Observations in the diseased cohort and in matched controls from the non-diseased cohort are used to determine excess costs and QoL changes attributable to CAP.Based on an estimated 2,000 CAPiTA participants being hospitalized with CAP and an assumed CHO-CAP participation rate of 30 % of all CAPiTA participants ( 25,000 ) , 600 CAP episodes are expected among CHO-CAP participants ( the `` diseased '' cohort ) .