Cleary R, Beard R W, Chapple J, Coles J, Griffin M, Joffe M, Welch A
CASPE Research, London, UK.
Br J Obstet Gynaecol. 1996 Mar;103(3):223-9. doi: 10.1111/j.1471-0528.1996.tb09710.x.
To assess the suitability of the standard primipara (a subset of the obstetric population that has relatively low risk or intervention and of adverse outcome) for making inter-unit comparisons of indicators of the process and outcome of maternity care.
Inter-unit comparison of 10 indicators of obstetric intervention and adverse outcome derived from routinely collected computerised data held on the St Mary's Maternity Information System.
Fifteen maternity units in the former North West Thames Region.
15,463 primiparae who were delivered in 1992.
Proportion of primiparae within the standard definition; degree to which standard primiparae are associated with lower rates of intervention and adverse outcome, as compared to other primiparae.
Within the database, 42.6% of all primiparae were found to be standard, with rates varying between units from 25.9% to 57.7%. As expected, the standard primiparous woman is at less risk of intervention or adverse outcome than other primiparae. All but one component variable of the standard definition is a significant risk factor for at least four of the 10 indicators. Statistically significant differences in indicator rates are seen between standard and nonstandard primiparae within units. Within the standard group, significant differences in rates of intervention and adverse outcome are seen between units. Units with relatively high levels of intervention within the higher risk nonstandard group also have relatively high levels of intervention within the standard group.
Use of the standard primipara, rather than the whole obstetric population, as the basis for inter-unit comparisons of maternity care will control for the substantial difference in case mix seen in different units, thereby increasing the validity of those comparisons. The technique has the additional benefit of clarifying the relationship between everyday clinical decision making and a unit's performance in comparative indicator reports. The approach must be combined with a separate study of the other groups in the case mix, such as multiparae and high risk primiparae. Additional nonoverlapping groups, homogeneous in terms of risk factors, should be defined and used to extend the basis on which comparisons may be made.
评估标准初产妇（产科人群中的一个子集，其风险或干预以及不良结局相对较低）用于进行产科护理过程和结局指标的单位间比较的适用性。
对从圣玛丽产科信息系统中常规收集的计算机化数据得出的10项产科干预和不良结局指标进行单位间比较。
前西北泰晤士地区的15个产科单位。
1992年分娩的15463名初产妇。
符合标准定义的初产妇比例；与其他初产妇相比，标准初产妇与较低干预率和不良结局率的关联程度。
在数据库中，发现所有初产妇中有42.6%为标准初产妇，各单位的比例在25.9%至57.7%之间变化。正如预期的那样，标准初产妇比其他初产妇发生干预或不良结局的风险更低。标准定义中除一个组成变量外，所有变量都是10项指标中至少4项的显著风险因素。各单位内标准初产妇和非标准初产妇之间的指标率存在统计学显著差异。在标准组内，各单位之间的干预率和不良结局率也存在显著差异。高风险非标准组中干预水平相对较高的单位，在标准组中的干预水平也相对较高。
以标准初产妇而非整个产科人群为基础进行产科护理的单位间比较，将控制不同单位中病例组合的显著差异，从而提高这些比较的有效性。该技术还有助于在比较指标报告中阐明日常临床决策与单位绩效之间的关系。该方法必须与对病例组合中其他组别的单独研究相结合，例如经产妇和高危初产妇。应定义并使用额外的非重叠组，这些组在风险因素方面具有同质性，以扩大可进行比较的基础。
