Comparison of compliance and outcomes in adolescents with type 1 diabetes mellitus attending a co-located pediatric and transition diabetes service

Introduction

Transition is a particularly important life event for adolescents with chronic medical conditions as it involves transfer from pediatric to adult health care. The transition coincides with the stage of life known as emerging adulthood (18–24 years). This age is often marked by geographic, economic and emotional separation from the parental home. Feelings of invulnerability and a tendency to reject adult control are often present. In particular, this may further limit receptiveness to recommendations for diabetes management thus resulting in suboptimal diabetes care. There are studies that have expressed the transfer to adult care may be accompanied by poor glycemic control and decreased clinic attendances [1, 2].

Patients transitioning to an adult provider have a 2.5-fold risk of poor glycemic control by the time of their first adult visit, with elevations in glycosylated haemoglobin (HbA_1c) from 7.5% in their final pediatric visit to 9.2% by their first adult visit [3]. Data from the T1D Exchange indicate that glycemic control during the young adult period is poor, with higher haemoglobin HbA_1c levels than in any other age group [1].

The term ‘transition’ implies a gradual, co-ordinated shift from a pediatric, family-centred model to an adult, patient-centred model. Its timing and tempo depend on patients’ physical and psychological states, as well as practical considerations.

The transition is a vulnerable period marked by changes in physical, emotional, and social domains [4]. Changes in health self-management place emerging adults at risk for poor health later [5]. Challenges can include reluctance to end a trusting relationship with the pediatric team, worries about ‘starting over’ with a new care provider, and discomfort with the unfamiliar adult medical setting which can have shorter visits and less emphasis on multi-disciplinary care [6, 7].

A successful transition cannot always be predicted based on clinical factors, although low hospital attendances and poor glycemic control at the time of transition might negatively affect transition. However, there is no clear consensus on the definition of a successful transition, and there is a lack of high-quality evidence on which a transition plan can be based. However, there have been a few interventions that have attempted to address transition issues which include the transition to an adult service with dedicated young adult clinics [8, 9]. In a pilot study of a support transition coordinator, Van Walleghem et al. [10] showed that medical engagement improved. However, there was no evidence of improved short-term medical outcomes. Holmes-Walker et al. [11] also tested a program with a transition coordinator and demonstrated improved clinic attendance and reduction in admissions for diabetic ketoacidosis. In an analysis of the Ontario Diabetes Database, Nakhla et al. [12] showed that patients who remained with the same physician after transition were at lower risk for hospitalization.

Therefore, the aims of this study were to determine if there was a difference in glycemic control, hospital admissions, microvascular complications, and clinic attendances in type 1 diabetic patients attending a transition diabetes clinic, depending on where they received prior diabetes care. Prior diabetes care were from either the co-located pediatric diabetes service or from external referral sources.

To our knowledge, our study represents the largest retrospective sample size to date of a co-located pediatric and transition diabetes service. We hypothesised that adolescents who transition within the same facility, might result in having better outcomes.

Methods

Results

Of the 356 patients attending the transition clinic, 121 patients were internally referred from the hospital’s pediatric clinic (IRG), and 235 patients were externally referred from other sources pediatric (ERG). Out of the ERG, 56 patients were referred from the local tertiary Children’s Hospital, 39 patients were self-referred, 37 patients were referred by their local general practitioner, 35 patients were referred from the inpatient ward and 26 patients from the emergency department of the same hospital, 25 patients were referred by private endocrinologists, and 17 patients were referred from other metropolitan hospitals.

Table 1 describes the demographic details and insulin treatment modalities of the patients according to their referral sources. The mean age of diagnosis in the IRG was significantly lower compared to the ERG (p<0.001). The mean age of transition in the internal group was slightly lower than the ERG (17.1 ± 1.7 vs. 18.8 ± 2.6 years respectively, p<0.001).

HbA_1c levels were measured during the transition appointments. Mean HbA_1c levels at the time of transition was lower in the IRG compared to the ERG (9.1 ± 1.9% vs. 9.7 ± 2.6% respectively, p=0.04). To analyse the impact of time, univariate paired t-testing was performed comparing 6 and 12 month HbA_1c to the pretransition level. Significant improvements were only seen in the ERG (p<0.001), but in the IRG, the pretransition HbA_1c did not significantly change over the course of the study (p=0.15 at six months, p=0.78 at 12 months) (Figure 1). In addition, Table 2 describes the repeated measures ANCOVA analysis comparing these serial HbA_1c’s between the two referral sources whilst controlling for gender, age, duration of diabetes, and socioeconomic status. There was a difference between referral groups before and after transition controlling for these confounders (F=7.49, p<0.001).

Figure 1:

Graphical representation of mean HbA_1c between referral sources.

Table 3 describes the clinic attendances for medical and allied health reviews. More patients in the ERG (99%) attended the 1st transition appointment (either medical or allied health) than the IRG (94%) (p<0.01). There was no difference between the IRG and ERG groups in retention of patients with the transition service at 24 months (85 vs. 82%, p=0.41)

There were more hospital admissions due to acute diabetes-related complications, including DKA and hypoglycaemia in the IRG compared to the ERG (17 vs. 8% respectively, p=0.01), which was similarly seen in the rates of chronic diabetic complications including diabetic retinopathy, peripheral neuropathy, and micro-albuminuria (20 vs. 9% respectively, p<0.01). There were higher rates of mental health issues reported in the ERG that, however, did not reach significance (p=0.52) (Table 4).

The outcomes of hospital admissions (DKA and hypoglycaemia combined) and microvascular complications between the two groups were further analysed by logistic regression to account for the confounders, of age, duration of diabetes, gender, and socioeconomic status (Table 5). Despite controlling for these confounders there was still a difference in hospital admissions between the IRG and ERG groups (OR 0.39, 95% CI 0.19–0.8, p=0.01). In regard to microvascular complications, there was still a difference between the groups with more complications occurring in the IRG compared to the ERG (OR 0.51, 95% CI 0.26–0.99, p=0.046). In addition, the duration of diabetes was found to significantly contribute to this finding (OR 1.10, 95% CI 1.03–1.17, p=0.004).

Discussion

We described the outcomes of 356 adolescents (>16 years of age) and young adults with type 1 diabetes mellitus attending the diabetes transition clinic in a Western Sydney metropolitan hospital between 2008 and 2016. We wanted to explore whether there were better outcomes of having a co-located pediatric and transition clinic. We found that although patient engagement was better, this was not associated with better glycemic control, less hospital admissions, and microvascular complications following the transition.

Conclusions

To our knowledge, this is the largest retrospective study to date of a co-located pediatric and transition diabetes service, which compares the transition outcomes between two groups of patients who were referred from different referral sources. Our results highlight that despite serial HbA_1c’s being comparatively better in the patients referred from the ERG compared to the IRG, their clinic attendance was the opposite. We also found that hospital admissions and microvascular complications were less in the ERG as well. The shorter duration of diabetes in the ERG could explain the lower rate of microvascular complications, however this did not contribute to the difference seen with hospital admission rates between the groups. Apart from better engagement in follow-up clinics, our study did not identify further strengths of a co-located pediatric and transition diabetes clinic. As we did not obtain prospective patient satisfaction data about the transition process between the two referral groups, we can only speculate on this important facet of transition. Further research is needed to determine if other strategies could be implemented to optimise the transition process in diabetes care.