HbA1c outpredicts every other glycemic marker for periodontitis severity

Periodontitis and diabetes are known to interact bidirectionally, but data from South Asian populations — where both conditions are highly prevalent and often under-managed — remain sparse. This hospital-based cross-sectional study examined 396 adult dental outpatients in Nepal, stratified into mild, moderate, and severe periodontitis groups (132 each) using the 2017 World Workshop classification criteria, with patients showing an aggressive-periodontitis-type pattern excluded. Fasting blood glucose (FBG), postprandial blood sugar (PPBS), and glycated hemoglobin (HbA1c) were measured alongside standard periodontal parameters.

All three glycemic markers worsened stepwise with periodontitis severity (Kruskal-Wallis, p<0.001). Among them, HbA1c showed the strongest correlation with probing depth and clinical attachment loss. In ordinal logistic regression, HbA1c emerged as the single strongest independent predictor of periodontitis severity, ahead of age and current smoking status.

The cross-sectional design cannot establish which comes first — glycemic dysregulation or periodontal destruction — and the hospital-based sample may not generalize to the broader Nepalese population. Even so, the consistency of the gradient across three independent glycemic measures, and the primacy of HbA1c specifically, adds to a now-substantial body of evidence that long-term glycemic control (rather than a single fasting glucose reading) is the more clinically meaningful marker to track alongside periodontal status. For practice, this argues for treating HbA1c — obtainable from the patient's physician or via point-of-care testing — as a routine part of periodontal risk stratification, and for framing periodontal therapy explicitly as part of integrated metabolic care in patients with poor glycemic control, consistent with the broader literature on the diabetes-periodontitis relationship.