Prediabetes is characterised by elevated blood glucose, but not satisfying the diagnostic criteria for diabetes
[10]. People with prediabetes are at high risk of developing type 2 diabetes and have an increased risk of cardiovascular disease, coronary heart disease, stroke, and all-cause mortality
[11]. Women with prediabetes before pregnancy have a higher risk of developing Gestational Diabetes Mellitus
[10]. Recent studies have also demonstrated that periodontal inflammation parameters including alveolar bone loss
[12] and bleeding on periodontal probing
[13], are worse in individuals with prediabetes compared to healthy individuals.
It has been estimated that three-quarters of people with diabetes receive a “delayed diagnosis,” meaning that within six months of diagnosis, they have already developed at least one diabetes-related comorbidity or complication
[14]. Early detection of type 2 diabetes and prediabetes should enable optimal management, and in the case of prediabetes, reduce the risk of developing type 2 diabetes and cardiovascular disease. Screening can be defined as ‘‘the examination of asymptomatic people in order to classify them as likely or unlikely to have a disease”
[15]. For individuals with undiagnosed prediabetes and type 2 diabetes, screening often represents the first step in obtaining a diagnosis of diabetes, which then may result in the initiation of interventions that can delay or even prevent diabetes-associated complications.
Most disease screening in Australia occurs opportunistically, often undertaken when patients attend healthcare professionals for reasons unrelated to the disease. When individuals consult with a GP, it is often for a problem and not a checkup
[19], and awareness and application of the AUSDRISK has been found to be low amongst Australian GPs
[17]. Given the bidirectional relationship between diabetes and periodontal disease, the oral manifestations of diabetes are common and readily identifiable by oral health professionals (OHPs). Since a significant proportion of the population has an annual dental check-up
[20], the dental setting affords an additional location for administering a diabetes risk assessment.
2. Rates of Referral Compliance
For the papers included in this review, the mean referral compliance was 54% of referred patients. The highest referral compliance rate of 90% was reported in the Swedish study
[21] while the lowest rate of 25% was reported in the Australian study
[22]. It should be noted that some studies followed up with participants for up to three years after screening
[21] while others followed up for only two weeks to six months
[23][24][25]. Furthermore, confidence intervals were not always reported for all referral compliance rates, making it difficult to ascertain the variations or make comparisons. Nevertheless, the generally low level of referral compliance amongst screened patients represents a considerable barrier to effective diabetes screening in the dental setting. Comparable low rates of referral compliance have been reported in the literature for opportunistic diabetes screening in other primary care settings, including pharmacies and emergency departments. A systematic review and meta-analysis of diabetes screening conducted in community pharmacies concluded that although screening identified a significant number of individuals at a high risk of having diabetes, many of these individuals did not attend a follow-up appointment with their HCP
[26]. Studies reporting referral compliance after diabetes screening in an Emergency Department have found attendance rates for a confirmatory follow-up to be between 38%
[27] and 73%
[28].
Similarly, research investigating referral compliance following screening for other medical conditions has found low rates of follow-up attendance. When the dental setting has been utilised to screen for sleep apnoea, less than half of referred participants attended medical follow-ups
[29][30]. Screening efforts for diabetic eye disease
[31], elevated cholesterol
[32], and follow-up after an abnormal pap smear result
[33] have also been hampered by low rates of compliance to post-screening referral.
3. Barriers and Facilitators to Referral Compliance in the Dental Setting (Patient Factors)
Factors impacting compliance to referral are complex and are linked with parameters, such as age, gender, stage of condition and disease complications
[31][33].
Six publications reported patients’ reasons for choosing to comply with referral advice or not, after diabetes screening in a dental setting. One study identified patient demographic characteristics that may predict attendance to medical follow-up, finding older participants were more likely to comply with referral advice than younger participants although no specific reasons were elucidated
[34]. Research in other primary care settings has reported demographic variables, such as increasing age for cervical cancer screening
[33], have facilitated referral compliance following the medical screening. Hui et al. suggested this may be because younger women (under 30 years old) might be less able to manage the psychological distress associated with cervical cancer risk and its medical follow-up. Social and economic factors, such as unemployment, lack of social support, andlow education level, have also been found to negatively influence attendance following screening for cervical cancer
[35].
The diabetes risk assessment results are interpreted by the OHP, who then communicates the findings to the participant. If a referral is indicated, it is the choice of the individual to act upon the advice or not. The way risk is perceived by the screening participant may influence whether they perform behaviours that reduce or prevent the risk
[36]. The perception that diabetes was not serious enough to justify a follow-up visit
[24][37], or that other health concerns took precedence
[22], were reported as reasons for non-compliance in several studies in this review. Rosedale et al. found that patients would either perceive diabetes screening as being an opportunity to act, and this would encourage referral compliance, or a burden, and therefore, not attend medical follow-up
[37].
