Fate of meta-analyses: The case of Helicobacter pylori

Table 1 Number of meta-analyses published on selected topics (from PubMed, accessed on September 30, 2014)

Topic/field	No. of meta-analyses
Diabetes mellitus	3245
Hypertension	2964
Coronary heart disease	3159
Gastrointestinal cancer	2787
Statins	957
Hepatitis C	550
Liver cirrhosis	435
Proton pump inhibitors	356
Helicobacter pylori	356
Peptic ulcer	395
Gastroesophageal reflux	231

Table 2 Profile and No. of published meta-analyses and systematic reviews on Helicobacter pylori

Topic	Total No. of publications	Meta-analyses	Systematic reviews	Meta-analysis + systematic review
Epidemiology	6	5	1	0
Diagnosis	23	13	4	6
Antibiotic resistance	7	5	2	0
Genetics	32	30	0	2
Eradication regimens	134	98	17	19
Extragastric manifestations	49	35	2	12
Probiotics	11	11	0	0
Peptic ulcer	9	7	1	1
Gastric cancer	16	12	0	4
Pathogenesis	22	21	1	1
Other cancers (oesophagus, colon, pancreas, liver, biliary, lung)	26	24	0	2
Children	8	7	0	1
Methodological issues	12	0	12	0
Traditional Chinese medicine	1	0	0	1
Total	356	268 (75.2%)	40 (11.3%)	48 (13.4%)

Table 3 Core journals publishing meta-analyses and systematic reviews on Helicobacter pylori

Title	No. of meta-analyses	Impact factor (2013)
Alim Pharmacol Ther	45	5.478
Helicobacter	27	2.993
World J Gastroenterol	25	2.433
Am J Gastroenterol	21	9.131
Plos ONE	14	3.534
BMJ	11	16.378
Eur J Gastroenterol Hepatol	10	2.152
Total	153	Not applicable

Table 4 Implementation of meta-analyses in international consensus guidelines

Year	Consensus meeting	No. of ref.	No. of meta-analyses/systematic reviews cited
2007	Maastricht III consensus	99	10 (9.9%)
2007	Cervia II Working Group guideline	72	5 (6.5%)
2007	American College of Gastroenterology guideline	175	23 (13.1%)
2009	Second Asia-Pacific Consensus Guidelines	118	12 (10.1%)
2012	Maastricht-Florence 4 guideline	325	36 (11.0%)
2013	3rd Brazilian Consensus	216	25 (11.3%)
2013	Revised Korean consensus	208	19 (9.3%)
	Total	1223	130 (10.6%)

Table 5 Citation of meta-analyses in recent expert reviews

Ref.	Year	Journal	No. ref.	No. and % of meta-analyses cited
[20]	2014	World J Gastroenterol	115	5 (4.3)
[21]	2014	World J Gastroenterol	137	8 (5.8)
[22]	2014	World J Gastroenterol	158	14 (8.8)
[23]	2014	World J Gastroenterol	69	1 (1.4)
[24]	2014	World J Gastroenterol	79	14 (17.7)
		Total	558	42 (7.5)

Table 6 Citation of randomly selected meta-analyses on Helicobacter pylori (Web of Science, accessed on September 4, 2014)

Ref.	Year	Journal	Total citations	Independent citations
[24]	2006	Aliment Pharmacol Ther	172	172
[25]	2009	Am J Gasteroenterol	127	127
[26]	2009	Helicobacter	84	84
[27]	2010	Am J Gastroenterol	62	62
[28]	2010	Am J Gastroenterol	43	43