Review for 10.1186/s12876-015-0263-9 (2015)

Reviewer's report
Title:Identifying patients with chronic hepatitis B at high risk of type 2 diabetes
mellitus: a case-control study
Version:4Date:10 December 2014
Reviewer: Saurabh Mukewar
Reviewer's report:
Authors have conducted a cross-sectional study comparing chronic hepatitis B
patients with diabetes and those without. Results show that patients with chronic
hepatitis B and DM2 have longer duration of illness and higher HBV viral load in
addition to other factors. The strengths of this study are large numbers of
patients with chronic hepatitis B and multiple variables related to hepatitis and
diabetes have been reported. However, the following should to be addressed:
Major comments:
Authors have incorrectly stated the study design. Based on the methodology, this
is not a case control study. Rather, this is a cross sectional study.
Please state that the factors are associated with diabetic patients throughout the
manuscript.
For example:
DISCUSSION
“…In this hospital-based case-control study,
several CHB-associated variables, such as the duration of CHB, HBV viral load
and
cirrhosis, were identified as risk factors for type 2 diabetes in overall analysis…”
I would rather state that CHB-related variables, namely duration of CHB, HBV
viral load and cirrhosis were associated with patients with type 2 DM compared
to those without. Statements suggestive of causality will not be appropriate, as
this was not a cohort study and all these variables are being assessed at one
time point (which is after development of DM2 in majority of the cases).
How many patients were undergoing treatment for CHB? What medications were
used for treatment?
What was the range of HbA1c in controls? Based on the values it appears that
HbA1c was >7 in some controls. What was the reason for adding them in the
“control” group ?
When were labs drawn ? At time of enrollment in study ?
Background:
“..The aim of this hospital-based case-control study was to evaluate the
interaction among the different variables and identify distinct and homogeneous
subgroups of CHB patients at high risk of T2DM..”
-- I do not see how “interaction” among different variables is accomplished by this
study. In addition, I would consider refraining form using terms such as “distinct”
and “homogenous” sub-groups. This aim can be restructured as “Aim of this
study was to identify factors associated with type 2 diabetes in patients with
chronic hepatitis B”.
Methods:
“..The interview included questions related to the diagnosis and treatment of
diabetes
and hepatitis ..” How many patients were undergoing treatment for DM2? What
medications were used for treatment?
Please justify exclusion of patients with family history of type 2 diabetes. Given,
that this is a cross sectional study and causality cannot be ascertained, patients
with family history of type 2 DM should not be excluded.
STAT ANALYSIS:
“..Risk factors found significant on univariate analysis were entered into
multivariate analysis by logistic regression analysis..”- Shouldn’t all the plausible
risk factors taken into the analysis ?
Minor comments:
METHODS:
Page 6, line 3: change “length” to “height”; “marriage status” to “marital status”.
Please define each variable: example education level (high school …. Etc.) or
marriage status (Yes/No)..
Ciggaretts spelling mistake.
Table: Show data in percentages.
Duration of CHB ? Is it 10 or 10 to 15 ?
DISCUSSION:
“..Multivariate-adjusted Logistic analysis further confirmed that high viral load
(HBV DNA #106copies/mL) was an independent risk factor of diabetes for the
CHB patients..”
-- Again would suggest not using the term “risk factor” but instead state that high
viral load was independently associated with DM2 in patients with CHB.
Please cite references where appropriate: eg. Page 12 last paragraph. “..In
agreement with previous studies among general population, elevated serum
triglyceride level and lower educational level were also significantly associated
with an increased risk of diabetes among these CHB patients..”
Articles to cite:
Tkachenko LI, Maleev VV. [Clinical features of chronic hepatitis B in the
presence of metabolic syndrome and insulin resistance]. Ter Arkh.
2014;86(8):18-22. Russian. PubMed PMID: 25306739.
Chen CL, Yang HI, Yang WS, Liu CJ, Chen PJ, You SL, Wang LY, Sun CA, Lu
SN, Chen DS, Chen CJ. Metabolic factors and risk of hepatocellular carcinoma
by chronic hepatitis B/C infection: a follow-up study in Taiwan. Gastroenterology
2008; 135: 111-121 [PMID: 18505690]
Lai MS, Hsieh MS, Chiu YH, Chen TH. Type 2 diabetes and hepatocellular
carcinoma: A cohort study in high prevalence area of hepatitis virus infection.
Hepatology 2006; 43: 1295-1302 [PMID: 16729295]
Hsiang JC, Wong GL, Chan HL, Chan AW, Chim AM, Wong VW. Metabolic
syndrome delays HBeAg seroclearance in Chinese patients with hepatitis B.
Aliment Pharmacol Ther. 2014 Sep;40(6):716-26. doi: 10.1111/apt.12874. Epub
2014 Jul 13. PubMed PMID: 25039861.
Wang CC, Hsu CS, Liu CJ, Kao JH, Chen DS. Association of chronic hepatitis B
virus infection with insulin resistance and hepatic steatosis. J Gastroenterol
Hepatol 2008; 23: 779-782
[PMID: 18028349]
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Not suitable for publication unless extensively edited
Statistical review: Yes, but I do not feel adequately qualified to assess the
statistics.
Declaration of competing interests:
I declare that I have no competing interests