Multimorbidity and Multiple Disabilities: Present Status and the Roles of Rehabilitation.

The world is aging, and an increasing number of countries are becoming aged or super-aged societies. Japan has already become the world's first super-aged society, with an aging rate of 29.1% of the entire population of the country. As of 15 September 2021, there were approximately 36.40 million people aged 65 years and over. The advent of the super-aged society has increased the possibility of multimorbidity and multiple disabilities (MMDs) in the elderly population. According to a survey by the Ministry of Health, Labour and Welfare, the percentage of people with multiple disabilities of all people with physical disabilities has fluctuated between 4.0 and 7.0%, but rapidly increased to 8.9% in 2006 and 17.7% in 2016. This review aimed to establish the present status of MMDs and the rehabilitation for MMDs. In rehabilitation settings, patients with MMDs are more common than patients with a single disease or disability; however, evidence on MMD rehabilitation is insufficient. Inexperienced and unconfident medical professionals are overly cautious in providing rehabilitation; therefore, adequate rehabilitation is not provided. Furthermore, to respond to the rehabilitation needs of patients with MMDs, human resources need to be cultivated, and a scientific basis needs to be built. It is expected that MMD guidelines will soon be developed based on various case studies and surveys. In MMD rehabilitation, it is important to provide "