in evacuees diagnosed as having HT at evacuation shelters (n=28; P55 years (aOR, 1.10; 95% CI, 1.01-1.21) predicted HT with a sensitivity of 0.96 and specificity of 0.80.

Conclusions: The results of this study suggest that continuity of antihypertensive medication prevents serious HT at evacuation shelters in the first 10 days after a major earthquake. Onsite medical rounds focusing on simple predictors in an early stage after disasters may be an effective means of detecting and treating hypertensive disaster victims before they succumb to a fatal disease.

Keywords: ARB angiotensin II receptor blocker; BP blood pressure; CA calcium antagonist; DBP diastolic blood pressure; DMATs Disaster Medical Assistance Teams; Great East Japan Earthquake; HT hypertension; ROC receiver operator characteristic; SBP systolic blood pressure; blood pressure; disaster hypertension; disaster-related death; psychological stress.