Table 1.
Main characteristics of the studies included in this meta-analysis
| Study | Country | Study design | SIBO diagnostic test | Prevalence of SIBO in Parkinson's patients | SIBO diagnostic criteria | Age (years) | Gender (male/female) | Disease course (years) | Quality assessment |
|---|---|---|---|---|---|---|---|---|---|
| Hasuike et al. [10], 2020 | Japan | cross‐sectional | LBT | 19/39(48.7%) | 10 g lactulose load is orally administered, H2 increase > 20 ppm above basal value within the first 2 h |
Overall 66.9 ± 10.4 SIBO + : 64.9 ± 6.3 SIBO-: 68.0 ± 5.4 |
Overall 17/22 SIBO + : 9/10 SIBO-: 7/9 |
Overall: 7.2 ± 5.1 SIBO + : 6.5 ± 2.0 SIBO-: 7.6 ± 2.5 |
Selection: 3 Comparability: 2 Outcome: 2 |
| DiBaise et al. [11], 2018 | USA | cross‐sectional | GBT | 12/51(23.5%) | not stated | not stated | 32/19 | not stated |
Selection: 3 Comparability: 2 Outcome: 2 |
| Su et al. [7], 2017 | USA | cross‐sectional | LBT | 22/64(34.4%) | 10 g lactulose load is orally administered, H2 increase > 20 ppm on 2 distinct peaks within 1.5 h | 72 (52–91) | 33/31 | 6.5 (0.6–22) |
Selection: 4 Comparability: 2 Outcome: 2 |
| Niu et al. [12], 2016 | China | cohort study | GBT | cases: 55/182(30.2%) controls:19/200(9.5%) | 50 g glucose load is orally administered, H2 increase > 20 ppm or CH4 increase > 10 ppm above basal value within the first 1 h | cases: 65 (50–74) SIBO + : 66 (50–75) SIBO-: 64 (50–74) controls: 65 (51–74) | cases: 104/78 SIBO + : 30/25 SIBO-: 74/53 controls: none | cases: 7 (3–12) SIBO + : 10 (5–15) SIBO-: 6 (2–10) |
Selection: 4 Comparability: 2 Outcome: 2 |
| Tan et al. [13], 2014 | Malaysia | cross‐sectional | LBT | 26/103 (25.2%) | 10 g lactulose load is orally administered, H2 increase > 10 ppm or CH4 increase > 20 ppm above basal value within the first 1.5 h |
Overall 65.4 ± 8.5 SIBO + : 67.2 ± 10.1 SIBO-: 64.8 ± 8.0 |
Overall 62/41 SIBO + : 16/10 SIBO-: 46/31 |
Overall 7.3 ± 5.3 SIBO + : 5.2 ± 4.1 SIBO-: 8.1 ± 5.5 |
Selection: 4 Comparability: 2 Outcome: 2 |
| Fasano et al. [14], 2013 | Italy | cohort study | LBT and GBT | cases: 18/33(54.5%) controls: 6/30 (20%) | not stated |
cases: 67.8 ± 8.5 controls: 65.4 ± 4.8 |
cases: 18/15 SIBO + : 11/7 SIBO-: 7/8 controls:13/17 |
cases: 11.7 ± 5.0 controls: none |
Selection: 3 Comparability: 2 Outcome: 3 |
| Dobbs et al. [15], 2013 | UK | cross-sectional | LBT | 40/66 (60.6%) | 25 g lactulose load is orally administered, H2 increase > 20 ppm on 2 consecutive measurements within 2 h | Overall 63 (46, 82) | Overall 41/25 |
Overall 6.8 (4.5, 8.7) |
Selection: 4 Comparability: 2 Outcome: 2 |
| Dobbs et al. [16], 2012 | UK | cross‐sectional | LBT | 34/51 (66.7%) | 25 g lactulose load is orally administered, H2 increase > 20 ppm on 2 consecutive measurements within 2 h | 65 (48,81) | 32/19 | 6.5 (4.4,8.9) |
Selection: 4 Comparability: 2 Outcome: 2 |
| Gabrielli et al. [17], 2011 | Germany | cohort study | GBT | cases: 26/48(54.2%) controls:3/36 (8.3%) | 50 g glucose load is orally administered, H2 increase > 12 ppm above basal value within 2 h |
cases: 66 ± 10 SIBO + : 67 ± 10 SIBO-: 63 ± 9 controls: 64 ± 9 |
cases: 23/25 SIBO + : 14/12 SIBO-: 9/13 controls:16/20 |
SIBO + : 10.6 ± 3.6 SIBO-: 7.4 ± 2.7 controls: none |
Selection: 4 Comparability: 2 Outcome: 2 |
| Charlett et al. [18], 2009 | UK | cross‐sectional | LBT | 24/40(60%) | 25 g lactulose load is orally administered, H2 increase > 20 ppm on 2 consecutive measurements within 2 h | 60.8 (41.0–80.5) | not stated | not stated |
Selection: 3 Comparability: 2 Outcome: 2 |
| Davies et al. [19], 1996 | UK | cohort study | LBT | cases:10/15(66.7%) controls:3/15(20%) | 10 g lactulose load is orally administered, a rise of at least 5 ppm above fasting levels in the end expiratory hydrogen concentration |
cases: 73.9 (68.3–80.5) controls: 73.6 (67.6–80.3) |
cases: 6/9 controls: 6/9 |
not stated |
Selection: 3 Comparability: 2 Outcome: 1 |
LHB lactulose breath test, GBT glucose breath test, ppm parts per million, SIBO small intestinal bacterial overgrowth