Periodontal Status and Microbiologic Pathogens in Patients with Chronic Obstructive Pulmonary Disease and Periodontitis: A Case-Control Study

Purpose: To evaluate clinical periodontal status and microbiologic pathogens in patients with chronic obstructive pulmonary disease (COPD) and periodontitis. Patients and Methods: We conducted a case-control study of 60 periodontitis patients with COPD (case group) and 60 periodontitis patients with normal pulmonary function (control group). Their periodontal status and respiratory function were clinically examined. Real-time polymerase chain reaction assays were used to measure five dental pathogens and four respiratory pathogens in subgingival dental plaque. Spearman's rank correlation coefficients (r(2)) were calculated to assess correlations of pathogens. Principal component analysis (PCA) was employed to assess the similarity of bacterial diversity between the two groups. Logistic regression was performed to examine the associations of periodontal variables and pathogens with COPD risk. Results: COPD patients had fewer remaining teeth, higher plaque index (PLI), and more severe site percentages of clinical attachment level (CAL) than the controls. Although COPD patients tended to have relatively higher ranked means of Porphyromonas gingivalis, Tannerella forsythensis, Treponema denticola, and Haemophilus influenza than control participants, the differences were not significant. Some periodontal pathogens and respiratory pathogens were positively correlated with each other (r(2) =0.29 to 0.47, all P < 0.05). The PCA graph showed that the distributions of pathogens were more dispersed but less discriminated in the COPD group than those in the control group. PLI (P = 0.045) and CAL >= 5mm site percentages (P = 0.01) were significantly associated with an increased risk of COPD, while pathogens were not associated with COPD. Conclusion: Our results from this study do not indicate periodontal pathogens as potential predictors of COPD risk, despite significantly poor periodontal status associated with COPD.