Table 2.
Results of subgroup analysis and meta-regression
| Subgroup analysis (heterogeneity explained and p valuea) | Category | NOC | Pooled results | Heterogeneity | ||
|---|---|---|---|---|---|---|
| WMD (95% CI) | p value | I2 | p value | |||
| 3-month follow-up | ||||||
| Total | – | 20 | − 0.514 (− 0.730, − 0.298) | 0.000 | 88.0% | 0.000 |
| Baseline HbA1c (%) (90.95%; p = 0.000) | < 8 | 12 | − 0.178 (− 0.267, − 0.090) | 0.000 | 15.5% | 0.292 |
| 8–9 | 3 | − 0.929 (− 1.278, − 0.581) | 0.000 | 45.1% | 0.162 | |
| ≥ 9 | 5 | − 1.179 (− 1.379, − 0.979) | 0.000 | 0.0% | 0.572 | |
| Baseline PPD (mm) (10.47%; p = 0.219) | < 3 | 9 | − 0.266 (− 0.440, − 0.092) | 0.003 | 36.8% | 0.124 |
| 3–4 | 5 | − 0.510 (− 1.129, 0.110) | 0.107 | 93.5% | 0.000 | |
| ≥ 4 | 6 | − 0.755 (− 1.139, − 0.371) | 0.000 | 87.7% | 0.000 | |
| Reduction of PPD after periodontal therapy (mm) (35.29%; p = 0.015) | < 0.5 | 8 | − 0.312 (− 0.560, − 0.064) | 0.014 | 64.5% | 0.006 |
| 0.5–1 | 9 | − 0.475 (− 0.814, − 0.137) | 0.006 | 92.1% | 0.000 | |
| ≥ 1 | 3 | − 1.120 (− 1.404, − 0.836) | 0.000 | 0.0% | 0.933 | |
| Jadad score (− 4.99%; p = 0.696) | ≥ 4 | 9 | − 0.471 (− 0.835, − 0.107) | 0.011 | 90.5% | 0.000 |
| < 4 | 11 | − 0.554 (− 0.843, − 0.264) | 0.000 | 85.9% | 0.000 | |
| Sample size (14.04%; p = 0.091) | ≥ 100 | 3 | 0.008 (− 0.158, 0.175) | 0.922 | 0.0% | 0.653 |
| < 100 | 17 | − 0.584 (− 0.816, − 0.351) | 0.000 | 87.8% | 0.000 | |
| ΔHbA1c as outcome (0.06%; p = 0.325) | Yes | 9 | − 0.415 (− 0.700, − 0.131) | 0.004 | 93.4% | 0.000 |
| No | 11 | − 0.640 (− 0.946, − 0.334) | 0.000 | 56.0% | 0.012 | |
| Treatment group received periodontal surgery or tooth extraction (− 6.37%; p = 0.738) | Yes | 5 | − 0.499 (− 0.759, − 0.239) | 0.000 | 0.0% | 0.693 |
| No | 15 | − 0.497 (− 0.746, − 0.249) | 0.000 | 91.0% | 0.000 | |
| Treatment group received antibiotics (20.09%; p = 0.106) | Yes | 3 | − 0.956 (− 1.205, − 0.707) | 0.000 | 42.1% | 0.178 |
| No | 17 | − 0.420 (− 0.620, − 0.221) | 0.000 | 80.9% | 0.000 | |
| Control group received supragingival scaling or tooth extraction (− 6.04%; p = 0.877) | Yes | 3 | − 0.509 (− 0.894, − 0.124) | 0.010 | 0.0% | 0.812 |
| No | 17 | − 0.522 (− 0.756, − 0.287) | 0.000 | 89.8% | 0.000 | |
| Reported no significant change in T2DM treatment during trial (− 7.28%; p = 0.914) | Yes | 15 | − 0.508 (− 0.759, − 0.256) | 0.000 | 86.9% | 0.000 |
| No | 5 | − 0.538 (− 0.988, − 0.087) | 0.019 | 88.2% | 0.000 | |
| Published in Chinese (1.89%; p = 0.383) | Yes | 4 | − 0.708 (− 1.241, − 0.176) | 0.000 | 72.8% | 0.000 |
| No | 16 | − 0.464 (− 0.697, − 0.231) | 0.009 | 88.7% | 0.012 | |
