Carey Mark S, Victory Rahi, Stitt Larry, Tsang Nicole
Department of Obstetrics and Gynecology, University of Western Ontario, London ON; London Health Sciences Centre, London ON.
J Obstet Gynaecol Can. 2006 Feb;28(2):149-55. doi: 10.1016/s1701-2163(16)32057-6.
To compare the association between the Case Mix Group (CMG) code and length of stay (LOS) with the association between the type of procedure and LOS in patients admitted for gynaecology surgery.
We examined the records of women admitted for surgery in CMG 579 (major uterine/adnexal procedure, no malignancy) or 577 (major surgery ovary/adnexa with malignancy) between April 1997 and March 1999. Factors thought to influence LOS included age, weight, American Society of Anesthesiologists (ASA) score, physician, day of the week on which surgery was performed, and procedure type. Procedures were divided into six categories, four for CMG 579 and two for CMG 577. Data were abstracted from the hospital information costing system (T2 system) and by retrospective chart review. Multivariable analysis was performed using linear regression with backwards elimination.
There were 606 patients in CMG 579 and 101 patients in CMG 577, and the corresponding median LOS was four days (range 1-19) for CMG 579 and nine days (range 3-30) for CMG 577. Combined analysis of both CMGs 577 and 579 revealed the following factors as highly significant determinants of LOS: procedure, age, physician, and ASA score. Although confounded by procedure type, the CMG did not significantly account for differences in LOS in the model if procedure was considered. Pairwise comparisons of procedure categories were all found to be statistically significant, even when controlled for other important variables.
The type of procedure better accounts for differences in LOS by describing six statistically distinct procedure groups rather than the traditional two CMGs. It is reasonable therefore to consider changing the current CMG codes for gynaecology to a classification based on the type of procedure.
比较病例组合分类（CMG）编码与住院时间（LOS）之间的关联，以及妇科手术患者手术类型与住院时间之间的关联。
我们查阅了1997年4月至1999年3月期间因CMG 579（子宫/附件大手术，无恶性肿瘤）或577（卵巢/附件大手术伴恶性肿瘤）而入院接受手术的女性患者记录。认为可能影响住院时间的因素包括年龄、体重、美国麻醉医师协会（ASA）评分、医生、手术进行的星期几以及手术类型。手术分为六类，CMG 579有四类，CMG 577有两类。数据从医院信息成本核算系统（T2系统）中提取，并通过回顾性病历审查获得。使用线性回归和向后剔除进行多变量分析。
CMG 579组有606例患者，CMG 577组有101例患者，CMG 579组相应的中位住院时间为4天（范围1 - 19天），CMG 577组为9天（范围3 - 30天）。对CMG 577和579两组的综合分析显示，以下因素是住院时间的高度显著决定因素：手术、年龄、医生和ASA评分。尽管受手术类型的影响，但如果考虑手术因素，CMG在模型中对住院时间差异的解释并不显著。即使在控制了其他重要变量的情况下，手术类别之间的两两比较也均具有统计学意义。
通过描述六个在统计学上不同的手术组，手术类型比传统的两个CMG能更好地解释住院时间的差异。因此，考虑将当前妇科的CMG编码改为基于手术类型的分类是合理的。
