Red Cell Distribution Width Cannot Predict Acute Mesenteric Ischemia: Reply

Abstract

To the Editor,We are honored to see that our published article aboutthe relationship between acute mesenteric ischemia (AMI)and red cell distribution width (RDW) took attention [1].Zhang et al. [2] shared their opinions about the topic, andthey deservedly pointed out some blurred details. It is ourmission to clarify these issues:First, RDW is not a specific marker, but a clue thatsomething wrong is going on in the body leading to anincrease in reticulocytes in the blood. There are hundreds ofdifferent physiologic and pathologic conditions that maycauseRDWrise.Inourmethodssection,weclearlyidentifiedthat our exclusion criteria included ‘‘patients with any illnessthat could affect RDW levels, such as thalassemia trait,hereditary elliptocytosis, and hemoglobin C disease’’ [1].Neither the patients with AMI nor control group had renal/hepatic dysfunction, thyroid or bone marrow disease, previ-ous history of transfusion within 3 months, or malnutrition.ThestudygroupsconsistedofTurkishethnicitywithoutusingmedications that may influence RDW. However, we couldnot stabilize some of the comorbidities that were also knownas etiologic factors in AMI such as atrial fibrillation, chronicheartfailure, arterialhypertension, anddiabetesmellitus.Wementioned this point in our limitations section [1].Second, as the study groups were gathered from theemergency department (ED), there were no delay betweenblood sampling and RDW measuring. After the bloodsamples are sent via pneumatic system in our ED, theparameters are measured in a special part of the laboratoryto prevent delays: emergency laboratory part. Thus, wethink that our laboratory procedure has got no influence inRDW measurements.Third, in our first table, there were 13 parameters thatwere significantly different between AMI patients andcontrols. We were analyzing the laboratory parameters ofstudy population, and thus we did not take into accountdemographic features and comorbidities in multivariateanalysis. As some of these laboratory parameters wereassociated with each other, we carefully chosen sevendifferent parameters in the multivariate analysis. Studyingseven parameters as multivariate analysis in a population of159 is very acceptable and enough for the statistical power[1]. In the logistic analysis, we only gave statistically sig-nificant results. The odds ratio of RDW was 1.058 (95 %CI 0.754–1.485; wald: 0.106, p = 0.745).Fourth, Zhang et al. kindly requested the reason ofconflicting results about RDW levels and ischemia/necrosissize and mortality between our study and Bilgic et al.’sstudy [1–3]. Our study has got superiorities discussed to thearticle by Bilgic et al. We measured the size of ischemia/necrosis in centimeters, while they just grouped the patientsaccording to approximate necrosis length without measur-ing the exact size. Moreover, we did not need resectionsurgery in the first look for all the patients with AMIcontrary to their study population. Most important, weexcluded patients with comorbidities that may affect RDW,and for the etiologic factors that may affect this parameter(atrial fibrillation, chronic heart failure, hypertension, anddiabetes mellitus), we discussed them with univariateanalyses between patients with and without mortalities. Wewere unable to see these exclusion criteria and discussionsin the study by Bilgic et al.