| 6-month follow-up | ||||||
| Total | – | 11 | − 0.548 (− 0.859, − 0.238) | 0.000 | 88.1% | 0.000 |
| Baseline HbA1c (%) (80.90%; p = 0.001) (85.62%; p = 0.002)b | < 8 | 7 | − 0.205 (− 0.389, − 0.021) | 0.029 | 41.5% | 0.114 |
| 8–9 | 1 | − 0.600 (− 0.900, − 0.300) | 0.000 | – | – | |
| ≥ 9 | 3 | − 1.199 (− 1.675, − 0.723) | 0.000 | 80.3% | 0.006 | |
| ≥ 9b | 2 | − 0.953 (− 1.200, − 0.706) | 0.000 | 0.0% | 0.906 | |
| Baseline PPD (mm) (11.67%; p = 0.172) | < 3 | 4 | − 0.309 (− 0.490, − 0.128) | 0.001 | 0.0% | 0.982 |
| 3–4 | 5 | − 0.560 (− 1.143, 0.023) | 0.060 | 93.9% | 0.000 | |
| ≥ 4 | 2 | − 0.953 (− 1.200, − 0.706) | 0.000 | 0.0% | 0.906 | |
| Reduction of PPD after periodontal therapy (mm) (27.88%; p = 0.075) | < 0.5 | 4 | − 0.034 (− 0.222, 0.154) | 0.722 | 0.0% | 0.399 |
| 0.5–1 | 5 | − 0.634 (− 1.119, − 0.149) | 0.010 | 91.3% | 0.000 | |
| ≥ 1 | 2 | − 0.953 (− 1.200, − 0.706) | 0.000 | 0.0% | 0.906 | |
| Jadad score (11.44%; p = 0.168) | ≥ 4 | 6 | − 0.323 (− 0.623, − 0.023) | 0.035 | 66.9% | 0.010 |
| < 4 | 5 | − 0.786 (− 1.315, − 0.257) | 0.004 | 92.8% | 0.000 | |
| Sample size (− 8.78%; p = 0.621) | ≥ 100 | 4 | − 0.440 (− 0.943, 0.062) | 0.086 | 89.5% | 0.000 |
| < 100 | 7 | − 0.613 (− 1.047, − 0.178) | 0.006 | 88.5% | 0.000 | |
| ΔHbA1c as outcome (− 10.10%; p = 0.746) | Yes | 4 | − 0.487 (− 1.107, 0.133) | 0.124 | 36.2% | 0.152 |
| No | 7 | − 0.653 (− 0.861, − 0.445) | 0.000 | 95.1% | 0.000 | |
| Treatment group received periodontal surgery or tooth extraction (− 13.38%; p = 0.920) | Yes | 1 | − 0.600 (− 0.900, − 0.300) | 0.000 | – | – |
| No | 10 | − 0.542 (− 0.890, − 0.195) | 0.002 | 89.3% | 0.000 | |
| Treatment group received antibiotics (− 12.83%; p = 0.886) | Yes | 2 | − 0.497 (− 1.369, 0.375) | 0.002 | 92.5% | 0.000 |
| No | 9 | − 0.560 (− 0.917, − 0.203) | 0.264 | 88.8% | 0.000 | |
| Control group received supragingival scaling or tooth extraction (− 11.89%; p = 0.809) | Yes | 3 | − 0.548 (− 0.782, − 0.314) | 0.006 | 91.6% | 0.000 |
| No | 8 | − 0.573 (− 0.979, − 0.167) | 0.000 | 0.0% | 0.640 | |
| Reported no significant change in T2DM treatment during trial (− 8.19%; p = 0.642) | Yes | 10 | − 0.571 (− 0.901, − 0.241) | 0.001 | 89.4% | 0.000 |
| No | 1 | − 0.280 (− 0.869, 0.309) | 0.351 | – | – | |
| Published in Chinese (− 2.68%; p = 0.445) | Yes | 3 | − 0.471 (− 0.840, − 0.101) | 0.013 | 53.3% | 0.118 |
| No | 8 | − 0.801 (− 1.152, − 0.450) | 0.000 | 89.4% | 0.000 | |
CI Confidence inteval, NOC number of comparisons, WMD weighted mean difference
aCalculated by single variable meta-regression
bCalculated after deleting Kaur et al.’s [22] study