With great interest we read the recent publication in Hepatology by Ruhl et al., who concluded that elevated liver enzyme activities were associated with both diabetes and insulin resistance but no association of hepatitis C virus (HCV) infection with diabetes or with insulin resistance was observed. This national epidemiological large-sample study had wide implications in the field of hepatology and endocrinology. However, in our opinion, the study raises certain questions.
As demonstrated by many studies,[2-4] liver function or disease progression played an important role in the development of diabetes in HCV-infected patients; in other words, these patients with hepatic decompensation or cirrhosis seemed liable to develop diabetes. We conducted a similar study in our hospital which enrolled a total of 467 patients with chronic HCV infection from January 2011 to December 2013 and found that a statistical significance (92/211 versus 55/256, P < 0.01) existed in the distribution of diabetes in patients with and without hepatic decompensation (Fig. 1). Additionally, the authors only selected liver enzymes as the independent factors in the analysis and did not include other common important indicators, such as bilirubin, lipid, and albumin, which might impact the outcomes of the logistic regression. A previous study by Liu et al. demonstrated that whether the relationship between HCV and type 2 diabetes existed or not was influenced by the inclusion of the lipid level in the analysis.
In summary, liver function was a vital confounding factor in the analysis of association of HCV infection with diabetes. We suggest that the authors add the indicators which proved to be closely associated with liver function into the logistic regression analysis or divide the participants into different groups according to liver function or disease progression.
Pan Zhao, M.D., Ph.D.1,2
Zhenman Wei, M.D.1
Wanshu Liu, M.B.2
1Clinical Trial Center Beijing 302 Hospital Beijing, China
2Liver Failure Therapy and Research Center Beijing 302 Hospital Beijing, China