Integrated Diabetes and Oral Health Care in Oman

Type 2 diabetes mellitus (T2DM) is an important public health problem in Oman. Periodontal disease is common among people with diabetes, and the relationship between diabetes and periodontal disease is bidirectional. Poor glycaemic control may contribute to periodontal inflammation, while periodontal inflammation may adversely affect metabolic control. Despite this relationship, diabetes education commonly focuses on glycaemic control and general diabetes self-management, with limited structured integration of oral-health education and behavioural approaches.

This study is a multicentre, two-arm randomized controlled trial designed to evaluate the effectiveness and cost-effectiveness of an integrated diabetes-oral health educational intervention based on the Health Belief Model (HBM). The study will recruit 290 adults with T2DM (145 participants per group) from participating diabetes clinics in Oman. Participants will be allocated to either the intervention group or the control group.

Participants assigned to the intervention group will receive six structured, individual HBM-based educational sessions, approximately 30 minutes each, delivered over 12 weeks. The intervention addresses diabetes and oral-health risk awareness; the severity and consequences of periodontal disease in people with T2DM; benefits of glycaemic control and oral hygiene; barriers to oral-health self-care and practical solutions; toothbrushing, interdental cleaning, and self-monitoring skills; and maintenance planning and relapse prevention. Sessions will include structured educational material, individualized advice, and goal-setting. Participants in the control group will continue to receive standard diabetes care and education.

Data will be collected at baseline and at 3, 6, and 12 months, as appropriate for each outcome. The primary outcome is change in HbA1c from baseline to 12 months. Secondary outcomes include periodontal clinical indicators, diabetes and oral-health self-management behaviours, HBM constructs, oral health-related and general health-related quality of life, psychological well-being, diabetes distress, healthcare utilization, and direct medical costs. An economic evaluation will assess the cost-effectiveness of the intervention.

As an exploratory component, participants will undergo periodontal assessment to estimate the prevalence of previously undiagnosed periodontal disease and examine its association with glycaemic control. The study will also explore associations between changes in periodontal status and oral microbiome profiles.

• Health Belief Model-Based Integrated Diabetes-Oral Health Educational Intervention (Behavioral): Participants will receive an individualized Health Belief Model-based integrated diabetes-oral health educational intervention in addition to routine diabetes care. The intervention consists of six individual face-to-face educational sessions delivered over 12 weeks, with each session lasting approximately 30 minutes. The sessions address diabetes and oral health risk awareness, severity and consequences of periodontal disease, benefits of glycaemic control and oral hygiene, barriers to oral health self-care and practical solutions, brushing and interdental cleaning and self-monitoring skills, and maintenance planning and relapse prevention. Each session includes structured educational material, individualized advice, and simple goal-setting.
• Standard Diabetes Education and Routine Care (Behavioral): Participants will receive standard diabetes education and routine clinical care provided by existing diabetes services. Routine education includes advice on diet, medication adherence, physical activity, and blood glucose monitoring. Participants will not receive the structured Health Belief Model-based integrated diabetes-oral health educational intervention.

Primary outcomes

• Change in Glycated Hemoglobin (HbA1c) From Baseline to 12 Months [Baseline to 12 months]: Change in HbA1c (%) from baseline to 12 months will be used to assess the effect of the intervention on glycaemic control. HbA1c will be measured using blood samples processed in a certified hospital laboratory. The between-group difference in change over time will be evaluated.

Secondary outcomes

• Change in Probing Pocket Depth (PPD) [Baseline, 3 months, 6 months, and 12 months]: Probing pocket depth will be measured in millimeters (mm) using a periodontal probe at six sites per tooth. Mean probing pocket depth will be calculated for each participant. Change in mean probing pocket depth from baseline will be compared between the intervention and control groups. Lower values indicate better periodontal health.
• Change in Diabetes Self-Management Behaviors [Baseline, 3 months, 6 months, and 12 months]: Diabetes self-management behaviors will be assessed using the Summary of Diabetes Self-Care Activities (SDSCA) questionnaire. The SDSCA assesses the frequency of diabetes self-care activities over the previous 7 days. Items are scored from 0 to 7 days, with higher scores indicating more frequent performance of the assessed self-care behavior. Change in SDSCA scores from baseline will be compared between the intervention and control groups.
• Healthcare Utilization [From baseline through 12 months]: Healthcare utilization will be assessed as the number of healthcare services used by each participant during the study period, including relevant outpatient visits and other healthcare contacts recorded as part of the study. Healthcare utilization will be compared between the intervention and control groups. Higher values indicate greater healthcare resource utilization.
• Change in Oral Health-Related Quality of Life Assessed Using the Oral Health Impact Profile-14 (OHIP-14) [Baseline, 3 months, 6 months, and 12 months]: Oral health-related quality of life will be assessed using the 14-item Oral Health Impact Profile (OHIP-14). Each item is scored from 0 (never) to 4 (very often), producing a total score ranging from 0 to 56. Higher total scores indicate poorer oral health-related quality of life. The change in total OHIP-14 score from baseline will be compared between the intervention and control groups.
• Direct Medical Costs [Baseline through 12 months]: Direct medical costs associated with healthcare utilization will be estimated from the health-system perspective and reported in Omani Rial (OMR) per participant. Mean direct medical costs over the study period will be compared between the intervention and control groups. Higher values indicate greater healthcare costs.

Sex: All, ages: 35 Years to any

Inclusion Criteria:

* Aged 35 years or older.
* Confirmed diagnosis of type 2 diabetes mellitus (T2DM), documented in the medical record for at least 12 months.
* Able to understand Arabic or English.
* Able to provide written informed consent.
* Able to attend the scheduled educational sessions and follow-up visits.

Exclusion Criteria:

* Pregnant or breastfeeding.
* Cognitive impairment or severe mental illness limiting participation.
* Active systemic infectious diseases such as tuberculosis, syphilis, or HIV.
* Use of medications that may significantly affect glucose metabolism or gingival health, such as long-term systemic corticosteroids, immunosuppressants, phenytoin, or calcium channel blockers.
* Severe periodontitis requiring immediate surgical intervention.
* Participation in another diabetes or oral health intervention trial.
* Unable to comply with the follow-up schedule.