When policy meets statistics - The very real effect that questionable statistical analysis has on limiting health care access for bariatric surgery
When policy meets statistics - The very real effect that questionable statistical analysis has on limiting health care access for bariatric surgery
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DOI：
10.1001/archsurg.142.10.979
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发表时间：
2007-10-01
影响因子：
--
通讯作者：
Engel, Eli
中科院分区：
文献类型：
--
作者：
Livingston, Edward H.;Elliott, Alan C.;Engel, Eli
假设：医疗保险患者的减肥手术必须在每年至少进行 125 例手术的认可医院进行。我们评估了这一容量阈值的有效性及其政策含义。 设计：利用 2001-2003 年全国住院患者调查，对医院容量对住院死亡率的影响进行了统计建模，并计算了每年 125 例阈值对接受减肥手术的影响。我们进行了蒙特卡罗建模，以调查随机抽样对低容量医院明显高死亡率的影响。设置：美国住院医院。患者：出院代码表明接受减肥手术的患者。主要结果指标：院内死亡率。结果：观察到的院内死亡率分布作为医院容量的函数，与单独随机抽样的预期频率相似。容量非常低的设施中的少量超额死亡导致容量结果研究具有统计显着性结果。尽管 74% 的减肥手术是在高容量中心进行的，但目前提供这些服务的所有医院中有 73% 被归类为低容量医院。结论：当统计分析的结果用于政策制定时，对患者护理的影响可能是巨大的。大多数关于成交量结果关系的研究都依赖于倾向于放大影响的统计方法，但很少有充分描述其统计模型的特征。尽管减肥手术与手术量结果关系的证据薄弱，但卓越中心地位的门槛已设定为每年 125 例，这消除了目前提供这些服务的大多数医院，并且不成比例地限制了穷人和保险不足的人获得这些服务。
Hypothesis: Bariatric surgery for Medicare patients must be performed in an accredited hospital that performs at least 125 cases per year. We assessed the validity of this volume threshold and its policy implications.Design: Using the 2001-2003 National Inpatient Survey, the effect of hospital volume on in-hospital mortality was statistically modeled and the effect of a 125-case per year threshold on access to bariatric surgery was calculated. We performed Monte Carlo modeling to investigate the effect random sampling has on the apparently high mortality rate for low-volume hospitals.Setting: US inpatient hospitals.Patients: Patients with hospital discharge codes indicating bariatric surgery.Main Outcome Measure: In-house mortality.Results: The observed in-hospital mortality distribution as a function of hospital volume was similar to theexpected frequency attributable to random sampling alone. A small number of excess deaths in very low-volume facilities cause statistically significant results for volumeoutcome studies. Although 74% of all bariatric surgeries are performed in high-volume centers, 73% of all hospitals currently offering these services are now classified as low volume.Conclusions: When the results of statistical analysis are used for policy determination, the consequences for patient care may be substantial. Most studies of volumeoutcome relationships rely on statistical methods that tend to amplify the effects and few fully characterize their statistical models. Despite the weak evidence for a volumeoutcome relationship for bariatric surgery, a 125-case per year threshold has been set for center-of-excellence status, which eliminates most hospitals currently providing these services and disproportionately restricts access for the poor and underinsured.