Hux J E, Naylor C D
Institute for Clinical Evaluative Sciences in Ontario, University of Toronto, Ontario, Canada.
Lancet. 1996 Nov 2;348(9036):1202-7. doi: 10.1016/s0140-6736(96)04091-3.
Population-based rates of surgery vary within and between health-care systems, causing concern that case selection is less appropriate in high-rate areas. This inverse relationship has not been shown with appropriateness criteria generated by expert panels. We applied a trials-based measure of the potential survival benefit of coronary artery bypass graft surgery (CABG) to patients in a provincial registry, to determine the relationship between survival gains and rates of CABG.
We did a population-based retrospective review of linked registry and administrative datasets. 5058 patients in the linked datasets underwent isolated CABG in Ontario between April 1, 1992, and March 31, 1993. Potential survival benefit of surgery was scored with an algorithm derived from a published overview of trials comparing CABG to medical treatment, analysed by county and by referral regions.
Overall, case selection was appropriate whether assessed clinically (96.3% had either severe disease as judged on the coronary arteries affected or moderate to severe angina) or on the basis of survival benefit scores (94.0% predicted to obtain moderate or high benefit). There was significant variation in benefit scores across referral regions (p < 0.001). Benefit scores correlated inversely with county surgical rate (r = -0.49, p < 0.005) and the proportion of low-benefit cases increased with rates (r = 0.50, p < 0.005). Referral regions served by high-rate surgical centres had lower mean benefit scores.
Most patients undergoing CABG in Ontario are in the high-survival benefit category. Surgery is defensible for patients with low survival benefit on the grounds of symptom relief, but the proportion of cases with low benefit rises with higher local rates of surgery. The inverse relationship between surgery rates and appropriateness of case selection may be better understood as diminishing marginal returns for specific outcomes with rising local use of procedures.
基于人群的手术率在不同医疗系统内部和之间存在差异，这引发了人们对高手术率地区病例选择是否更不合理的担忧。但这种反比关系在专家小组制定的适宜性标准中并未得到体现。我们将一种基于试验的冠状动脉搭桥手术（CABG）潜在生存获益的衡量方法应用于省级登记处的患者，以确定生存获益与CABG手术率之间的关系。
我们对关联的登记处和行政数据集进行了基于人群的回顾性研究。在1992年4月1日至1993年3月31日期间，关联数据集中的5058名患者在安大略省接受了单纯CABG手术。手术的潜在生存获益通过一种算法进行评分，该算法源自一项已发表的比较CABG与药物治疗的试验综述，并按县和转诊地区进行分析。
总体而言，无论从临床角度评估（96.3%的患者患有严重疾病，根据受影响的冠状动脉判断或患有中度至重度心绞痛）还是基于生存获益评分（94.0%预计获得中度或高度获益），病例选择都是合适的。各转诊地区的获益评分存在显著差异（p < 0.001）。获益评分与县手术率呈负相关（r = -0.49，p < 0.005），低获益病例的比例随手术率上升而增加（r = 0.50，p < 0.005）。由高手术率中心服务的转诊地区平均获益评分较低。
安大略省大多数接受CABG手术的患者属于高生存获益类别。对于生存获益低的患者，基于症状缓解的理由，手术是合理的，但低获益病例的比例会随着当地手术率的升高而增加。手术率与病例选择适宜性之间的反比关系可能更好地理解为随着当地手术操作使用的增加，特定结局的边际收益递减。
