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PREVALENCE AND PREDICTORS OF OBESITY AMONG INDIVIDUALS WITH POSITIVE HEPATITIS C ANTIBODY IN A TERTIARY REFERRAL CLINIC
W Chen, T Wong, G Tomlinson, M Krahn, EJ Heathcote
Department of health policy, management and evaluation, University of Toronto
BACKGROUND: Obesity is associated with hepatic steatosis and poor response to anti-viral therapy in patients with chronic hepatitis C virus (HCV) infection. The prevalence of obesity in HCV infected individuals is unknown. Aims: To determine the prevalence of obesity, and investigate factors associated with obesity in a HCV antibody positive clinic population.
METHODS: We reviewed patient records describing visits to a downtown tertiary care liver clinic in Toronto, Canada between 1990 and 2006. We performed three comparisons. First, we compared the prevalence of obesity to age- and sex- stratified samples of the Canadian population. Second, we used regression analysis to explore factors associated with obesity in this clinic population. Third, we compared the prevalence of obesity among propensity matched HCV positive and HCV negative patients selected from this clinic population.
RESULTS: 1118 out of 3505 patients met our inclusion criteria. The prevalence of obesity was 28.8%; nearly double that of the Canadian general population (14.9%) in 2001. In multiple regression analyses, older age (odds ratio (OR) 1.02; 95% confidence interval (CI) 1.00 to 1.04) and a positive HCV ribonucleic acid (RNA) test (OR 1.80; 95% CI 1.11 to 2.92) were independent predictors of obesity. In the third analysis, comparing 112 propensity matched pairs, the proportion with obesity was significantly higher among HCV RNA positive patients than in matched patients who tested negative (32.1% vs. 18.8%; p=0.02), but the difference in BMI between groups (mean ± standard deviation: 27.6 ± 5.4 vs. 26.6 ± 4.8) was not significant. Supplemental analyses which excluded patients with presumed fatty liver disease (i.e.: HCV RNA negative with elevated alanine aminotransferase) showed significant increases of both BMI and obesity among patients with HCV RNA positive status in both multiple regression analyses (BMI: coefficients 1.12, p=0.03; obesity: OR 2.53, 95% CI 1.38-4.66) and propensity score analysis for 101 matched pairs (BMI: 27.1 ± 5.7 vs. 25.6 ± 3.9, p=0.03; obesity: 30.7% vs. 12.9%, p=0.002).
CONCLUSION: Obesity is common in a clinic population testing positive for HCV antibody, and may be more prevalent than in the general population. The presence of HCV viremia may be associated with increased risk of obesity.
This project is funded by National Canadian Research Training Program in Hepatitis C and Canadian Liver Foundation