Active Smoking Is Associated with Positive Video Capsule Endoscopy for Iron Deficiency Anemia

Abstract

Introduction: Iron deficiency anemia (IDA) occurs in 2-5% of adult men and postmenopausal women accounting for 4-13% of referrals to a gastroenterologist. Following upper and lower endoscopy, video capsule endoscopy (VCE) is recommended in cases with an inadequate response to iron therapy or requirement of transfusion. This study aims to define clinical predictive factors for positive VCE in the setting of IDA in order to improve recommendations for the performance of VCE. Methods: Data was collected fromconsecutive inpatient and outpatient VCE examinations performed between January 1, 2009 to March 1, 2018 from two U.S. tertiary medical centers. VCE studies were excluded for being incomplete (15), technical failures (4) or for being performed for indications other than IDA (158). Patient demographics, laboratory values, medication use and endoscopic findings were obtained for additional analysis. VCE findings were based on the P0-P2 grading system. The primary outcome of interest was a positive (P2) VCE. Data were analyzed using Wilcoxon rank-sum test for continuous variables and Fischer's exact test for dichotomous variables. Multivariate logistic regression was performed to identify independent factors predictive of positive VCE. Results: Five-hundred thirty-six VCE were included in the final analysis. One-hundred forty-nine (27.8%) were positive examinations (P2). Two-hundred seventy (50.3%) cases were performed as inpatient examinations with a median time to VCE of 4 days (IQR: 2-6). Risk factors for positive VCE are listed in Table 1. In multivariate analysis, active smoking (OR: 1.85, 95% CI: 1.04-3.28) and hemoglobin (OR: 0.78, 95% CI: 0.69-0.89) were predictive of positive VCE. Among active smokers, 36/85 (42.4%) VCE were positive as compared to 112/446 (25.1%) positive VCE among non-smokers. Conclusion: Positive VCE for IDA is associated with active smoking in univariate and multivariate analysis and inversely related to pre-procedure hemoglobin. Identifying a modifiable target allows for interventions aimed at reducing anemia recurrence. Future studies should focus on the role of smoking cessation programs for recurrent IDA.1170 Figure 1. Univariate and multivariate analysis.