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) |
|||
| Dual therapies | ||||||
| 702 per 1000 | 435 per 1000 (295 to 632) |
RR 0.62 (0.42 to 0.90) |
92 (2 RCTs) |
|||
| Sequential therapy | ||||||
| 420 per 1000 | 328 per 1000 (193 to 546) |
RR 0.78 (0.46 to 1.30) |
99 (1 RCT) |
|||
| Bismuth quadruple therapy | ||||||
| 183 per 1000 | 180 per 1000 (84 to 383) |
RR 0.98 (0.46 to 2.09) |
121 (1 RCT) |
|||
| No PPI, antibiotic monotherapy | ||||||
| 400 per 1000 | 456 per 1000 (264 to 788) |
RR 1.14 (0.66 to 1.97) |
70 (1 RCT) |
|||
|
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) |
|||
| Dual therapies | ||||||
| 0 per 1000 | 0 per 1000 | not estimable | 92 (2 RCTs) |
|||
| Sequential therapy | ||||||
| 262 per 1000 | 267 per 1000 (131 to 550) |
RR 1.02 (0.50 to 2.10) |
83 (1 RCT) |
|||
| Bismuth quadruple therapy | ||||||
| 250 per 1000 | 345 per 1000 (198 to 603) |
RR 1.38 (0.79 to 2.41) |
121 (1 RCT) |
|||
| 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) |
|||
| Dual therapies | ||||||
| 0 per 1000 | 0 per 1000 | RR 3.00 (0.13 to 68.84) |
92 (2 RCTs) |
|||
| 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) |
|||
| 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) |
|||
| Dual Therapies | ||||||
| 0 per 1000 | 0 per 1000 | not estimable | 92 (2 RCTs) |
|||
| Sequential therapy | ||||||
| 0 per 1000 | 0 per 1000 | not estimable | 83 (1 RCT) |
|||
| Bismuth quadruple therapy | ||||||
| 0 per 1000 | 0 per 1000 | not estimable | 121 (1 RCT) |
|||
| 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)).