[The Relative Complexity Index beta: value of each parameter]

The French health policy PMSI project (Program for a Medical Information System) is mainly aimed at development of cost analysis based on diagnosis related groups. An indicator of the relative costs of anaesthetics, the relative complexity index (ICR beta), was defined as the result of a computation of different indexes of surgical and anaesthetic procedures such as duration, patients ASA status, degree of emergency, stay in the recovery room. The aims of this study were 1) to analyze relative part of each index in ICR beta value and in ICR beta variance and 2) to assess the value of ICR beta as a cost or a complexity index. The study included 14,435 anaesthetics analyzed with the Dunn and Clarks multiple linear regression. Mean ICR beta was 267.28. The duration of the procedure accounted for 46% of the ICR beta value and surgery for 25%. The anaesthesia and the recovery accounted for 15% of the ICR beta value, but only for 0.0341 and 0.0347 respectively of the ICR beta variance. The product of the surgical procedure index by the ASA status index accounted for 0.259 of the ICR beta variance and the duration index for 0.650. The comparison of homogeneous groups with regard to the surgical procedure shows that intravenous anaesthesia accounts for 12.4% of the ICR beta value, inhalational anaesthesia for 13.84%, but exceeds 15% for regional anaesthesia (44.5% for caudal anaesthesia). For appendectomies (n = 114) duration index is still an important parameter in ICR beta variance (delta R2 = 0.354) but equivalent to the emergency index (delta R2 = 0.363).(ABSTRACT TRUNCATED AT 250 WORDS)