Re: Trauma care does not discriminate: The association of race and health insurance with mortality following traumatic injury.
Re: Trauma care does not discriminate: The association of race and health insurance with mortality following traumatic injury.
复制标题
回复:创伤护理不歧视:种族和健康保险与创伤后死亡率的关系。
DOI:
10.1097/ta.0000000000000779
复制
发表时间:
2015
期刊:
影响因子:
--
通讯作者:
Millham,Frederick
中科院分区:
文献类型:
--
作者:
Osler,Turner;Glance,LaurentG;Li,Wenjun;Buzas,JefferyS;Wetzel,MeganL;Hosmer,DavidW;Millham,Frederick
In Reply: We appreciate Dr. Zafar’s interest in our work and thank the Journal of Trauma and Acute Care Surgery for the opportunity to comment on his questions and concerns. We are pleased that Dr. Zafar found our use of imputed insurance status to address survivor treatment assignment bias to be a novel addition. We hope others will also find it useful in their research. Although we failed to emphasize it in our article, our observation that the apparent association of insurance coverage with survival is an epiphenomenon rather than a real correlation was an essential prerequisite to our analysis of the importance of race: because race is confounded with insurance coverage (far fewer black patients have insurance), excluding insurance coverage from our final model was crucial to correctly conclude that race is not associated with survival. We agree with Dr. Zafar that the National Trauma Data Bank (NTDB) is a valuable resource; indeed, we have made extensive use of the NTDB in other investigations. However, the National Inpatient Sample (NIS) is also a valuable resource, one that allows us to pose a fundamentally different question. Because the NIS is a stratified sample of 20% of all US hospitals, it is a statistically accurate reflection of all hospital admissions in the United States. It therefore allows us to assess the importance of race and insurance coverage in the entire United States. The NTDB, by contrast, allows only inferences to the hospitals that contribute data to the NTDB.(In passing, we would note that, because the NIS is a stratified sample, it actually contains 20% of the hospitals in the NTDB in addition to the 20% of the other roughly 4,000 hospitals in the United States).Dr. Zafar is concerned that the variables available in the NIS do not allow for adequate risk adjustment. While he agrees that the Trauma Mortality Prediction Model (TMPM1) that we used in our study allows for adequate risk adjustment of anatomic injuries (a point we concur on: TMPM computed on DRG International Classification of DiseasesV9th Rev.[ICD-9] codes actually discriminates survivors from nonsurvivors better than Injury Severity Score [ISS] computed on Abbreviated Injury Scale [AIS] codes), 2 he worries that other important predictors of mortality are not available in the NIS and mentions shock as a particular concern. We initially shared his suspicion that a clinical variable, shock, might not be accurately captured in an administrative data set. However, univariate analysis showed that in the 1% of patients coded in the NIS as having traumatic shock, mortality was much higher (26%) than in the 99% of patients coded as not having traumatic shock who had only a 1.5% mortality. Moreover, in adjusted mortality models, the odds ratio (OR) for traumatic shock was much higher in the elderly (age 9 64 years)(OR, 1.90) than in the young (OR, 1.27), an observation that comports with the clinical experience that the elderly are, in general, less tolerant of shock. After consideration, we concluded that, contrary to our preconceived opinion, ICD-9 code 958.4 may be a very reliable indicator of shock precisely because it is a direct transcription by coders of physicians’ considered diagnosis as written in their notes rather than being an arbitrarily dichotomized value based on a systolic blood pressure. In effect, we have ‘‘crowd sourced’’the diagnosis of shock to knowledgeable physicians rather than relying on a single blood pressure measurement. Our final models were based on careful use of the data available in the NIS and, by the objective measures of discrimination and calibration, were very reliable. As we note in the online appendix to our article, the logistic model for young …