Lewis blood group phenotype vis-a-vis biochemical and physiological parameters of coronary artery disease: A study in North Indian population

Background: Many studies have proposed the lack of Lewis antigen as a marker for coronary artery disease (CAD); on the contrary, some of the studies found no association in this regard. This study aims to assess the association of the expression of Lewis antigen as an independent risk factor for CAD separately in males and females. Materials and Methods: In this cross-sectional observational study, patients with angiographically proven CAD were taken as test group, and angiographically, negative patients were included as a control group. The individuals were examined for established CAD risk factor and Lewis antigen expression on red cell. Red cell Lewis phenotyping was done using microcolumn gel agglutination technology. Statistical tests were applied to see the association between lack of Lewis antigen expression and CAD. Results: Of these 232 patients included in the study, 161 patients had more than 50% luminal stenosis in a major epicardial artery on coronary angiography (Test Group), and 71 were normal on angiography (Control Group). When males and females were considered together, there was an increased frequency of Lewis-negative phenotype among the angiography-positive group (26.7%) as compared to angiography normal control group (16.9 %), though was not statistically significant (P = 0.19). When males and females were segregated in multivariate analysis, Le (a-b-) females had a higher incidence of CAD (P = 0.03) with the odds ratio of 4.97, though an association was not found significant in males (P = 0.71). Conclusion: The association between Lewis phenotypes and CAD was not significant in males and in among the overall study population, but this association was statistically significant in females. Further studies based on a larger sample size may substantiate as well as delineate the possible hypotheses.