Heart failure epidemiology and novel treatments in Japan: facts and numbers

Japan has the highest proportion of older people in the world, 25.9% of the population were aged 65 or above in 2014. Although there have been no population‐based studies that precisely examined the prevalence of heart failure in Japan, one report estimated the number of Japanese outpatients with left ventricular dysfunction was 979, 000 (0.8% of total population), which was projected to increase gradually as the population ages, reaching 1.3 million by 2030. Ischemic etiology was less frequently observed in Japan (31–47%) than in western population (54–57%). The prevalence of HF with preserved ejection fraction was similar between Japan (34–68%) and western countries (34–51%). Non‐cardiac co‐morbidities such as chronic obstructive pulmonary diseases and anemia were observed in 6–9% in Japan and 19–31% in western countries, and 35–58% in Japan and 37–56% in western countries, respectively. The definition of chronic kidney disease widely differed among studies. A relatively good survival prognosis in Japanese patients has been discussed. One‐year mortality after discharge from initial hospitalization was 9–12%, which seems to be better than the western cohort. Although length of stay was remarkably longer in Japan (15–21 days) than western countries (4–9 days), it will have to be shortened, as Japan is now being faced with an upcoming HF pandemic. Some treatments in Japan are not approved outside Japan. Such treatments include carperitide infusion (used in 58% of hospitalized HF), nicorandil infusion (9.6%), and oral pimobendan (5%). More recently, landiolol and tolvaptan have been approved. Although these drugs might have a potential to be an effective therapeutic option, lack of corroborating evidence in many of such treatments would emphasize the need for larger clinical trials.