Trends in emergency department visits for non-traumatic dental conditions in Ontario from 2006 to 2014.

Singhal, Sonica ; McLaren, Lindsay ; Quinonez, Carlos 等

Emergency department (ED) visits for non-traumatic dental conditions (NTDC) continue to attract advocacy and policy attention in Canada. (1,2) Generally, ED visits for NTDC are viewed as an inefficient and costly way of dealing with such dental problems, which are most often basic in nature and best treated in office-based ambulatory dental settings. (3-6) In fact, ED visits for NTDC are now viewed as a consequence of poor access to dental care and are used in some jurisdictions as an indicator in this regard. (6)

National-level data in the United States suggest that, over a 10-year period, ED visits for NTDC increased and at a faster rate than for all ED visits combined. (7) Yet, in Canada, most studies on ED visits for NTDC present data for only one or two years; (4,5) only one has presented trend data, but it was limited to homeless adults over a four-year period in one Ontario municipality. (3) Trend data are important, as they give researchers and policy-makers the ability to explore patterns in a given outcome, and allow for hypothesis formulation on potential environmental exposures and their effects on such trends.

Further, though most studies on ED visits for NTDC in Canada quantify the burden, they do not report on the predictors of such visits either at the individual or area-based level. (4,5) What is known has relied on data on self-reported ED visits for NTDC in Canada, and suggests that cost barriers to dental care, oral pain, and bed days due to dental problems are predictors of such visits. (8,9)

As a result of the above, this study aims to assess trends in ED visits for NTDCs in Ontario from 2006 to 2014, and to explore socio-demographic and geographic predictors of such visits.

METHODS

Data aggregated at the region level (14 Local Health Integration Networks, or LHINs) for ED visits in Ontario for NTDCs related to the hard tissues of teeth (described below) were obtained from the Canadian Institute for Health Information's (CIHI) National Ambulatory Care Reporting System (NACRS). Population-based data (as these included everyone from the existing administrative data and not just a representative sample) were available from fiscal year 2006/2007 to 2014/2015. Data included both the number of people who made visits to EDs and the number of visits they made.

Cells with four or fewer observations were suppressed to avoid identification.

Based on the census year 2006 (as long forms were not mandatory in 2011), postal codes of individuals were used to assign dissemination areas (DA), which in turn were linked to neighbourhood characteristics: urban/rural setting, income, and proportion of immigrants. Details are as follows: 1) Neighbourhood urban/rural: Census metropolitan area (CMA) or census agglomeration (CA) of [greater than or equal to] 10 000 residents is considered urban and of <10 000 is considered rural;2) Neighbourhood income quintile: CMAs/CAs are divided into income quintiles ranked 1 to 5 (poorest, poorer, average, richer and richest) according to the percentage of their population below the low-income cut-off, where low-income refers to a total family income in the year preceding the Census that is below that year's Statistics Canada low-income cut-off, which varies according to family size and CMA/CA size; and 3) Neighbourhood immigrant tercile: the DAs are divided into three approximately equal-sized groups based on percentage of immigrants: with the highest, the middle and the lowest tercile corresponding to immigrant proportions of 63%, 37% and 10% respectively. (10)

In NACRS, there are two relevant variables: the presenting complaint list (data element 136) and the ED discharge diagnosis (data element 137). (11) The presenting complaint list includes self-reported reasons and symptoms for seeking medical care, and the ED discharge diagnosis shortlist (CED-DxS) includes diagnoses in common terms, which are mapped to ICD-10-CA codes. (11) We included cases for which the discharge diagnoses (ICD-10-CA code) confirm a non-traumatic dental condition related to the hard tissues of teeth, such as dental caries (K02.9), periapical abscess without sinus (K04.7), and tooth ache (K08.87). Conditions related to soft tissues of the oral cavity, such as ulceration or stomatitis of gum, tongue and/or cheek mucosa, or involving salivary glands, were not included since physicians can also treat these oral conditions. As the purpose of this research is to assess the burden on the health care system due to dental diseases that can solely be resolved by dental professionals, any oral condition which can be handled by other health professionals was excluded. People with mild or moderate intellectual and developmental disabilities (IDDs) (12) are generally at an increased risk of dental disease due to co-morbidities, dietary practices, behavioural challenges, and the potential need for extra attention in oral hygiene maintenance (e.g., tooth brushing); though these individuals can be treated successfully in the general practice setting, ED visits are not necessarily preventable for them, and therefore they were excluded from analysis. (13,14) Given the above, if the discharge summary included ICD codes related to dental trauma, oral soft tissues or developmental disability, those cases were excluded from the analysis.

Descriptive analysis was performed. Data were examined for the whole of Ontario and stratified by LHINs. Both number of people and number of visits made by those people (some people visit multiple times), stratified by sex and age groups (0-5, 6-18, 19-64, and 65+ years), were tabulated for nine consecutive years. Rates were calculated by dividing the number of people visiting the ED in each fiscal year by the projected population based on Statistics Canada estimates for that fiscal year. (15) Kendall's tau, a non-parametric test, was utilized to conduct a time trend analysis of visits over the nine-year time period. (16) We also examined both number of people and number of visits stratified by neighbourhood characteristics; however, rates could not be calculated for income quintiles and immigrant terciles because of neighbourhood migration creating uncertainty in available population denominators.

