Residents of the intervention wards had significantly less hospital days ( 1.4 days/person/year , 95 % CI 1.2-1 .6 ) than in the control wards ( 2.3 days/person/year ; 95 % CI 2.1-2 .7 ) ( relative risk 0.60 , 95 % CI 0.49-0 .75 , P < .001 , adjusted for age , sex , and comorbidities ) .