Development of a risk assessment scale predicting incident functional disability among older people: Japan Gerontological Evaluation Study

AIM: The aim of the present study was to develop a risk assessment scale for predicting incident functional disability among older adults. METHODS: We used prospective cohort data from the Japan Gerontological Evaluation Study, a nationwide survey of 90 889 functionally independent older people collected from 23 municipalities. The incidence of functional disability was determined from long‐term care information obtained from municipal insurance databases. We constructed a Cox proportional hazards model with forward stepwise selection that used sex, age, and 12 of the essential items of the Public Survey of Long‐Term Care Prevention and Needs in Spheres of Daily Life (the Needs Survey). We assigned a score based on the obtained non‐standardized regression coefficients for each item and summed the scores to establish the risk assessment scale. The predictive validity was examined. RESULTS: The cumulative incidence of functional disability during the 3‐year follow‐up period was 9.7%. A risk assessment scale of 0–48 that used sex, age and the Needs Survey's 10 essential items was established. The area under the receiver operating characteristic curve was 0.804, and the sensitivity and specificity were both 0.733 (cut‐off 16/17). There was no significant intermunicipality difference in the associations between the total scores calculated by using the scale and the risk of new incidence (P = 0.135). CONCLUSIONS: We developed a risk assessment scale predicting incident functional disability composed of 10 essential items of the Needs Survey, sex and age. The scale had superior predictive validity, regardless of the level of urbanness. Geriatr Gerontol Int 2018; 18: 1433–1438.