Glance L G, Osler T M
Department of Anesthesiology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA.
Crit Care Med. 2001 Nov;29(11):2090-6. doi: 10.1097/00003246-200111000-00008.
To assess the validity of using the standardized mortality ratio (SMR), based on the New York State Cardiac Surgery Reporting System (CSRS) prediction model to compare coronary artery bypass grafting (CABG) outcomes between hospitals.
The study was designed as a retrospective study based on a database containing all patients undergoing isolated CABG surgery in New York State hospitals in 1996 (n = 20,078). In the first part of this study, a computer simulation was used to assess the impact of case mix variation on the SMR. A computer-intensive algorithm was used to create 5,000 random case mixes from the patients in the CSRS database. The SMR associated with each of the 5,000 case mixes was calculated using a resampling algorithm. The second part of this study was designed to determine whether the identity of quality outliers among all of the 32 hospitals in the CSRS database would change after adjusting for the effects of case mix on the SMR. The SMR associated with the case mix of each hospital in the CSRS database (the hospital case mix SMR) was obtained using a resampling algorithm. The hospital SMR (as well as 95% confidence interval) was then calculated using bootstrapping for each of the 32 hospitals within the CSRS database. An adjusted SMR was then derived for each hospital by dividing the hospital SMR by the case mix SMR for that hospital.
Thirty-two hospitals in New York State performing CABG surgery.
None.
Changes in patient case mix are associated with statistically significant changes in the SMR. However, there was no difference in the identity of quality outliers in the New York State CSRS database when using either the SMR or the SMR adjusted for the effects of case mix.
Risk-adjusted measures of outcomes in CABG patients may be potentially biased by differences in case mix between institutions because of the influence of case mix on the process of risk adjustment. There was, however, no evidence of bias in the specific application of the CSRS model to the hospitals in the CSRS database.
基于纽约州心脏手术报告系统（CSRS）预测模型，评估使用标准化死亡比（SMR）比较各医院冠状动脉旁路移植术（CABG）结局的有效性。
本研究设计为一项回顾性研究，基于一个包含1996年在纽约州医院接受单纯CABG手术的所有患者的数据库（n = 20,078）。在本研究的第一部分，使用计算机模拟来评估病例组合差异对SMR的影响。使用一种计算密集型算法从CSRS数据库中的患者创建5000个随机病例组合。使用重采样算法计算与这5000个病例组合中的每一个相关的SMR。本研究的第二部分旨在确定在调整病例组合对SMR的影响后，CSRS数据库中所有32家医院中质量异常值的身份是否会改变。使用重采样算法获得与CSRS数据库中每家医院的病例组合相关的SMR（医院病例组合SMR）。然后使用自举法为CSRS数据库中的32家医院中的每一家计算医院SMR（以及95%置信区间）。然后通过将医院SMR除以该医院的病例组合SMR，为每家医院得出调整后的SMR。
纽约州进行CABG手术的32家医院。
无。
患者病例组合的变化与SMR的统计学显著变化相关。然而，在使用SMR或针对病例组合影响进行调整的SMR时，纽约州CSRS数据库中质量异常值的身份没有差异。
由于病例组合对风险调整过程的影响，CABG患者结局的风险调整测量可能因机构间病例组合的差异而存在潜在偏差。然而，没有证据表明CSRS模型在CSRS数据库中的医院的具体应用存在偏差。
