Development of a scoring system to assess disability in an Italian elderly population. Evaluation of a disability questionnaire

Functional disability was evaluated in a cross-section sample of 671 persons, aged > or = 60 years attending the Local Health Care Unit of Borgo San Dalmazzo, Cuneo, Italy, by the OECD (Organization for Economic Co-operation and Development) questionnaire. The unidimensionality of the item set and grading order of severity were studied by Multiple Correspondence Analysis; cumulativeness was examined by Guttman scale-analysis. The OECD set measured two dimensions of disability, physical and sensorial. By excluding the six items that caused the greatest loss of homogeneity, a reduced set of ten items was obtained that was cumulative (Reproducibility coefficient = 0.934 and Scalability coefficient = 0.778) and also produced a simpler score (0-10 points scale). Based on this score, 40% of the subjects presented no disability in running 100 metres (the most difficult task), and males were less disabled than females (p = 0.001). The level of functional disability was slightly decreased in males, and nearly uniform in females up to 70-74 years, after which a clear decrease appeared (p = 0.001). The more disabled aged state a need for a higher number of health services (injection and physical therapy, nursing hospital, nursing home, physician), but knowledge and use of these services are not clearly related to physical function. Based on our results, the choice of scaling appears irrelevant if the homogeneity of the item set is checked; if the cumulative criterion is identified, the use of a simplified cumulative score can be proposed as a sensitive measure of disability, and indirectly, the amount of personal assistance needed