Relationship between hepatitis C virus infection and type 2 diabetes mellitus: Meta-analysis

Table 1 Preferred reporting items for systematic reviews and meta-analysis reporting

Section/topic	No.	Checklist item	Reported on page
TITLE
Title	1	Identify the report as a systematic review, meta-analysis, or both	Title: Meta-analysis
ABSTRACT
Structured summary	2	Provide a structured summary including, as applicable: background; objectives; data sources; study eligibility criteria, participants, and interventions; study appraisal and synthesis methods; results; limitations; conclusions and implications of key findings; systematic review registration number	Abstract
INTRODUCTION
Rationale	3	Describe the rationale for the review in the context of what is already known	Introduction
Objectives	4	Provide an explicit statement of questions being addressed with reference to participants, interventions, comparisons, outcomes and study design	Introduction
METHODS
Protocol and registration	5	Indicate if a review protocol exists, if and where it can be accessed (e.g., Web address), and, if available, provide registration information including registration number	NA
Eligibility criteria	6	Specify study characteristics (e.g., PICOS, length of follow-up) and report characteristics (e.g., years considered, language, publication status) used as criteria for eligibility, giving rationale	Methods: Search strategy and eligibility of relevant studies
Information sources	7	Describe all information sources (e.g., databases with dates of coverage, contact with study authors to identify additional studies) in the search and date last searched	Methods: Search strategy and eligibility of relevant studies
Search	8	Present full electronic search strategy for at least one database, including any limits used, such that it could be repeated	Search strategy
Study selection	9	State the process for selecting studies (i.e., screening, eligibility, included in systematic review, and, if applicable, included in the meta-analysis)	Methods: Eligibility of relevant studies; PRISMA flowchart provided
Data collection process	10	Describe method of data extraction from reports (e.g., piloted forms, independently, in duplicate) and any processes for obtaining and confirming data from investigators	Methods: Data extraction and outcome measures
Data items	11	List and define all variables for which data were sought (e.g., PICOS, funding sources) and any assumptions and simplifications made
Risk of bias in individual studies	12	Describe methods used for assessing risk of bias of individual studies (including specification of whether this was done at the study or outcome level), and how this information is to be used in any data synthesis
Summary measures	13	State the principal summary measures (e.g., risk ratio, difference in means)	Methods: Statistical analysis
Synthesis of results	14	Describe the methods of handling data and combining results of studies, if done, including measures of consistency (e.g., I2) for each meta-analysis

PICOS: Participants, interventions, comparisons, outcomes and study design; PRISMA: Preferred reporting items for systematic reviews and meta-analysis; NA: Not available.

Table 2 Characteristics of the included studies

Study	Country	Type of study	Age, yr (mean ± SD)	Confirmation of HCV	Confirmation of T2D
Akbar et al[40]	Saudi Arabia	CC	94% had > 402	Anti-HCV	FBS
Antonelli et al[41]	Italy	CC	65 ± 10	Anti-HCV, HCV RNA	FPG
Arao et al[42]	Japan	CC		Anti-HCV, HCV RNA	Random, FBG
Boschi-Pinto et al[43]	Japan	Cohort	65% had > 542	Anti-HCV	Nil
Butt et al[44]	United States	Cohort	50.82		ICD-9
Caronia et al[45]	Italy	CC	57.5 ± 8	Anti-HCV	FPG
Chehadeh et al[8]	Kuwait	Cohort	51 (23-73)3	HCV RNA	FPG
Chen et al[46]	Taiwan	CS		Anti-HCV
Gulcan et al[47]	Turkey	CC	56.89 ± 11.9	Anti-HCV, HCV RNA	Guideline5
Howard et al[48]	United States	CS	51 (37-75)3	Anti-HCV, HCV RNA	Patient reported, FPG
Huang et al[49]	Taiwan	CC	52.7 ± 0.73	Anti-HCV, HCV RNA	FPG
Imazeki et al[50]	Japan	CC	45 ± 16.5	Anti-HCV, HCV RNA	FBS
Jadoon et al[51]	Nigeria	Cohort	48.19 ± 10.32	Anti-HCV	Clinic diagnosed
Kaabia et al[52]	Tunisia	CS	55.62	Anti-HCV, HCV RNA	Patient reported
Knobler et al[53]	Israel	CC	54 ± 14	HCV RNA	FPG
Lecube et al[54]	Spain	Cohort	52.9 ± 14.1	Anti-HCV, HCV RNA	FPG
Li-Ng et al[55]	United States	Cohort	30-794	HbsAg1	ICD-9
Mason et al[5]	United States	CS	72% had > 37	Anti-HCV	FPG, Random
Marzouk et al[56]	Egypt	Cohort	> 252	Anti-HCV, HCV RNA	FBS
Mehta et al[57]	United States	CS	> 202	Anti-HCV	FPG
Nwokediuko et al[58]	Nigeria	CS	55.8 ± 11.84	Anti-HCV	FPG
Okan et al[59]	Turkey	CS	51.92	Anti-HCV, HCV RNA	Nil
Olokoba et al[60]	Nigeria	CS	51.5 ± 12	Anti-HCV	FBS
Papatheodoridis et al[7]	Greece	Cohort	48.1 ± 15.3	Anti-HCV, HCV RNA	FPG
Qureshi et al[61]	Pakistan	CS	42 ± 13	Anti-HCV	Random
Rouabhia et al[62]	Pakistan	CS	55 ± 9	Anti-HCV, HCV RNA	FPG
Ryu et al[63]	Korea	Cohort	44 ± 14	Anti-HCV	FPG
Sangiorgio et al[64]	Italy	CS		Anti-HCV
Simó et al[65]	Spain	CC	46.4 ± 21.2	Anti-HCV	WHO
Wang et al[66]	Taiwan	Cohort	50.9 ± 14.2	Anti-HCV	FPG
Wang et al[67]	China	CC	50.9 ± 14.2	HCV RNA	FBS

¹For HBV infection;

²Mean;

³Mean and range;

⁴Range only;

⁵American Diabetes Association Guideline. CC: Case-control study; CS: Cross-sectional study; FPG: Fasting plasma glucose; FBS: Fasting blood sugar; IFG: Impaired fasting glycaemic; HCV: Hepatitis C virus; T2D: Type 2 diabetes mellitus; HbsAg: Hepatitis B surface antigen; ICD-9: International Classification of Diseases, Ninth Revision; WHO: World Health Organization.

Table 3 Stratified analysis of type 2 diabetes mellitus in hepatitis C virus-infected participants

Description	Cases	OR	95% CI
Age (k = 3; n = 599)	455 vs 144	7.39	5.82-9.38
≥ 40 yr
< 40 yr
BMI (k = 3; n = 190)	65 vs 190	0.87	0.08-9.19
≥ 27
< 27
Gender (k = 8; n = 757)	401 vs 356	1.26	1.03-1.54
Male
Female
Family history of diabetes (k = 3; n = 580)	420 vs 164	4.64	0.57-38.04
Yes
No

OR: Odds ratio; BMI: Body mass index; k: Number of primary studies; n: Number of participants.