Summary of findings for the main comparison. Any antibiotic regimen plus N‐acetylcysteine compared to the same regimen without N‐acetylcysteine (with or without placebo) for Helicobacter pylori infection.
Any antibiotic regimen plus NAC compared to the same regimen without NAC (with or without placebo) for H pylori infection | ||||||
Patient or population: people withH pylori infection Setting: outpatients Intervention: any antibiotic regimen plus NAC Comparison: the same antibiotic regimen (with or without placebo) | ||||||
Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | № of participants (studies) | Certainty of the evidence (GRADE) | Comments | |
Risk with any antibiotic regimen without NAC | Risk with any antibiotic regimen plus NAC | |||||
Eradication rate Follow‐up: 38 to 175 days |
Study population | RR 0.74 (0.51 to 1.08) | 559 (8 RCTs) | ⊕⊝⊝⊝ VERY LOW1 2 3 | ||
491 per 1000 | 363 per 1000 (250 to 530) | |||||
Triple therapies | ||||||
483 per 1000 | 300 per 1000 (203 to 440) |
RR 0.62 (0.42 to 0.91) |
177 (3 RCTs) |
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Dual therapies | ||||||
702 per 1000 | 435 per 1000 (295 to 632) |
RR 0.62 (0.42 to 0.90) |
92 (2 RCTs) |
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Sequential therapy | ||||||
420 per 1000 | 328 per 1000 (193 to 546) |
RR 0.78 (0.46 to 1.30) |
99 (1 RCT) |
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Bismuth quadruple therapy | ||||||
183 per 1000 | 180 per 1000 (84 to 383) |
RR 0.98 (0.46 to 2.09) |
121 (1 RCT) |
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No PPI, antibiotic monotherapy | ||||||
400 per 1000 | 456 per 1000 (264 to 788) |
RR 1.14 (0.66 to 1.97) |
70 (1 RCT) |
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Gastrointestinal adverse events Follow‐up: 38 to 175 days |
Study population | RR 1.25 (0.85 to 1.85) | 336 (5 RCTs) | ⊕⊝⊝⊝ VERY LOW3 4 | ||
189 per 1000 | 237 per 1000 (161 to 350) | |||||
Triple therapies | ||||||
300 per 1000 | 399 per 1000 (171 to 942) |
RR 1.33 (0.57 to 3.14) |
40 (1RCT) |
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Dual therapies | ||||||
0 per 1000 | 0 per 1000 | not estimable | 92 (2 RCTs) |
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Sequential therapy | ||||||
262 per 1000 | 267 per 1000 (131 to 550) |
RR 1.02 (0.50 to 2.10) |
83 (1 RCT) |
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Bismuth quadruple therapy | ||||||
250 per 1000 | 345 per 1000 (198 to 603) |
RR 1.38 (0.79 to 2.41) |
121 (1 RCT) |
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No PPI, antibiotic monotherapy | ||||||
Not measured | ||||||
Allergic adverse events Follow‐up: 38 to 175 days |
Study population | RR 2.98 (0.32 to 27.74) | 336 (5 RCTs) | ⊕⊝⊝⊝ VERY LOW3 4 | ||
0 per 1000 | 0 per 1000 (0 to 0) | |||||
Triple therapies | ||||||
0 per 1000 | 0 per 1000 | not estimable | 40 (1 RCT) |
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Dual therapies | ||||||
0 per 1000 | 0 per 1000 | RR 3.00 (0.13 to 68.84) |
92 (2 RCTs) |
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Sequential therapy | ||||||
0 per 1000 | 0 per 1000 | not estimable | 83 (1 RCT) |
No events in either group | ||
Bismuth quadruple therapy | ||||||
0 per 1000 | 0 per 1000 (0 to 0) |
RR 2.95 (0.12 to 71.05) |
121 (1RCT) |
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No PPI, antibiotic monotherapy | ||||||
Not measured | ||||||
Toxic adverse events Follow‐up: 38 to 175 days |
Study population | not estimable | 336 (5 RCTs) | ⊕⊕⊝⊝ LOW3 | No events in either group | |
0 per 1000 | 0 per 1000 (0 to 0) | |||||
Triple therapies | ||||||
0 per 1000 | 0 per 1000 | not estimable | 40 (1 RCT) |
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Dual Therapies | ||||||
0 per 1000 | 0 per 1000 | not estimable | 92 (2 RCTs) |
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Sequential therapy | ||||||
0 per 1000 | 0 per 1000 | not estimable | 83 (1 RCT) |
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Bismuth quadruple therapy | ||||||
0 per 1000 | 0 per 1000 | not estimable | 121 (1 RCT) |
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No PPI, antibiotic monotherapy | ||||||
Not measured | ||||||
*The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: Confidence interval; PPI: proton pump inhibitor; NAC: N‐acetylcysteine; RR: Risk ratio; OR: Odds ratio | ||||||
GRADE Working Group grades of evidence High certainty: We are very confident that the true effect lies close to that of the estimate of the effect Moderate certainty: We are moderately confident in the effect estimate: The true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different Low certainty: Our confidence in the effect estimate is limited: The true effect may be substantially different from the estimate of the effect Very low certainty: We have very little confidence in the effect estimate: The true effect is likely to be substantially different from the estimate of effect |
1 We downgraded by one level due to risk of bias (lack of information on sequence generation and allocation concealment).
2 We downgraded by one level due to imprecision (the confidence interval includes both null effect and appreciable benefit (RR 0.75)).
3 We downgraded by two levels due to inconsistency (large variation of effect, confidence intervals do not overlap, I2 > 50% and P < 0.05).
4 We downgraded by two levels due to risk of bias (lack of blinding of participants, personnel, and outcome assessors).
5 We downgraded by two levels due to imprecision (wide confidence interval that includes appreciable harm (RR 1.25)).