[Health check-up results, death, and occurrence of the need for nursing care among Japanese older adults: Analysis using the Kokuho Database system].

Objectives　The study aimed to clarify the association among health check-up results, death, and occurrence of the need for nursing care among Japanese older adults.Methods　The participants were 24,909 males and 28,742 females. A medical system for late-stage older adults in the Tochigi Prefecture (Japan) insured, not qualified for long-term care insurance certification, and participated in health check-ups from April 2020 to March 2021. We recorded the occurrence of death and loss of independence from the date of health check-ups through the end of August 2021. Furthermore, we divided the participants into two groups based on the judgment value of medical consultation recommendations for the specified medical check-ups. In addition, we calculated 1-year survival and independence rates using the Kaplan-Meier method and estimated hazard ratios (HRs) of death and loss of independence using the Cox's proportional hazard model.Results　During the follow-up, 424 cases of deaths (281 males and 143 females) and 1,011 cases of loss of independence (529 males and 482 females) were identified. In addition, 1-year survival and independence rates for low serum albumin were 0.920-0.958, with the lowest in both the sexes. The Cox's proportional hazards model after adjusting for age, body mass index, and responses to the late-stage older adult questionnaire revealed that HRs of death (3.05 [2.00-4.64]) and loss of independence (2.58 [1.87-3.56]) for low hemoglobin were the highest in males, and those of death (5.87 [2.45-14.07]) and loss of independence (3.00 [1.70-5.29]) for low serum albumin were particularly high in females. In a previous study analyzing the loss of independence among older adults who participated in health check-ups, HRs of death for low serum albumin and hemoglobin were 2.7 [1.2-6.0] and 1.8 [1.1-2.9], respectively, and the current study results showed a higher tendency than that in the previous study. In addition, previous studies showed an association between low serum albumin and stroke and low hemoglobin and death. However, in the current study, HRs for low serum albumin and hemoglobin could be particularly high because the Tochigi Prefecture has a high age-adjusted mortality rate for cerebrovascular and cardiac diseases, in addition to low nutrition among individuals with risk factors for these diseases.Conclusion　This study found that low nutrition among older adults in the Tochigi Prefecture was highly associated with the occurrence of death and the need for nursing care. In addition, the trends in mortality and the risk of loss of independence among older adults differed by region.