An individual’s knowledge about the medical condition in question may also influence their perception of risk
[36]. A lack of knowledge about diabetes
[37] was reported as a barrier to referral compliance in this review. Knowledge about the condition being screened for has been reported as a facilitator of referral compliance for some conditions, such as type 2 diabetes
[38] and a barrier, because of the distress and fear knowledge of the condition creates for breast
[39] and cervical cancer
[35].
The screening protocol employed in the dental setting may also influence the participants’ risk perception and thus referral compliance. A study that employed two screening tools: A questionnaire and a point of care Hb A1c test, found the number of positive screening results a participant received would influence their decision whether to attend a follow-up or not. Individuals that screened positive for both tests, were three times more likely to attend a medical assessment
[23]. A study that explored patients’ perceptions of, and reactions to a diabetes screening protocol in the primary care setting, found patient perceptions changed as they progressed through a three-step screening pathway
[38]. The initial screening steps were often viewed as unimportant, and it was not until the final diagnostic test (step three), that type 2 diabetes was considered a strong possibility. The authors suggested that participants experienced a process of psychological adjustment from the first screening test which was approached without considering its implications, to the final test where they were confronted with the possibility of having diabetes.
Diabetes screening conducted in the dental setting requires a referral pathway from OHP to GP, and one potential barrier to completing the screening protocol identified by Mariño and colleagues
[22] was arranging a medical follow-up appointment for screened individuals. Less than half of screened respondents in this study reported that the booking of medical appointments was easy, and this may have contributed to some individuals at high risk of developing diabetes, delaying or not receiving a follow-up assessment from their GP. However, part of this research was conducted during the COVID-19 pandemic when restrictions on movement were in place, and two study participants cited COVID-19 as a reason for not attending follow-up. Additional barriers reported in the literature that may hinder booking a medical follow-up appointment have included cost
[22][24], the individual relocating overseas
[22][24], time constraints
[24][40], cultural and religious reasons
[24], and in one study simply losing the referral letter
[24].
4. Barriers and Facilitators to Referral Compliance in the Dental Setting (OHP Factors)
Several papers in this review identified OHP factors, such as their communication skills, and the OHP and patient relationship, as a predictor of patients’ compliance with referrals. Rosedale et al. reported having a positive interaction with the OHP and good communication skills increased the likelihood of referral compliance
[37]. Studies of disease screening have identified the role of HCP factors, such as effective communication
[29], the screened individual having an existing relationship with an HCP
[41], and positive interactions between the HCP and patient
[38], facilitating referral compliance. Conversely, poor communication and a lack of rapport with the HCP has been identified as a barrier to referral adherence
[42]. This suggests that the OHP providing information about the medical condition being screened for, engaging participants in the discussion, and as reported in one study, organising post-screening reminder calls
[37], may encourage referral compliance.
The location of the oral health service where screening was undertaken, influenced the referral compliance in one study which found 78 % of individuals screened in a community clinic attended medical follow-up, compared with 21 % of those that were screened in a private dental practice
[43]. The underlying reasons for this difference are not clear, as most participants simply chose not to seek care without providing an explicit explanation.
5. Behavioural Model That Explains Patient’s Compliance to Referral Recommendations
The development of a behavioural model enables us to understand behaviours and the factors that influence them. It is only by understanding the determinants of behaviour, that effective evidence-based interventions may be designed to change it. This scoping review identified only one paper that proposed a behavioural framework that may explain an individual’s decision to attend medical follow-ups post-diabetes screening
[37]. Adapting a model developed to explain barriers to hypertension treatment and follow-up
[44], Rosedale et al. proposed that intention, capability, healthcare system, and fear and denial barriers, influenced referral compliance. They categorised intentions, as the attitudes and motivation towards seeking medical follow-up. Capability barriers related to knowledge about the condition (type 2 diabetes) and understanding the importance of follow-up. Healthcare system barriers included affordability, acceptability and access to medical care. The final component of the model was fear of the consequences of positive screening, participants’ denial about the association between prediabetes and diabetes, and not believing themselves to have diabetes
[37].
6. Conclusion
This scoping review highlights a gap in our knowledge regarding the barriers and facilitators that influence referral compliance following a diabetes risk assessment in the dental setting. Further research is indicated to understand what the barriers and facilitators to referral compliance behaviour are, to enable the development of interventions to maximise the number of patients that follow up the advice of their HCP and complete the diabetes screening pathway.