Table 2.

Studies investigating the association between periodontal disease and QOL in patients with COPD.

Author (Year)	Location	Study Design	Study Population	n	Measured Outcome	Main Findings
Zhou et al., 2011 [43]	China	Cross-sectional	Patients with COPD being treated at eight hospitals in Beijing	306	Periodontal parameters: PD, CAL, BOP, PI, and the number of missing teeth QOL measurement: SGRQ	The missing teeth were significantly associated with symptom score (p = 0.030) and activity score (p = 0.033); PI was also significantly associated with symptom score (p = 0.007).
Baldomero et al., 2019 [44]	USA	Case-control (exacerbators vs. non-exacerbators)	Individuals from the Minneapolis Veterans Affairs health care system	136 (patients with COPD: exacerbator, n = 70; non-exacerbator, n = 66)	Periodontal parameters: OHIP-5; PD, CAL, BOP, GI, PI, and caries risk assessment (subset of patients) QOL measurement: SGRQ	Worse OHRQoL as measured by OHIP-5 was associated with worse respiratory health scores (SGRQ total score): difficulty chewing (regression coefficient, 2.57; p = 0.023), painful ache in the mouth (regression coefficient, 5.43; p < 0.001), uncomfortable about appearance (regression coefficient, 3.17; p = 0.003), less flavor (regression coefficient, 3.53; p = 0.005), and difficulty performing jobs (regression coefficient, 7.31; p < 0.001).
Gaeckle et al., 2018 [45]	USA	Prospective cohort	Healthy individuals without lung disease and patients with severe COPD, recruited at a single medical center	30 (case, n = 20; control, n = 10)	Periodontal parameters: PI and OHIP-14 QOL measurement: electronic COPD daily diary	In patients with COPD, the number of teeth showed a significant positive correlation with the percentage of days with cough (β = 2.70, p = 0.04) and wheezing (β = 2.65, p = 0.01), whereas PI showed no significant correlation with daily respiratory symptoms.
Agado et al., 2012 [46]	USA	Randomized controlled trial	Patients diagnosed with COPD and chronic periodontitis	30 (magnetostrictive ultrasonic instrument, n = 10; hand instrument, n = 10; control, n = 10)	Periodontal parameters: PI and CAL QOL measurements: SGRQ-A and illness questionnaire (developed by the principal investigator)	SGRQ-A (symptom, p = 0.124; activity, p = 0.702; impact, p = 0.926) and illness questionnaire scores did not demonstrate significant differences in QOL or illness after periodontal debridement between groups.

BOP, bleeding on probing; CAL, clinical attachment loss; COPD, chronic obstructive pulmonary disease; GI, gingival index; OHIP, Oral Health Impact Profile; OHRQoL, oral health-related quality of life; PD, probing depth; PI, plaque index; QOL, quality of life; SGRQ, St. George’s Respiratory Questionnaire.