Community periodontal index based screening findings and healthcare expenditures: a 7-year cohort study of male employees in Japan

Abstract Background The global economic burden of dental diseases, particularly periodontitis, is substantial, with growing evidence linking these conditions to systemic diseases such as diabetes and cardiovascular diseases. Although international studies have demonstrated that periodontal treatment can mitigate medical costs, comprehensive research examining the relationship among oral health, healthcare expenditures, and systemic disease onset is still scarce, particularly in Japan. Therefore, this study examined the associations among oral health, medical and dental expenditures, and the incidence of lifestyle-related diseases, using annual health checkup data. Methods This 7-year cohort study analyzed data from 467 male employees who participated in annual health and dental check-ups from 2007 to 2014. Participants were categorized into CPI ≥ 3 group (at least one tooth) and CPI < 3 group based on the community periodontal index. We compared baseline characteristics and healthcare expenditures (medical, dental, pharmaceutical and total healthcare) between two groups. Longitudinal changes in glycated hemoglobin (HbA1c) levels were evaluated using a mixed model for repeated measures. Results Participants in the CPI ≥ 3 group ( n = 87) were significantly older than the CPI < 3 group ( n = 380). Regarding median annual expenditures, dental expenditure (¥12,760 vs. ¥7,030; p = 0.01), and total healthcare expenditure (¥97,030 vs. ¥51,415; p = 0.03) were significantly higher in the CPI ≥ 3 group in unadjusted GLM analyses, whereas medical expenditure (¥41,160 vs. ¥21,770; p = 0.11) was not. In age adjusted analyses, only dental expenditure remained independently and significantly higher (mean difference: ¥12,692; p = 0.03). No significant difference in HbA1c trajectories or the risk of exceeding an HbA1c threshold of 5.6% or 6.5% was observed between the two groups. Conclusion Our findings suggest that a CPI-based screening finding of ≥ 3 is independently associated with higher long-term dental expenditures. Promoting corporate CPI-based screening as a low-threshold, population-level marker has the potential to serve as a strategy for identifying individuals at risk for elevated healthcare burdens.