Periodontitis as the risk factor of chronic kidney disease: Mediation analysis

To determine sequences and magnitude of causality among periodontitis, diabetes and chronic kidney disease (CKD) by mediation analysis.

Ten-year-data were retrieved from the Electric Generation Authority of Thailand (EGAT) study. A cohort of 2,635 subjects was identified with no CKD at baseline. The interested outcome was CKD incidence defined as glomerular filtration rate <60 ml/min/1.73 m² . The percentage of proximal sites with clinical attachment loss ≥5 mm was used to represent periodontitis. Mediation analysis with 1,000-replication bootstrapping was applied to two causal diagrams, diagram A (Periodontitis → Diabetes → CKD) and diagram B (Diabetes → Periodontitis → CKD).

The cumulative incidence of CKD was 10.3 cases per 100 persons during 10-year period. In diagram A, each increasing percentage of proximal sites with severe periodontitis increased the adjusted odds ratio of CKD 1.010 (95% CI: 1.005, 1.015) and 1.007 (95% CI: 1.004, 1.013), by direct and indirect effect through diabetes, respectively. In diagram B, diabetes increased the odds of CKD twofold, with 6.5% of this effect mediated via periodontitis.

Periodontitis had significant direct effect, and indirect effect through diabetes, on the incidence of CKD. Awareness about systemic morbidities from periodontitis should be emphasized.