Diseases that precede disability among latter-stage elderly individuals in Japan

Understanding causes of disability among elderly individuals is an important public health issue, particularly because of the increasing rate of disabled elderly individuals and the social costs in a rapidly aging society. Accordingly, we aimed to describe the diseases that precede disability and investigate the types of diseases that are related to severe disability among Japanese elderly individuals aged over 75 years. Using claim data from the latterstage elderly healthcare system and long-term care insurance system, we identified 76,265 elderly individuals over 75 years old who did not qualify as disabled on April 1, 2011. Among them, 3,715 elderly individuals who had been newly qualified as disabled between April 1, 2011 and March 31, 2012 were selected. Disease codes from the medical claim data in the 6 months prior to disability were collected. All descriptions were developed separately for six groups divided by gender and disability level (low, middle, and high). The results of the ordinal logistic analysis including sex and age revealed that men tended to have significantly higher levels of disability (β = 0.417, p < 0.001) than women. Cerebrovascular disorder (CVD) was the most common disease in almost all age and disability level groups. In low-level disability groups, cancer in men (12.8%) and arthropathy and fracture in women (11.9% and 13.5%, respectively) were as common as cerebrovascular disorder (12.2% and 9.7%, in men and women, respectively). Stroke was the most common disease for all genders and disability levels. The diseases preceding low-level disability differed by gender. This study demonstrated the need to consider arthropathy and fracture as well as CVD in order to prevent disability.