Table 1.

Main characteristics of the studies included in this meta-analysis

Ref.	Country	Study design	Year	Total number	Study sample	Exposure definition	Exposure measurement	Outcome definition	Outcome ascertainment	Adjusted OR	Confounder adjustment	Quality assessment (Newcastle-Ottawa scale)
Amin et al[16]	Australia	Cohort study	2006	75834 in HCV patients	People notified with HCV infection to the New South Wales Health Department’s Notifiable Diseases Database between 1 January 1990 and 31 December 2002 (HCV group) and NSW population (control group)	HCV infection	Detection of anti-HCV antibody or HCV RNA	Renal cancer or kidney cancer	The NSW Central Cancer Registry with ICD-10 code C64 for kidney cancer and C65 for renal cancer	Kidney cancer 0.9 (0.6–1.4)	Age, sex and calendar year	Selection: 4 Comparability: 1 Outcome: 3
Malagu arnera et al[21]	Italy	Case control study	2006	315 (15 case and 300 control)	Elderly kidney cancer patients attending geriatric department (case) and elderly volunteers (control)	Positive Anti-HCV	Detection of Anti-HCV antibody using enzyme-linked immunosorbent assay. Assay positive samples were confirmed by immunoblotting	Kidney cancer	N/A	10.29 (3.49-30.36)	None	Selection: 3 Comparability: 0 Outcome: 2
Omland et al[22]	Denmark	Cohort study	2010	4204 in HCV patients	Acute or chronic HCV infected patients listed in the Danish National Hospital Registry between 1994 and 2003 without previous diagnosis of cancer (HCV) and general population (control)	Acute or chronic HCV infection	ICD-10 code (B17.1 and B18.2) from the Danish National Hospital Registry	Kidney cancer	The Danish Cancer Registry with ICD-7 code 180	3.60 (0.98–9.22)	Age, sex and year of diagnosis	Selection: 4 Comparability: 1 Outcome: 2
Gordon et al[19]	United States	Cohort study	2010	67063	HCV-tested patients (both positive and negative) between 1997 and 2006 from administrative data from Henry Ford hospital	HCV infection	Positive anti-HCV test using enzyme-linked immunosorbent assay, confirmed by a documented positive molecular assay for HCV RNA	Renal cell carcinoma	Health system cancer registry, confirmed by medical record and pathology report review	1.77 (1.05-2.98)	Age, race, gender, chronic kidney disease	Selection: 4 Comparability: 1 Outcome: 3
Budakoğlu et al[17]	Turkey	Case-control study	2011	6170 (903 case and 5267 control)	Patients who had histologically proven renal cell carcinoma diagnosis between 2005 to 2010 from six tertiary cancer centers (case) and healthy people who were living in the same geographic regions (control)	Positive anti-HCV	Positive anti-HCV test using enzyme-linked immunosorbent assay	Renal cell carcinoma	Histopathology report	1.08 (0.62-1.88)	None	Selection: 3 Comparability: 0 Outcome: 3
Hofmann et al[20]	Sweden	Cohort study	2011	43000 in HCV patients	All Swedish residents diagnosed with HCV infection between 1990 and 2006 (HCV group) and general population (control)	Chronic HCV infection	The national surveillance database at the Swedish Institute for Infectious Disease Control	Kidney cancer	The national Cancer register with ICD-7 code 180.0 and 180.9 and histologic confirmation	1.2 (0.8–1.7)	Age, sex and calendar year	Selection: 4 Comparability: 1 Outcome: 3
Gonzalez et al[18]	United States	Case-control study	2015	240 (140 case and 100 control)	Newly diagnosed renal cell carcinoma (case) and newly diagnosed colon cancer patients (control)	Chronic HCV infection	Detection of anti-HCV antibody or HCV RNA	Renal cell carcinoma	Histopathology report	Positive HCV RNA 24.20 (2.4 - > 999.9)	Sex, age, race, BMI, smoking, alcohol abuse, hypertension, diabetes mellitus, dyslipidemia, coronary artery disease, congestive heart failure, chronic kidney disease, cirrhosis	Selection: 3 Comparability: 2 Outcome: 3

BMI: Body mass index; DNHR: Danish National Hospital Registry; ELISA: Enzyme-linked immunosorbent assay; HCV: Hepatitis C virus; N/A: Not available; NSW: New South Wales; RCC: Renal cell carcinoma; SIR: Standardized incidence ratio.