Cost-effectiveness of periodontal management in diabetes patients

Background + Aims

• Periodontitis and type 2 diabetes are linked through a bidirectional relationship: diabetes increases the risk and severity of periodontitis, while periodontal inflammation worsens glycaemic control.
• Systemic inflammation, driven by cytokines, contributes to complications such as cardiovascular disease and stroke. Associations between severe periodontitis and cardiovascular diseases have also been well-established.
• Japan faces a significant burden from both conditions: there is high prevalence of both type 2 diabetes (13.1% overall, 19.7% in those over 65 years) and periodontitis (53.6% overall, 62.7% in those over 65).
• Studies suggest that periodontal therapy may reduce HbA1c levels and improve systemic health outcomes. However, prior research on its impact on healthcare costs and hospitalisation rates has yielded mixed results.
• The study aims to assess whether regular periodontal management in patients with type 2 diabetes reduces healthcare expenditure, all-cause hospitalisation, stroke hospitalisation, and insulin therapy initiation over three years.

Materials + Methods

• This is an observational study using claims data from Japan’s National Health Insurance (NHI) and the Medical Care System for the Elderly Aged 75+.
• Study Population:
  • Inclusion criteria: Individuals aged 35 or above prescribed medication for type 2 diabetes in the fiscal year 2015 with at least 3 years of claims data.
  • Exclusion criteria: Those prescribed insulin in the previous 2 years for the analysis of periodontal management and insulin introduction.
• Exposure Groups:
  • Regular periodontal management: Patients receiving periodontal care in both the first and second years.
  • Intermittent care: Patients receiving periodontal care in either the first or second year.
  • Other dental treatments: Patients with non-periodontal dental care only.
  • No dental care: Patients who received no dental treatment in the two years.
• Periodontal treatments included probing, scaling, root planing, subgingival curettage, periodontal surgery, and supportive periodontal therapy. Frequency was categorised as annual or semi-annual.
• Outcomes Measured:
  • Primary outcome was total healthcare expenditure in the third year (medical, dental, and pharmacy costs).
  • Secondary outcomes included all-cause hospitalisations, hospitalisations due to ischaemic stroke or myocardial infarction, and insulin initiation as a marker of worsening diabetes.
  • Adjustments were made for age, sex, comorbidities, and prior healthcare expenditure to account for baseline differences. Comorbidities were identified using a validated list of 32 conditions.
• Statistical Analysis:
  • Generalised linear models (GLM) with a gamma distribution were used for healthcare expenditure, accommodating skewed cost data.
  • Logistic regression assessed odds of hospitalisation and insulin initiation.
  • Sensitivity analyses explored the impact of management intensity and frequency on outcomes.

Results

• Study Population:
  • 16,583 patients aged ≥35 received diabetes medications in 2015 and had three years of claims data.
  • A sub-group analysis (population for insulin analysis) excluded 3,361 prior insulin users to evaluate insulin initiation rates (n = 13,222).
  • 9% received periodontal management both years; 55.3% received no treatment.
  • 3% received management every 6 months during the first two years.
• Effect of Periodontal Management on Healthcare Expenditure:
  • Healthcare expenditure 4%-6% lower in groups receiving periodontal management vs. no treatment.
  • Previous two years’ expenditure was a significant predictor.
• Effect on Hospitalisations and Insulin Introduction:
  • Reduced odds for all-cause hospitalization and introduction of insulin in the ‘every year’ group.
  • All-cause hospitalisation odds reduced by 10% (aOR: 0.90).
  • Stroke-related hospitalisation odds reduced by 40% (aOR: 0.60).
  • 23% lower odds of insulin initiation in regular care recipients (aOR: 0.77).
  • No significant reduction in myocardial infarction hospitalisation.
• Effects of Differences in Periodontal Management:
  • All management groups showed reduced healthcare expenditure.
  • Reduced hospitalisations and insulin introduction associated with specific management patterns.
• Management Intensity:
  • Both maintenance care and active periodontitis treatment yielded comparable reductions in costs and hospitalisation risks.
  • Benefits were consistent regardless of treatment frequency (yearly vs. half-yearly).

Limitations