Online Letters to the Editor

Do-Not-Resuscitate: Another Effect of Rapid Response Team To the Editor:

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n a recent issue of Critical Care Medicine, we read with great interest the article by Karpman et al (1) who investigated the impact of rapid response team (RRT) on the outcome of patients transferred from the ward to the ICU (1). They found that the implementation of RRT was associated with increasing ICU admission; however, this measure did not improve the severity-of-illness-adjusted outcome. Although Karpman et al (1) had multiple potential explanations for their finding in the text, we suggest that there should be one more cause which is needed to be taken into consideration. As we know, an intensivist-led RRT would be associated with increasing ratio of donot-resuscitate (DNR) order and decreasing futile resuscitation. Furthermore, the more DNR order was associated the more ICU mortalities. Therefore, it would be possible that if the implementation of RRT results in more DNR orders, the positive impact of RRT on outcome of ICU admission patient may be weaken. To clarify this issue, Karpman et al (1) had better show the ratio of DNR order during per-RRT and RRT period. In fact, in addition to the ICU mortality or the length of ICU stay, the decreasing ratio of DNR order should be another effect of RRT. The authors have disclosed that they do not have any potential conflicts of interest. Chia-Chang Kuo, MD, Department of Emergency Medicine, Tainan Municipal Hospital, Tainan, Taiwan; Chien-Ming Chao, MD, Department of Intensive Care Medicine, Chi-Mei Medical Center, Liouying Tainan, Taiwan

REFERENCE

1. Karpman C, Keegan MT, Jensen JB, et al: The Impact of Rapid Response Team on Outcome of Patients Transferred From the Ward to the ICU: A Single-Center Study. Crit Care Med 2013; 41:2284–2291 DOI: 10.1097/01.ccm.0000435670.37941.67

Does the Association Between a High Body Mass Index and Hospital Mortality Weigh “Heavily” on the Association Between a Low Body Mass Index and Hospital Mortality? To the Editor:

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n a recent issue of Critical Care Medicine, Pickkers et al (1) have reported that an inverse relationship exists between body mass index (BMI) and in-hospital mortality in

Copyright © 2013 by the Society of Critical Care Medicine and Lippincott Williams & Wilkins

Critical Care Medicine

patients admitted to an ICU. This is an important observation, given the fact that in the general population, a BMI both below and above the optimum is actually associated with mortality (2). To reduce the influence of potential confounders on the association between BMI and in-hospital mortality, the authors could perform a couple of additional analyses. First, the relationship between BMI and in-hospital mortality may differ between different ICU patient categories. Given the large number of patients included in their database, they could investigate potential differences in the association between BMI and in-hospital mortality in diverse ICU populations. Second, the authors used a multivariate logistic regression analysis to investigate the relationship between BMI and the inhospital mortality rate and included a number of potential confounders in the statistical model. BMI was included in the model after restricted regression spline transformation. As can be appreciated by inspecting Figure 2 in (1), which shows the estimated association of BMI and in-hospital mortality, the model could have been influenced by the greatly increased risk of mortality in underweight patients. Also, we should take in mind that a logarithmic scale is used. Could the very strong association between a low BMI and in-hospital mortality have influenced the trajectory of the curve for normal and overweight patients when using spline transformation (3). To overcome this uncertainty, we propose a more parsimonious approach to investigate the relationship between BMI and in-hospital mortality, for example, investigating in-hospital mortality rates using BMI as a categorical variable and using a BMI between 18.5 and 24.9 kg/ m2 as the reference value. Using this approach, the association between BMI and in-hospital mortality will not be deformed, as it could potentially be when using spline transformation. Dr. Klopper is employed by Academic Medical Center, Amsterdam. All authors have disclosed that they do not have any potential conflicts of interest. Bimmer E. Claessen, MD, PhD, Kai E. Klopper, MD, Marcus J. Schultz, MD, PhD, FCCP Department of Intensive Care Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands

REFERENCES

1. Pickkers P, de Keizer N, Dusseljee J, et al: Body Mass Index Is Associated With Hospital Mortality in Critically Ill Patients: An Observational Cohort Study. Crit Care Med 2013; 41:1878–1883 2. Whitlock G, Lewington S, Sherliker P, et al; Prospective Studies Collaboration: Body-mass index and cause-specific mortality in 900 000 adults: Collaborative analyses of 57 prospective studies. Lancet 2009; 373:1083–1096 3. Belot A, Abrahamowicz M, Remontet L, et al: Flexible modeling of competing risks in survival analysis. Stat Med 2010; 29: 2453–2468 DOI: 10.1097CCM.0000000000000011 www.ccmjournal.org

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Does the association between a high body mass index and hospital mortality weigh "heavily" on the association between a low body mass index and hospital mortality?

Does the association between a high body mass index and hospital mortality weigh "heavily" on the association between a low body mass index and hospital mortality? - PDF Download Free
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