Long-term prognostic impact of the Great East Japan Earthquake in patients with cardiovascular disease - Report from the CHART-2 Study.

Background: We and others have previously reported that the Great East Japan Earthquake (GEJE) caused a significant but transient increase in cardiovascular diseases and deaths in the disaster area. However, it remains to be examined whether the GEJE had a long-term prognostic influence in large-scale cohort studies. This point is important when analyzing the data before and after the GEJE in the cohort studies in the disaster area.

Methods: We examined 8676 patients registered in our Chronic Heart Failure Analysis and Registry in the Tohoku District-2 (CHART-2) Study (N=10,219) between 2006 and 2010 and were alive after March 10, 2011.

Results: There were 48 GEJE-related deaths, causing a sharp and transient increase in all-cause death within a month after the GEJE. However, after excluding the GEJE-related deaths, the cubic polynomial spline smoothing showed no significant increase in all-cause death, heart failure admission, non-fetal acute myocardial infarction, or non-fetal stroke during the median 3-year follow-up after the GEJE. The extrapolation curves beyond the GEJE, which were obtained by the parametric survival models based on the survival data censored on the GEJE, were not significantly different from the Kaplan-Meier curves estimating the survival functions of deaths and cardiac events during the total follow-up period without considering the impacts of the GEJE. Furthermore, the multivariate Cox proportional hazard model applied to the matched cohort of the baseline data and the data after the GEJE showed no significant differences in the impacts of prognostic factors on all-cause mortality before and after the GEJE.

Conclusions: These results indicate that the GEJE had no significant long-term prognostic impact after the earthquake in cardiovascular patients in the disaster area.