0
Correspondence |

ResponseResponse FREE TO VIEW

John P. Reilly, MD; Jason D. Christie, MD
Author and Funding Information

From the Division of Pulmonary, Allergy, and Critical Care (Drs Reilly and Christie) and the Center for Clinical Epidemiology and Biostatistics (Dr Christie), Perelman School of Medicine at the University of Pennsylvania.

CORRESPONDENCE TO: John P. Reilly, MD, 5005 Gibson Bldg, 3400 Spruce St, Philadelphia, PA 19104; e-mail: John.Reilly@uphs.upenn.edu


FINANCIAL/NONFINANCIAL DISCLOSURES: The authors have reported to CHEST that no potential conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.

Reproduction of this article is prohibited without written permission from the American College of Chest Physicians. See online for more details.


Chest. 2015;147(2):e67-e68. doi:10.1378/chest.14-2627
Text Size: A A A
Published online
To the Editor:

We thank Dr Zhan for his interest in our recent article in CHEST1 and for providing the opportunity to discuss our findings of an association between ABO blood type A and increased risk of ARDS in the critically ill.1 First, Dr Zhan’s suggestion that sex may modify the association between ABO blood type and ARDS risk is reasonable because previous research has identified sex differences in the same soluble glycoproteins that are associated with both ABO blood types and ARDS.2 However, we did not detect effect modification by sex in either of our populations. Second, we agree that accurate estimations of adjusted relative risks (ARRs) can be obtained given the prospective cohort design of our study. Using postestimation marginal analysis, the adjusted logistic regression models can be used to estimate ARRs with accurate CIs.3 Based on this approach, the ARRs for the association of blood type A and ARDS among subjects of European descent are 1.52 (95% CI, 1.09-2.13; P = .013) in the trauma cohort and 1.40 (95% CI, 1.05-1.85; P = .021) in the sepsis cohort. Log-linear regression models, another method of estimating ARRs assuming a Poisson distribution,4 result in nearly identical ARR estimates, 1.52 (95% CI, 1.09-2.12; P = .014) in the trauma cohort and 1.39 (95% CI, 1.04-1.86; P = .027) in the sepsis cohort.

Dr Zhan also raises the concern that diabetes, alcohol use, and chronic heart failure may lie within the causal pathway of the ABO and ARDS relationship and, therefore, should not be included in adjusted analyses. Of these three covariates, we included only diabetes in the final multivariable models, because ABO blood types have been associated with risk of diabetes in prior studies.5 Removing diabetes from the logistic regression model does not significantly alter any effect estimates of the association of blood type A and ARDS (ARR 1.53 in trauma, 1.39 in sepsis), suggesting that diabetes is neither a confounder nor a causal mediator. This was also true when all three variables were either included or excluded from multivariable models. Therefore, although ABO blood types have been associated with risk of vascular disease and diabetes,5,6 we do not believe the increased risk of ARDS is mediated through these diseases. ARDS develops in the setting of significant environmental insult (eg, trauma or sepsis), resulting in dramatic activation of endothelium and the inflammatory system. Endothelial-derived glycoproteins linked to ABO blood type, including von Willebrand factor, ICAM-1, and the selectins, are released and/or upregulated by critical illness and may provide the mechanistic link between ABO blood type and ARDS.

References

Reilly JP, Meyer NJ, Shashaty MGS, et al. ABO blood type A is associated with increased risk of ARDS in whites following both major trauma and severe sepsis. Chest. 2014;145(4):753-761. [CrossRef] [PubMed]
 
Blann AD, Daly RJ, Amiral J. The influence of age, gender and ABO blood group on soluble endothelial cell markers and adhesion molecules. Br J Haematol. 1996;92(2):498-500. [CrossRef] [PubMed]
 
Localio AR, Margolis DJ, Berlin JA. Relative risks and confidence intervals were easily computed indirectly from multivariable logistic regression. J Clin Epidemiol. 2007;60(9):874-882. [CrossRef] [PubMed]
 
Zou G. A modified poisson regression approach to prospective studies with binary data. Am J Epidemiol. 2004;159(7):702-706. [CrossRef] [PubMed]
 
Qi L, Cornelis MC, Kraft P, et al. Genetic variants in ABO blood group region, plasma soluble E-selectin levels and risk of type 2 diabetes. Hum Mol Genet. 2010;19(9):1856-1862. [CrossRef] [PubMed]
 
Reilly MP, Li M, He J, et al; Myocardial Infarction Genetics Consortium; Wellcome Trust Case Control Consortium. Identification of ADAMTS7 as a novel locus for coronary atherosclerosis and association of ABO with myocardial infarction in the presence of coronary atherosclerosis: two genome-wide association studies. Lancet. 2011;377(9763):383-392. [CrossRef] [PubMed]
 

Figures

Tables

References

Reilly JP, Meyer NJ, Shashaty MGS, et al. ABO blood type A is associated with increased risk of ARDS in whites following both major trauma and severe sepsis. Chest. 2014;145(4):753-761. [CrossRef] [PubMed]
 
Blann AD, Daly RJ, Amiral J. The influence of age, gender and ABO blood group on soluble endothelial cell markers and adhesion molecules. Br J Haematol. 1996;92(2):498-500. [CrossRef] [PubMed]
 
Localio AR, Margolis DJ, Berlin JA. Relative risks and confidence intervals were easily computed indirectly from multivariable logistic regression. J Clin Epidemiol. 2007;60(9):874-882. [CrossRef] [PubMed]
 
Zou G. A modified poisson regression approach to prospective studies with binary data. Am J Epidemiol. 2004;159(7):702-706. [CrossRef] [PubMed]
 
Qi L, Cornelis MC, Kraft P, et al. Genetic variants in ABO blood group region, plasma soluble E-selectin levels and risk of type 2 diabetes. Hum Mol Genet. 2010;19(9):1856-1862. [CrossRef] [PubMed]
 
Reilly MP, Li M, He J, et al; Myocardial Infarction Genetics Consortium; Wellcome Trust Case Control Consortium. Identification of ADAMTS7 as a novel locus for coronary atherosclerosis and association of ABO with myocardial infarction in the presence of coronary atherosclerosis: two genome-wide association studies. Lancet. 2011;377(9763):383-392. [CrossRef] [PubMed]
 
NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging & repositioning the boxes below.

Find Similar Articles
  • CHEST Journal
    Print ISSN: 0012-3692
    Online ISSN: 1931-3543