The Use of Medically Required Dental Services by Youth with Intellectual/Developmental Disabilities in British Columbia, Canada

There is evidence that both children^1,2 and adults^3-5 who have intellectual/developmental disabilities (IDD) have poorer oral health than children and adults without IDD. The reasons for poorer oral health may include lack of access to appropriate dental care and delay in required dental care.⁶ The lack of professional care and early intervention can result in disease progression and the need for more invasive treatments, such as surgery and the use of general anesthesia.⁷ In a population of people with a variety of disabilities, Figueira⁸ found that tooth loss was greater for those who had fewer than 1 annual visit for dental care compared with those with more frequent dental care.

For people with IDD, problems accessing dental services can be because of a lack of trained and experienced dental professionals,^3,9 lack of specialized dental anesthesiologists, long waitlists and inaccessible or inappropriate physical facilities.^3,10 Scarcity of dentists and dental specialists in rural areas can affect access.¹¹ Access to dental care is also affected by the knowledge and experience of caregivers who support people with IDD.⁹ Social determinants of health factors, such as poverty¹ and the lack of insurance coverage or public dental plans,^3,12 also affect access to dental services for people with IDD.

In addition, individual factors, such as the type and severity of IDD, behaviour and comorbidities, can impact both daily oral hygiene and access to dental care.^3,13 Caregiver burden and caregiver age can affect the provision of daily oral hygiene.¹⁴ Lindemann¹⁵ found that among people with IDD, those who brushed their own teeth had fewer missing teeth than those who did not; those with a dentist of record had fewer decayed and more filled teeth; and people living at home with family or friends had a significantly lower DMFT index (decayed, missing and filled teeth) than those living independently or in facilities.

Life-course transitions have been identified as among the most difficult times for the health care of people with IDD.¹⁶ Biggs and Carter¹⁷ found that physical well-being in youth with IDD aged 13–21 years was associated with age; an increase in age predicted lower ratings of physical well-being. Nathenson and Zablotsky¹⁸ found a decline in the use of health care services, except for emergency services, by autistic youth transitioning to adult services.

For people in British Columbia (BC) receiving income or disability assistance, some of the costs of routine dental care are covered by direct payment to dentists through the Ministry for Social Development and Poverty Reduction.¹⁹ For adults receiving a disability allowance, the maximum coverage is $1000 over 2 calendar years. For children, the coverage is $2000 over 2 calendar years, plus $1000 over the same period to cover the cost of dental treatment in a hospital or special clinic while receiving general anesthesia.²⁰ Many advocates argue that these services are underfunded resulting in the majority of dentists in the province charging fees in addition to the coverage supplied through provincial social services.^21,22

The cost of additional dental care may be covered by provincial health services, but it must be deemed “medically required.” Services considered medically required in the general population are dental treatments that cannot be provided in a dental office and are complex enough to require treatment in a hospital or specialized clinic, often under anesthesia. However, routine dental treatments may be deemed medically required for youth with IDD if dentists do not feel able to treat them because of physical or behavioural issues. Few dental clinics are specifically designed for the routine care of people with IDD; therefore, for some people with IDD, hospital admission and use of general anesthesia may be required for routine dental care.²³

Addressing the gaps in service and providing adequate dental care for people with IDD is hampered by a lack of information. Most studies in this area have been small and have used convenience sampling; therefore, generalizing their results to larger populations is limited.⁵ As Lim⁵ states: “without sufficient robust data… it can be difficult to enact further change to address these [dental] health disparities” (p. 68). To address the lack of information, this study used population-level data to examine medically required dental care in youth with IDD in BC. The objectives were to compare such care for youth with and without IDD and for 2 age groups: 15–19 years and 20–24 years. In addition, the use of medically required dental care was examined for youth with various types of IDD. This is the first study in Canada to use population-level administrative health data to assess dental services among youth with IDD.

Methods

The study population was youth aged 15–24 years diagnosed with IDD. The comparison cohort was all other youth of the same age in BC in 2010–2019.

Population-level health data were obtained from the British Columbia Ministry of Health via Population Data BC, which provides researchers with linkages of administrative data and access to data extracts.²⁴ Population Data BC linked 3 data sets: a central consolidation file with demographic information on all individuals in BC²⁵; Medical Services Plan (MSP) payment files, which contain information for all fee-for-service care provided by physicians in BC²⁶; and the hospital separation file, which contains information on all hospital admissions in BC.²⁷ Data were linked using individual unique and study-specific codes that allow people to be anonymously identified across data sets. Diagnoses were identified using the International Classification of Diseases 9^th revision (ICD-9) codes in MSP data and the International Classification of Diseases 10^th revision (ICD-10) codes in hospital data. When patients visit a fee-for-service clinic or hospital, their diagnosis is assigned an ICD-9 or ICD-10 code for billing purposes. The BC Ministry of Health provided approval for data access and the University of British Columbia provided ethics approval (#H20-03028).

