Supplementary table 1. Additional information on studies’ methodology.

Type of study / Type of patients for second-line /
Author / Year / Country / Type / Design / Age / Disease / Inclusion criteria / Exclusion criteria /
Campillo[28] / 2013 / Spain / CC / Retrospective cohort study, comparing:
-  1st line treatment with STT vs. concomitant therapy.
-  The efficacy of re-treating those patients with LT. / NR / NR / Patients who had a positive UBT after concomitant or STT therapy 1st line regimen.
(Note: patients on STT arm were not included in this meta-analysis) / NR /
Cerqueira[29] / 2015 / Portugal / CC / Prospective cohort study, not comparative.
Investigates the efficacy of a treatment strategy in which patients received a 1st line concomitant therapy, and those failing to eradicate were retreated with LT regimen. / Adults / Obese Hp+ patients. / Obese Hp+ patients undergoing Roux-en Y gastric by-pass surgery who had an eradication failure with the concomitant 1st line therapy. / NR /
Chung[25] / 2014 / Korea / JA / Retrospective cohort study.
Compares the efficacy of MT vs. BQT in a cohort of patients from 2010 to 2013. / Adults / Ulcer, reflux disease / H. pylori-infected patients who failed 1st line H. pylori eradication treatment with SST, sequential or concomitant regimen
(Note: patients on STT arm were not included in this meta-analysis) / 1)  Age < 18 years.
2)  Previous gastric surgery.
3)  Serious comorbidity (e.g., decompensated liver cirrhosis, disseminated malignancy, and uremia).
4)  Patients who were treated with second-line regimens different from moxifloxacin-containing triple therapy or bismuth-containing quadruple therapy.
5)  Allergy to any of the drugs used in the study.
6)  Pregnancy. /
Georgopoulos[30] / 2013 / Greece / JA / Prospective cohort study, not comparative.
Investigates the efficacy of a 1st line concomitant therapy, and those patients failing that regimen were retreated with LT therapy. / Adults / Ulcer, dyspepsia, reflux disease, esophagitis. / Patients who had an eradication failure after the 1st line concomitant regimen. / NR /
Gisbert[22] / 2014 / Spain / CC/JA / Prospective cohort study, not comparative.
Investigates the efficacy of 2nd line LT therapy after the failure of the sequential or concomitant regimens. / Adults / Ulcer, dyspepsia / Consecutive patients for whom a first eradication trial with a non-bismuth quadruple regimen, administered either sequentially or concomitantly had previously failed. / 1)  Age < 18 years.
2)  Presence of clinically significant associated conditions.
3)  Previous gastric surgery.
4)  Allergy to any of drugs used in the study. /
Gisbert[36] / 2015 / Spain / JA / Prospective cohort study, not comparative.
Investigates the efficacy of 2nd line MT therapy after the failure of STT, sequential or concomitant regimens. / Adults / Ulcer, dyspepsia / Patients in whose 1st line therapy (STT or a non-bismuth quadruple therapy) had failed to eradicate H. pylori infection.
(Note: patients on STT arm were not included in this meta-analysis) / 1)  Age < 18 years.
2)  Presence of clinically significant associated conditions (insulin-dependent diabetes mellitus, neoplastic diseases, coagulation disorders, and hepatic, cardiorespiratory, or renal diseases).
3)  Previous gastric surgery.
4)  Allergy to any of the drugs used in the study. /
Gisbert[37] / 2015 / Spain / JA / Prospective cohort study, not comparative.
Investigates the efficacy of 2nd line LBQ therapy after the failure of a 1st line STT, sequential or concomitant regimens. / Adults / Ulcer, dyspepsia / Patients in whose 1st line therapy (STT or a non-bismuth quadruple therapy) had failed to eradicate H. pylori infection.
(Note: patients on STT arm were not included in this meta-analysis) / 1)  Age < 18 years.
2)  Presence of clinically significant associated conditions (insulin dependent diabetes mellitus, neoplastic diseases, coagulation disorders, and hepatic, cardiorespiratory or renal diseases).
3)  previous gastric surgery.
4)  Allergy to any of the drugs used in the study. /
Hsu[24] / 2014 / Taiwan / JA / Prospective cohort study, not comparative.
Evaluates the efficacy of 2nd line LBQ therapy after the failure of sequential regimen. / NR / Ulcer, dyspepsia / Patients with an eradication failure after the 1st line sequential regimen. / 1)  Previous gastric surgery.
2)  Coexistence of serious concomitant illness (e.g., decompensated liver cirrhosis, uremia). /
Kang[26] / 2014 / South Korea / JA / Retrospective cohort study.
Investigates the efficacy of 2nd line MT therapy of 7 and 14 days after the failure of 4 type of first-line treatments: SST, BQT, sequential and concomitant therapies. / Adults / Ulcer, dyspepsia / Patients for whom eradication of H. pylori infection was not successful following 1st line treatment and who subsequently received
MT as 2nd line treatment.
(Note: only patients receiving sequential or concomitant treatment as 1st line therapy were included in this meta-analysis). / 1)  Age < 18 years.
2)  Use of H2 receptor antagonists, PPIs, or antibiotics in the previous 4 wk, or use of NSAIDs or steroid in the 2 wk before the UBT.
3)  Previous gastric surgery or endoscopic mucosal dissection for gastric cancer.
4)  Advanced gastric cancer.
5)  Systemic illness, such as liver cirrhosis or chronic renal failure.
6)  Pregnancy.
7)  Insufficient data. /
Lim[27] / 2015 / South Korea / JA / Retrospective cohort study.
