Association between the disability prevention program "Secondary Preventive Services" and disability incidence among the elderly population: A nationwide longitudinal comparison of Japanese municipalities

Aim: The aim of the present ecological study was to evaluate the relationship between the rate of participation in Secondary Preventive Services (SPS) and the incidence of disability in Japanese municipalities. Methods: We used the national statistics data for Long-term Care Insurance (LTCI), because all Japanese people aged ≥65 years are eligible for LTCI services depending on their functional status assessed by a national uniform standard in all municipalities. The disability incidence rate for the 2-year period in 2009-2010 was compared among five different levels of SPS participation in 2006-2008. The primary outcome was the sum total disability incidence rate in LTCI from 2009 to 2010. The outcome was divided according to disability level into three patterns: "all levels (Support Level 1 - Care Level 5)", "mild disability (Care Level ≤1)" and "moderate to severe disability (Care Level ≥2)". Results: There was a significant inverse association between the SPS participation rate and disability incidence rate. Among 1541 municipalities, those in the highest SPS participation rate quintile (≥9.79 per 1000 elderly population) had a lower disability incidence rate for all levels than those in the lowest quintile (<1.86 per 1000 elderly population; absolute rate difference 0.6%; age-adjusted incident rate ratio 0.94; 95% CI 0.89-0.99). This inverse association was observed for mild disability and not for moderate to severe disability. Conclusions: Municipalities with a higher SPS participation rate have a lower incidence rate of mild disability. SPS could be an effective health policy for containing mild disability incidence among the elderly.