People with IDD were identified using ICD-9 and ICD-10 codes as described in the algorithm developed by Lin et al.²⁸ These codes identify a wide range of IDD (Appendix A). To ensure the identification of as many youth with IDD as possible, medical records from 1986 to 2019 were examined, and people with IDD were traced forward or backward in time. A diagnosis of IDD was either a primary diagnosis or a secondary diagnosis noted by physicians when the child visited the doctor. Type of IDD was subdivided into fetal alcohol syndrome (FAS), autism, Down syndrome and “other,” i.e., IDD not included in the first 3 groups. In addition, youth with multiple IDD diagnoses (e.g., autism plus Down syndrome or FAS plus autism) were grouped together as a separate variable and compared with youth with a single IDD diagnosis.

To examine the transition of youth from pediatric to adult services, subsets of the larger cohort were formed. In the subsets, youth were identified as 15 years old in 2010, 16 years old in 2011, 17 years old in 2012 etc., to 24 years old in 2019. The subset of youth with IDD was compared with a subset of the comparison cohort; the 2 groups were matched for age, sex and time (these subsets are referred to in the remainder of this paper as the transition subsets).

Dental diagnoses were identified using ICD-9 and ICD-10 codes (Appendix A) in MSP and hospital data. Dental diagnoses were services including dental exams, preoperative assessments for dental procedures and in-hospital procedures primarily for impacted teeth, abnormal tooth development and dental caries.

Overall descriptive statistics were reported for the larger group of youth with IDD and the comparison group; variables included sex, receipt of an MSP subsidy, income quintile and the health authority area in which the youth lived. The overall 10-year use of medically required dental services was reported for youth with IDD and for the comparison group. The smaller transition groups were also compared.

Programming and data analyses were conducted using Statistical Analysis System (SAS) v. 9.4 (SAS Institute Inc. Cary, NC, USA). Chi-square tests and t tests were used to compare proportions and means between youth with and without IDD. Multiple logistic regression was used to examine the binary outcome of having versus not having a medically required dental treatment, comparing youth with IDD to youth without IDD. SAS proc logistic fitted logistic regression models and estimated parameters for maximum likelihood using a Fisher’s scoring algorithm. Odds ratios (ORs) and 99% confidence intervals (CIs) were obtained. ORs were calculated for both the large group and the subgroups, comparing youth with and without IDD. Variables available in the administrative health data and used in OR calculations included sex, age, type of IDD, 5 geographic health authority areas and income quintile. In addition, MSP subsidy levels were available and were used as an indication of poverty. In BC, before 2020, MSP premiums were paid by individuals or employer plans. People with a low income received a provincial subsidy to cover their MSP costs. People with missing data were excluded from the study; there was no identified pattern to the missing data.

The difference-in-differences technique was used to compare mean number of dental visits of youth with and without IDD over time as the youth transitioned from pediatric to adult health services at age 19. Difference-in-differences methods compare changes over time in an outcome between exposed and comparison groups using repeated measures generalized linear models.²⁹ The analyses compare population averages between 2 periods for exposed and comparison groups.

Results

Descriptive statistics can be found in Table 1. Using all 10 years of data, 20 591 youth with IDD were identified. This represents 1.57% of the population of youth aged 15–24 in BC in 2010–2019. The cohort with IDD included a greater proportion of males than the comparison group. In the IDD group, 35% of patients received an MSP subsidy compared with 18% of the comparison cohort. A greater proportion of people with IDD occurred in the lowest income quintile compared with the group without IDD. In the transition subset of youth with IDD, the distribution of sex, income and receipt of an MSP subsidy was similar to that of the larger groups.

When hospital data were examined, 2 dental issues (caries and impacted teeth) were among the 5 most frequent reasons for admission to hospital for youth with IDD. For youth without IDD, dental issues did not appear among the 20 most frequent reasons for hospital admission; for this group, the 5 most frequent reasons for admission were related to giving birth and mental health.

Using all 10 years of data and the large group of youth with IDD, we found that, holding all other variables constant, youth with IDD had an OR of 7.002 (99% CI 6.727–7.287) for a medically required dental visit compared with youth without IDD (see Table 2). In addition, holding all other variables constant, females had greater odds of a medically required dental visit compared with males, and youth receiving an MSP supplement had greater odds than those who did not receive an MSP supplement.

For youth aged 15 in 2010, the odds of having a medically required visit for a dental issue were 9.420 times greater for youth with IDD than for youth without IDD (Table 3). As youth aged, the odds declined but still remained higher in youth with IDD compared with those without IDD.

In the unadjusted repeated measures ANOVA difference-in-differences, the mean number of diagnoses per person for medically required dental issues decreased significantly over time for youth both with and without IDD (Table 4). The difference in decrease between the 2 cohorts was significant.

Using all 10 years of data and the large group of youth with IDD and holding all other variables constant, results showed that compared with youth with Down syndrome, youth with FAS (1.263, 99% CI 1.027–1.552), and youth with “other” diagnoses (1.348, 99% CI 1.126–1.614) had greater odds of a medically required oral health care visit (Table 5). Youth with autism did not have significantly different odds of a medically required dental visit compared with youth with Down syndrome. Youth with multiple IDD diagnoses had greater odds of a medically required oral health care visit compared to youth with a single IDD diagnosis (2.386, 99% CI 2.153-2.644).

Discussion

Previous studies have shown that people with IDD have poorer oral health compared with people without IDD. The current study used administrative health data to examine medically required dental visits of youth w…