Table 2.

Results summary for the primary outcome COPD exacerbation frequency

Study	Outcome and how measured	Results summary
Liu et al. [34]	Self-reported COPD exacerbations/change in clinical symptoms and medication	CAL, PPD and BI were not associated with exacerbations. However, fewer remaining teeth [OR = 1.69, 95%CI 1.03–2.77, p = 0.04], and low tooth brushing times [OR = 4.19, 95% CI 1.44–12.1, p = 0.008] were significantly associated with exacerbations after adjusting for age, gender, smoking, body mass index, COPD severity and dyspnoea scores
Kucukcoskun et al. [39]	COPD exacerbations, confirmed by chest physician	Periodontal treatment result in significant reduction in GI (p = 0.002), PPD (p = 0.003), CAL (p = 0.001), and BOP (p = 0.002) at month 6. At 12 month follow up, exacerbation frequency was significantly reduced in those who received periodontal treatment (p = 0.01). Sex, age, FEV1, FVC, COPD severity, number of previous exacerbations, and PPD > 4 mm did not affect exacerbation frequency
Zhou et al. [38]	Self-reported COPD exacerbations/ change in clinical symptoms and medication/spirometry	At the 2-year follow up, periodontal treatment groups had a lower proportion of frequent exacerbations (SRP 30%, supra-gingival scaling 15.8%) compared with the control group (66.7%) and the difference was statistically significant (p = 0.004). After adjusting for age, gender body mass index, smoking status, and baseline frequent exacerbations the ORs for frequent COPD exacerbation were 0.29 (95% CI 0.10–0.84) for the SRP group and 0.04 (95% CI 0.003–0.64) for the scaling group
AbdelHalim et al. [35]	Self-reported COPD exacerbations and spirometry measurements	Frequent exacerbations were associated with high PI scores (p = 0.029), high BI (p = 0.04), high GI (p < 0.001), moderate to severe clinical attachment loss (CAL) and probing pocket depth (PPD) (p < 0.001). GI appeared to be the most important predictor of exacerbations (P < 0.001) followed by PI (P = 0.05). Adjusting for demographics, clinical parameters, C–reactive protein level and spirometry data only PI (p = 0.003) and BI (p = 0.04) remained significantly associated with exacerbations
Baldomero et al. [36]	Self-reported COPD exacerbations verified by medical chart review	The unadjusted and adjusted odds ratio for self-reported oral health status and dental exam measures did not vary significantly between exacerbators and non-exacerbators. There was a trend towards higher odds of exacerbations in those with “dry mouth” in both unadjusted [OR 2.18; 95% CI 1.09–4.43, p = 0.03] and adjusted [OR 2.29; 95% CI 0.99–5.44, p = 0.05] models