Karbasi 2013.

Methods	Aim of study: to determine the efficacy of NAC on eradication of H pylori infections in participants suffering from dyspepsia. Study design: randomised controlled study. Study grouping: parallel group. Unit of allocation: by individuals. Country: Iran. Start date: not reported. End date: not reported. Duration of participation: 6 weeks. Ethical approval: approved by the ethical committee of the Tehran Islamic Azad Medical University.
Participants	Total number randomised: 60. Method of recruitment: not reported. Informed consent obtained: informed written consent, approved by the ethical committee of the Tehran Islamic Azad Medical University, was obtained from all participants before their participation in the study. Baseline imbalances: the participants were matched for age and sex. Information about other types of imbalances was not available. Withdrawals and exclusions: two participants dropped out from the placebo group for unknown reasons. Subgroups measured: endoscopic findings, age, gender. Subgroups reported: endoscopic findings, age, gender. Mean age: 41.5 ± 13.53 years, range 17 to 76 years overall. Not reported in details about group A or group B. Gender (M/F): group A (14/16), group B ( 14/14). Race/ethnicity: not reported. Severity of condition: dyspepsia. Normal oesophagus, non‐ulcerative oesophagitis, erosive oesophagitis, normal stomach, antral gastritis, pangastritis, erosive gastritis, normal duodenum, erosive duodenitis, duodenitis and duodenal ulcer were observed. Comorbidities: not reported. Diagnostic criteria: diagnosis of positive infection with H pylori was performed on the basis of endoscopic examination and H pylori rapid urease test. Setting: not reported. Inclusion criteria: history of chronic dyspepsia at least for three months, diagnosis of H pylori infection, no participation in clinical studies or not being under treatment with other drugs. Exclusion criteria: withdrawal, severe and debilitating underlying disease, recent consumption of antibiotics, bismuth, NSAID drugs, corticosteroids during the past one month, pregnancy or lactation, and a positive history of surgery or gastric cancer.
Interventions	Number randomised in each group: group A (n = 30) , group B (n = 28). Dose Group A: consisted of three drugs including pantoprazole 40 mg twice a day, ciprofloxacin 500 mg twice a day and bismuth subcitrate 120 mg two tablets twice a day, plus 600 mg NAC twice a day. Group B: consisted of three drugs including pantoprazole 40 mg twice a day, ciprofloxacin 500 mg twice a day and bismuth subcitrate 120 mg two tablets twice a day, plus placebo 600 mg twice a day. Duration of treatment period: 14 days. Timing: as described above. Delivery: oral. Providers: not reported. Cointerventions: none. Economic information: not reported. Resource requirements: not reported. Integrity of delivery: not reported. Compliance: not reported.
Outcomes	Primary outcomes: eradication rates, defined as the number of participants with negative urea breath test after treatment. Secondary outcomes: none. Time points measured and reported: four weeks after treatment. Person measuring/reporting: a gastroenterologist. Unit of measurement: ‐ Scales: ‐ Imputation of missing data: not reported. Assumed risk estimates: not reported. Power: not reported.
Notes	Publication status: full text. Funding source: not declared. Conflict of interest: authors declared no conflicts. Contact with authors: we contacted the authors on 26 January 2017 but received no reply.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "In this randomized double‐blinded placebo‐control study 60 patients were enrolled." Comment: insufficient information to allow judgement.
Allocation concealment (selection bias)	Unclear risk	Comment: insufficient information to allow judgement.
Blinding of participants and personnel (performance bias) Eradication (frequency)	Low risk	Comment: the method used for assessment of eradication was an objective test, unlikely to be influenced by blinding.
Blinding of participants and personnel (performance bias) Gastrintestinal adverse events	Unclear risk	Comment: the study did not address this outcome.
Blinding of participants and personnel (performance bias) Allergic adverse events	Unclear risk	Comment: the study did not address this outcome.
Blinding of participants and personnel (performance bias) Toxic adverse events	Unclear risk	Comment: the study did not address this outcome.
Blinding of outcome assessment (detection bias) Eradication (frequency)	Low risk	Comment: the method used for assessment of eradication was an objective test, unlikely to be influenced by blinding of assessor.
Blinding of outcome assessment (detection bias) Gastrintestinal adverse events	Unclear risk	Comment: the study did not address this outcome.
Blinding of outcome assessment (detection bias) Allergic adverse events	Unclear risk	Comment: the study did not address this outcome.
Blinding of outcome assessment (detection bias) Toxic adverse events	Unclear risk	Comment: the study did not address this outcome.
Incomplete outcome data (attrition bias) Eradication (frequency)	Low risk	Comment: there was a loss of 6% (2/30) in the control group. Participants dropped out because of unknown reasons. It is unlikely that this fact could influence the results.
Incomplete outcome data (attrition bias) Gastrintestinal adverse events	Low risk	Comment: there was a loss of 6% (2/30) in the control group. Participants dropped out because of unknown reasons. It is unlikely that this fact could influence the results.
Incomplete outcome data (attrition bias) Allergic adverse events	Low risk	Comment: there was a loss of 6% (2/30) in the control group. Participants dropped out because of unknown reasons. It is unlikely that this fact could influence the results.
Incomplete outcome data (attrition bias) Toxic adverse events	Low risk	Comment: there was a loss of 6% (2/30) in the control group. Participants dropped out because of unknown reasons. It is unlikely that this fact could influence the results.
Selective reporting (reporting bias)	Low risk	All outcomes that are of interest in this review were presented.
Other bias	Low risk	This study seems to be free of other sources of bias.