Objective: To ascertain predictors for the onset of different levels of certification of long-term care insurance among older adults living independently in a community.
Methods: Out of all residents aged 65 years and over living in Yoita town, Niigata prefecture, Japan (n = 1,673), 1,544 persons participated in the baseline interview survey in 2000 (response rate, 92.3%). Among these participants, 1,229 persons (79.6% of responders) were ranked as level 1, based on the hierarchical mobility level classification. They were followed up for the subsequent 3 years and 4 months to see whether they continued without certification of long-term care insurance or suffered onset of a "mild level", certified as levels "needing support" and 1 for long-term care insurance, or a "severe level" as 2-5. The Cox proportional hazards model with a stepwise method was used to identify the most parsimonious combination of predictors for each type of long-term care insurance certification.
Results: Of those who were followed up, 1,151 persons showed no disability in basic activities of daily living (ADL) at baseline nor died before application for long-term care during the follow-up and thus served for analysis. 1,055 persons (91.7%) remained as "no event", but 49 (4.3%) and 47 persons (4.1%) had onset of the "mild level" and the "severe level" during the follow-up, respectively. The final model for prediction of the "mild level" in both genders included advanced age and poor walking ability (hazard ratio (HR) for either unable or with difficulty: 7.22[95% CI, 1.56-33.52] in males and both unable and with difficulty: 3.28[95% CI, 1.28-8.42] in females). The final model for prediction of the "severe level" in both genders included advanced age and poor instrumental ADL (HR for < or = 4 marks: 3.74[95% CI, 1.59-8.76] in males and 3.90[95% CI, 1.32-11.54] in females). Severe cognitive decline was a predictor only for the "severe level" in males. A history of hospitalization during past 1 year and poor chewing ability were predictive only for the "mild level" in females.
Conclusions: Among older adults living independently in a community, most predictors for subsequent onset of mild level-certification of long-term care insurance, except for advanced age, may be controlled by preventive strategies. Evaluating effectiveness of programs for this purpose warrants further study.