Table 3:
Certainty of Evidence
| Outcome | N/n | Estimate (95% CI) | Certainty of Evidence | Risk of Bias | Inconsistency | Imprecision | Indirectness | |
|---|---|---|---|---|---|---|---|---|
| Prevalence of GIM in the US | 6/897,731 | 4.8% (4.8 – 4.9) | ⊕⊕⊕○ Moderate |
Serious | Not serious1 | Not serious | Not serious | |
| Prevalence of GIM in the different regions | South Asia | 5/4,534 | 9.5% (8.7 – 10.4) | ⊕⊕○○ Low |
Serious | Serious | Not serious | Not serious |
| West Asia | 7/12,496 | 14.1% (13.5 – 14.7) |
⊕⊕○○ Low |
Serious | Serious | Not serious | Not serious | |
| North America | 6/897,731 | 4.8% (4.8 – 4.9) |
⊕⊕⊕○ Moderate |
Serious | Not serious1 | Not serious | Not serious | |
| South Europe | 3/2,652 | 17.5% (16.0 – 18.9) |
⊕⊕○○ Low |
Serious | Serious | Not serious | Not serious | |
| East Asia | 16/97,940 | 21.0% (20.7 – 21.2) |
⊕⊕○○ Low |
Serious | Serious2 | Not serious | Not serious | |
| South America | 2/3,919 | 23.9% (22.6 – 25.3) |
⊕⊕⊕○ Moderate |
Serious | Not serious | Not serious | Not serious | |
| West Europe | 2/916 | 16.6% (14.2 – 19.1) |
⊕○○○ Very low |
Serious3 | Serious | Serious4 | Not serious | |
| South-East Asia | 2/3,250 | 6.5% (5.7 – 7.4) |
⊕⊕○○ Low |
Serious | Serious | Not serious | Not serious | |
| North Europe | 6/346,215 | 3.4% (3.3 – 3.5) |
⊕⊕○○ Low |
Serious | Serious | Not serious | Not serious | |
| East Europe | 3/4,732 | 18.7% (17.6 – 19.8) |
⊕⊕○○ Low |
Serious | Serious | Not serious | Not serious | |
| Australia | 1/268 | 16.0% (11.9 – 20.7) |
⊕○○○ Very low |
Serious | Not serious | Very serious5 | Not serious | |
| Prevalence of GIM based on cagA status | cagA positive | 3/1,347 | 36.4% (33.8 – 39.0) |
⊕○○○ Very low |
Very serious6,7 | Serious | Serious | Serious |
| cagA negative | 2/1,002 | 21.3% (18.8 – 24.0) |
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| Uninfected | 2/719 | 17.8% (15.1 – 20.7) |
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| Prevalence of GIM in the US based on race/ethnicity7 | Non-Hispanic Black | 2/566 | 15.9% (13.0 – 19.0) |
⊕⊕○○ Low |
Serious8 | Not serious | Serious4 | Not serious |
| Hispanic | 2/220 | 23.3% (17.8 – 29.1) |
⊕○○○ Very low |
Serious8 | Serious | Very serious5 | Not serious | |
| Non-Hispanic White | 3/610 | 12.2% (9.7 – 15.0) |
⊕⊕○○ Low |
Serious8 | Not serious | Serious4 | Not serious | |
| Asian | 1/27 | 14.8% (3.5 – 31.1) |
⊕○○○ Very low |
Serious8 | Not serious | Very serious5 | Not serious | |
| Native American | 1/11 | 18.2% (0.5 – 47.4) |
⊕○○○ Very low |
Serious8 | Not serious | Very serious5 | Not serious | |
| Relative risk of finding GIM on gastric biopsies in patients on high vs. low salt diet | 2/4,890 | 1.18 (0.99 – 1.40) |
⊕○○○ Very low |
Very serious9 | Not serious | Not serious | Serious | |
| Relative risk of finding GIM on gastric biopsies in patients on low vs. high fruits/vegetables diet | 2/2,174 | 1.42 (1.13 – 1.79) |
⊕○○○ Very low |
Very serious9 | Not serious | Not serious | Serious | |
| Relative risk of finding GIM on gastric biopsies in patients with high vs. low dairy products intake | 1/4,931 | 1.72 (1.43 – 2.05) |
⊕○○○ Very low |
Very serious9 | Not serious | Not serious | Serious | |
| Prevalence of GIM in patients with pernicious anemia | 1/27 | 88.9% (70.8 – 97.6) |
⊕○○○ Very low |
Serious10 | Not serious | Very serious5 | Not serious | |
| Relative risk of finding GIM on gastric biopsies in patients with first-degree family history of gastric cancer vs. patients with no family history | 5/4,791 | 1.46 (0.97 – 2.21) |
⊕○○○ Very low |
Serious | Not serious | Serious | Serious | |
| Relative risk of finding GIM on gastric biopsies in patients who smoke tobacco versus non-smokers | 7/7,971 | 1.57 (1.24 – 1.98) |
⊕○○○ Very low |
Very serious9,11 | Not serious | Not serious | Serious | |
| Relative risk of finding GIM on gastric biopsies in patients who drink alcohol versus patients who did not drink alcohol | 6/6,775 | 1.29 (1.12 – 1.50) |
⊕○○○ Very low |
Very serious9,11 | Not serious | Not serious | Serious | |
| Prevalence of incomplete GIM in patients with GIM found during gastric biopsies | 13/2,742 | 47.7% (45.8 – 49.6) |
⊕○○○ Very low |
Serious | Very serious12 | Not serious | Serious | |
| Prevalence of extensive GIM in patients with GIM found during gastric biopsies | 9/3,558 | 30.3% (28.8 – 31.8) |
⊕○○○ Very low |
Serious | Serious13 | Not serious | Serious | |
the observed inconsistency was explained by the differences in the risk of bias between the individual studies.
the observed inconsistency was partially explained by the differences in the risk of bias between the individual studies.
the study by den Hod et al was well conducted with low risk of bias and we have higher certainty in its estimate (7%, 95% CI 5 – 10%) compared to the pooled estimate.
due to small total number of included patients.
due to very small total number of included patients.
the method of diagnosing H. pylori and cagA status differed between the studies.
the comparison between the subgroups is based on a Chi squared test which has inherent methodological limitations.
the studies did not report obtaining biopsies routinely from both antrum and corpus.
the relative risk estimate were not adjusted for other possible risk factors, that may contribute to risk of bias as in Appendix 2.
it was not clear how the subgroup of patients with pernicious anemia was identified.
the definition of exposure to smoking or alcohol was not clear in most of the studies (current use vs. prior use vs. never).
the observed inconsistency was not explained by differences in risk of bias or geographical region
the observed inconsistency was partially explained by the prevalence of H. pylori infection
Acronyms: N, number of studies; n, total number of patients; CI, confidence interval; GIM, gastric intestinal metaplasia; H. pylori, helicobacter pylori