Sustained Increase in the Incidence of Acute Decompensated Heart Failure After the 2011 Japan Earthquake and Tsunami

This study investigated the long-term impact of the 2011 Japan earthquake and tsunami on the incidence of acute decompensated heart failure (HF) in the disaster area. This was a population-based study using comprehensive registration for all hospitals within the study area. The standardized incidence ratio (SIR) and 95% confidence interval (CI) for new onset of HF during the disaster year (2011) and postdisaster years (2012 to 2014) were determined. When SIR were compared between the low- and high-impact areas, as defined by the extent of tsunami inundation in residential areas, SIR showed a significant increase in high-impact areas in 2011 (1.67, 95% CI 1.45 to 1.88) and tended to return to baseline in 2012, the first postdisaster year (1.25, 95% CI 1.06 to 1.43). The rate again increased in 2013 (1.38, 95% CI 1.18 to 1.57) and 2014 (1.55, 95% CI 1.35 to 1.75). In low-impact areas, no such increase was apparent during either the disaster year or the postdisaster years. Mean postdisaster period SIR for municipalities significantly correlated with the percentage of tsunami flooding in residential areas (r = 0.52, p <0.05) and with the percentage of refugees within the population (r = 0.74, p <0.01). There was no significant relation between maximum seismic intensity and mean SIR in these municipalities. In conclusion, these results suggest that the catastrophic tsunami but not the earthquake per se resulted in a prolonged increase in the incidence of HF among the general population living in tsunami-stricken areas.