Abstract
In this study we examined the relationship of facility characteristics and care need level deterioration of users in Japanese private residential homes, stratifying by manpower levels. Care need levels are the official measurement for long-term care certification in Japan. We used a longitudinal, multilevel logistic regression design. Data was shared by a private residential home provider. Two points of administrative data for November 2015 and November 2016 were used, with a total of 4,734 users from 112 facilities in both sets. Facilities were divided into those with (i) higher manpower, and those with (ii) lower manpower, as preliminary analyses showed the relevance of staffing levels. Higher and lower manpower levels were determined by using the median of cumulative total staff working hours per 100 users per facility at each observation point. We controlled for gender, baseline age, care-level, prefecture, grip strength, mental and physical independence and institutionalization time. Results showed that factors associated with care need level deterioration in homes with lower manpower were as follows: fewer number of users (Odds Ratio [OR]:1.05), larger capacity (OR: 1.05), newer homes (OR: 1.09), fewer number of floors (OR: 1.26), and a higher users-to-beds ratio (OR: 1.56). However, these detrimental effects were not observed in facilities with higher manpower; the associations between care need level deterioration and these factors were moderated by the level of manpower. We conclude that higher manpower while addressing other risks, may help prevent deterioration of private residential home users.