National trends in the proportion of in-hospital deaths by cause of death among older adults with long-term care: a nationwide observational study in Japan from 2007 to 2017

BACKGROUND: Japan has promoted end-of-life care at home and in long-term care facilities, and the total proportion of in-hospital deaths has decreased recently. However, the difference in trends of in-hospital deaths by the cause of death remains unclear. We investigated the variation in trends of in-hospital deaths among older adults with long-term care from 2007 to 2017, by cause of death and place of care. METHODS: Using the national long-term care insurance registry, long-term care claims data, and national death records, we identified people aged 65 years or older who died between 2007 and 2017 and used long-term care services in the month before death. Using a joinpoint regression model, we evaluated time trends of the proportion of in-hospital deaths by cause of death (cancer, heart diseases, cerebrovascular diseases, pneumonia, and senility) and place of care (home, long-term care health facility, or long-term care welfare facility). RESULTS: Of the 3,261,839 participants, the mean age was 87.0 ± 8.0 years, and 59.2% were female. Overall, the proportion of in-hospital deaths decreased from 66.2% in 2007 to 55.3% in 2017. By cause of death, the proportion of in-hospital deaths remained the highest for pneumonia (81.6% in 2007 and 77.2% in 2017) and lowest for senility (25.5% in 2007 and 20.0% in 2017) in all types of places of care. The joinpoint regression analysis showed the steepest decline among those who died of senility, especially among long-term care health facility residents. CONCLUSIONS: The findings of this nationwide study suggest that there was a decreasing trend of in-hospital deaths among older adults, although the speed of decline and absolute values varied widely depending on the cause of death and place of care. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12877-021-02700-1.