title: The use of patient mix-adjusted control charts to compare in-hospital costs of care.
abstract: We introduce a technique for patient mix-adjusting x charts and compared differences between unadjusted and patient mix-adjusted results. Our data came from coronary artery bypass graft (CABG) surgery patients at Baptist Medical Center, Oklahoma City, Oklahoma. We first developed an unadjusted x control chart to compare monthly changes in CABG surgery costs and then used a published model to patient mix-adjust our x control chart information. Before adjustment, the average log costs for three of ten months were outside the 90% control limit lines, and there was a trend toward increasing costs. After adjustment, two months had average costs outside the 90% lower control limit lines, and the trend toward increasing costs had been explained by differences in patient acuity.
authors.affiliation: Duke University Medical Center, Durham, NC 27710, USA. eric.eisenstein@duke.edu
authors.forename: E L
authors.initials: EL
authors.lastname: Eisenstein
authors.forename: C F
authors.initials: CF
authors.lastname: Bethea
mesh_terms: D000066:Accounting / Q000379:methods; D000368:Aged; D001026:Coronary Artery Bypass / Q000191:economics*; D003361:Cost Allocation / Q000379:methods; D003953:Diagnosis-Related Groups / Q000145:classification / Q000191:economics*; D006302:Health Services Research / Q000379:methods; D017721:Hospital Costs / Q000706:statistics & numerical data*; D006764:Hospitals, Community / Q000191:economics*; D006801:Humans; D007902:Length of Stay / Q000706:statistics & numerical data; D008875:Middle Aged; D017059:Models, Econometric; D009825:Oklahoma