Introduction
Bariatric surgery is the most effective method for producing sustained weight loss, improving obesity-associated comorbidities and reducing inflammation in the morbidly obese population. The red cell distribution width (RDW) is a novel marker of inflammation that is usually reported as part of a complete blood count. In this study, we tested our hypothesis that red cell distribution width might represent a novel biomarker predictive of excess body-mass index loss (EBMIL) following laparoscopic Roux-en-Y gastric bypass (LRYGB).
Methods
Five hundred and forty-seven included LRYGB patients from a single institution were individually reviewed, noting both pre-operative RDW and percent excess BMI loss at six months and one year post-LRYGB (%EBMIL180 and %EBMIL365, respectively). Bivariate and multivariate linear regression analysis was conducted between age, gender, initial body-mass index (BMI0) and RDW and each of the two endpoints, to assess the independence of RDW as a predictor of post-operative success.
Results
The median RDW was 13.9 (13.3 – 14.6)%, and median EBMIL180 and EBMIL365 were 55.4 (45.2 – 66.7)% and 71.3 (58.9 – 87.8)%, respectively. After controlling for age, gender and BMI0, RDW was associated with %EBMIL365 (B = −1.4 [−2.8 – −0.002]%, P = .05), but not %EBMIL180 (B = −0.6 [−1.6 – 0.5]%, P = .30. Upon Kruskal-Wallis analysis, patients with a pre-operative RDW > 15.0% had significantly lower %EBMIL than those in the <13.0% (P < .001) and 13.0–15.0% (P < .01) strata.
Conclusions
RDW is predictive of EBMIL at one year following LRYGB. This represents a novel pre-operative biomarker that may provide clinically useful prognostic information.