Investigates the efficacy of 2nd line MT therapy of 7 and 14 days after the failure of sequential or concomitant treatments. / Adults / Ulcer, dyspepsia / Patients who failed a 1st line non-bismuth quadruple therapy for H. pylori eradication between 2010-2012, and received a 2nd line MT therapy. / 1)  Age < 18 years.
2)  Use of H2 receptor antagonists, PPIs, or antibiotics in the previous 4 wk as well as the use of NSAIDs within 2 wk before the performance of the UBT.
3)  Previous gastric surgery.
4)  Advanced gastric cancer.
5)  Systemic illness such as liver cirrhosis or chronic renal failure.
6)  Pregnancy.
7)  Insufficient data. /
Liou[39] / 2013 / Taiwan / JA / Prospective randomized open-label study for 1st line therapy, allocating the patients to one of two therapies: Sequential or STT.
Patients failing one of these 1st line treatments received the MS therapy. / Adults / Ulcer, dyspepsia / Patients with an eradication failure after the 1st line regimen that was randomly assigned.
(Note: patients on STT arm were not included in this meta-analysis) / 1)  History of gastrectomy.
2)  Contraindication or previous allergic reactions to the study drugs.
3)  Pregnant or lactating women.
4)  Use of antibiotics within the previous 4 weeks.
5)  Severe concurrent diseases or malignancy. /
Manfredi[33] / 2012 / Italy / JA / Prospective cohort study, not comparative.
Investigates the efficacy of a treatment strategy in which patients received a 1st line sequential therapy, and those failing to eradicate were retreated with LT regimen. / Adults / Gastritis, ulcer / Adult patients with H. pylori infection after the failure of the 1st line sequential regime. / 1)  Concomitant use of anticoagulant drugs or ketoconazole and glucocorticoid drugs.
2)  Zollinger-Ellison Syndrome.
3)  Allergy to antibiotics.
4)  Previous surgical procedures of gastrointestinal tract (except polypectomy and cholecystectomy).
5)  Severe cardiovascular, endocrinologic, or lung diseases.
6)  Severe hepato-kidney dysfunctions.
7)  Hematologic disorders.
8)  Neoplastic diseases in 5 years previous to recruitment.
9)  Drugs or alcohol abuse in the last year.
10)  Neurologic or psychiatric pathologies.
11)  Pregnancy or breastfeeding or women active sexually that not use contraceptive device for all time of study. /
Perna[34] / 2007 / Italy / JA / Prospective cohort study, not comparative.
Investigates the efficacy of 2nd line LT treatment after failure of sequential or STT therapy. / Adults / Ulcer, dyspepsia / Patients failing a 1st line eradication therapy with sequential or STT therapy.
(Note: patients on standard treatment arm were not included in this meta-analysis) / 1)  Concomitant anticoagulant or ketoconazole.
2)  Zollinger-Ellison síndrome.
3)  Previous surgery of the esophagus and/or upper gastrointestinal tract (with the exception of appendectomy, polypectomy and cholecystectomy).
4)  Severe or unstable cardiovascular, pulmonary, or endocrine disease.
5)  Clinically significant renal or hepatic disease or dysfunction
6)  Hematological disorder.
7)  Malignant disease during the previous 5 years except for successfully treated skin (basal or squamous cell) cancer or Barrett esophagus with high grade dysplasia.
8)  Drug or medication abuse within the previous year.
9)  Severe psychiatric or neurological disorders.
10)  Pregnancy or breastfeeding or women active sexually that not use contraceptive device for all time of study. /
Pontone[35] / 2010 / Italy / JA / Prospective cohort study, not comparative.
Investigates the efficacy of a treatment strategy in which patients received a 1st line sequential therapy, and those failing to eradicate were retreated with LT regimen. / Adults / Ulcer, dyspepsia / Patients older than 18 years old and complaining of dyspeptic symptoms with a proven H. pylori infection. / 1)  Pregnant women.
2)  Patients with known antibiotic allergy.
3)  Neoplasia.
4)  Severe hepatic impairment or kidney failure. /
Zullo[32] / 2006 / Italy / JA / Prospective cohort study, not comparative.
Investigates the efficacy of 2nd line LT regimen after failure of sequential therapy. / NR / Ulcer, dyspepsia / Patients aged over 18 years, with persistent H. pylori infection after sequential therapy. / 1)  Allergies towards penicillin and/or quinolones.
2)  Pregnancy.
3)  Hepatic impairment or kidney failure. /
Zullo[31] / 2013 / Italy / JA / Prospective randomized open-label study for 1st line therapy, allocating the patients to one of three therapies: sequential, concomitant or hybrid therapy.
Patients failing one of those treatments received the 2nd line LT therapy. / Adults / Dyspepsia / Patients failing a 1st eradication attempt.
(Note: patients on hybrid treatment arm were not included in this meta-analysis) / 1)  Age < 18 years.
2)  Previous gastric surgery.
3)  Presence of either liver cirrhosis or kidney failure.
4)  Pregnancy.
5)  Known allergy to antibiotics.
6)  Patients with peptic ulcer as well as those with a documented history of peptic ulcer. /

CC: congress communication. JA: journal article. NR: not reported. Adults: over 18 years old. Hp+: H. pylori positive. LT: levofloxacin triple therapy. MT: moxifloxacin triple therapy. MS: modified sequential therapy. BQT: bismuth-containing quadruple therapy. UBT: 13C-Urea breath test. STT: standard triple therapy. PPI: proton pump inhibitors. NSAID: nonsteroidal anti-inflammatory drugs.

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