关键词: 多状态Markov模型, 老年人, 失能, 转移规律, 日常生活活动

Abstract: Background　The Fourth Sample Survey on the Living Conditions of China's Urban and Rural Older Persons showed that as of 2015，there were 40.63 million disabled and semi-disabled older persons，accounting for 18.3% of the elderly population.The disability of the elderly has become an important public health problem in China.And studying the disability transition regularity in this population is crucial to solve the problem of aging.Objective　To study the disability transition regularity in Chinese older persons using a multi-state Markov model.Methods　Data stemmed from the China Health and Retirement Longitudinal Study （CHARLS） conducted in 2011 and 2013.The disability status of the involved older people aged 60 or above was classified by the National Long Term Care Survey （NLTCS） disability criteria.Disability transition regularity was analyzed with a multi-state Markov model.Results　A total of 6 615 cases were enrolled.A two-year follow-up showed that，compared with baseline，3 740 （56.54%） of the participants were found to have little changed functional state，837 （12.65%） showed improvement in functional state，1 704 （25.76%） demonstrated declined functional state，and 334 （5.05%） died.The functional state had a possibility to be improved regardless of the baseline status.Mild disability had the highest probability of improvement （0.414 0）．Those who were disabled at baseline had higher possibility of transition in functional state than those who were nondisabled at baseline.However，the possibility of improvement in functional state was negatively correlated with the level of disability at baseline，namely，it decreased successively in participants with baseline assessed mild，moderate and severe disability.The possibility of improvement in functional states was higher than that of deterioration in those with impaired health，mild or moderate disability，but in those of severely disabled，a totally opposite result was observed.Those of severely disabled also showed the highest probability of death （0.355 1）．The mean sojourn time in those with healthy，impaired health，mild disability，moderate disability，and severe disability was 3.33，1.83，1.02，1.02 and 1.52 years，respectively.Conclusion　Functional states being unchanged，improved or deteriorated during a period of time are common in older persons.The transition regularity of severe disability is different from that of impaired health，mild or moderate disability.The latter three functional states have a higher likelihood of improvement，while the former，severe disability，has longer sojourn time and a lower likelihood of recovery，and the highest probability of death.

Key words: Multi-state Markov model, Aged, Disability, Transition regular, Activities of daily living