RESULTS

From 2006 to 2014, on average, 53 618 visits were made each year to EDs in Ontario for NTDCs by approximately 44 848 people. Over the nine-year period of observation, this totals approximately 482 565 visits made by 403 628 people.

In terms of rates, each year approximately 341/100 000 people visited EDs for NTDCs. Stratified by sex, each year approximately 24106 men (413/100000) and 20 742 women (351/100000) visited EDs for NTDCs (Table 1). By age, each year children aged 0-5 years was the age group that visited EDs for NTDCs the most at an average of 718 per 100 000, and people aged 65+ visited the least at 394 per 100 000 (Table 1). Among the 14 LHINs, rates were highest in the North East region, at an average of 882 per 100 000 people per year, and lowest in the Mississauga Halton region, at 148 per 100 000 people per year (Table 2).

Over the nine-year period of observation, there was an approximately 10% increase in overall rate of people visiting EDs for NTDCs (from 359/100 000 in 2006 to 399/100 000 in 2014). As per the Kendal tau correlation test, significant positive trends (figure not presented) in overall rates (r = 0.72, p = 0.0091) and for both men (r = 0.75, p = 0.0064) and women (r = 0.78, p = 0.0049) individually, were observed from 2006 to 2014.

By neighbourhood income quintile, on average, the number of visits made to EDs each year for NTDCs was 2.3 times higher among those living in the lowest neighbourhood income quintile (approximate average 15 856 visits per year) compared to those living in the highest (approximate average 6840 visits per year) (Figure 1). By neighbourhood immigrant tercile, people living in the tercile with the highest immigrant concentration (approximate average 39 759 visits per year) visited approximately nine times more often as those living in neighbourhoods in the tercile with the lowest immigrant concentration (approximate average 4429 visits per year) (Figure 2). By rural/urban stratification, people in rural regions visited EDs for NTDCs almost twice (approximate average 600 people per 100 000 per year) as often as people in urban regions (approximate average 313 people per 100 000 per year) (Figure 3). In terms of trends, the number of visits to EDs for NTDCs consistently increased among all quintiles, terciles and regions, and each trend was statistically significant based on Kendal tau results (correlation and p values are presented in respective figures).

DISCUSSION

We set out to examine trends over time (2006-2014) in ED visits for NTDCs in Ontario, overall and stratified by age, sex, region, and area-level socio-demographic condition (urban/rural, income quintile, and immigrant status). Before this work, only two studies had been completed, which showed the burden on Ontario's health care system due to NTDCs for the years 2003-2006 and 2006-2007. (4,5) Our analysis builds on this research by considering an updated and longer period of observation time.

Our most notable finding is a steady, statistically significant increase in ED visits for NTDCs during this time frame. EDs are an expensive and inefficient option for addressing dental concerns, which would be better addressed in the dental system by dental professionals. (17) However, access to dental care, being inequitable in the Canadian society, can be a possible explanation of these findings. Among OECD countries, Canada fares poorly--including ranking below the United States--in terms of public financing of dental services. (18) In Canada, only approximately 5% of dental care is publicly funded, with jurisdictional variations; provincially, Ontario ranks last, at 1.5%. (19) In this context of limited funding for dental care, our findings speak to a growing burden of health care costs attributed to dental problems.

We also observed large and, in some cases, dramatic discrepancies in ED visits for NTDCs by age and area-level socio-economic indicators. The highest rate of visits was observed in the 0-5 year age group, which is disheartening considering the largely preventable nature of NTDCs and the potential consequences of some NTDCs during childhood for later well-being. (20,21) Though we were not able to compute rates for the area-level stratified analyses, the absolute numbers point to dramatic inequities by neighbourhood income and particularly by immigrant concentrations. Our results corroborate findings of a recent study, where Calvasina et al. showed high unmet dental needs among immigrants in Canada due to low income and lack of dental insurance. (22) We also expect covariation between immigrant and income indicators in our data, but this analysis was not feasible as data obtained were aggregated.

The observation that trends have worsened significantly over time in all groups and are consistently inequitable indicates an important need for both universal and targeted approaches to primary prevention of dental conditions. To enhance equitable access to dental care, policy advocacy is required for publicly funding essential and emergency dental services for all.

Our study has strengths and limitations. The absence of individual-level data on socio-economic circumstances means that misclassification is possible. Due to uncertain denominators, we were unable to compute rates for the stratified analyses with income and immigrant concentrations. Strengths include the ability to access data from the full target population and the high degree of accuracy with which ED visits for NTDCs could be identified.

In terms of future research, similar analyses in other provinces, using consistent methods, would be extremely informative in terms of gauging burden across the country. As a follow-up step, future research should examine: whether rates of ED visits for NTDC vary according to variation in public funding; and changes in rates in response to changes in funding circumstances for dental services. Such analyses would embody a crucial shift in this line of research from the important task of quantifying the extent of the problem, to thinking through potential policy solutions.

doi: 10.17269/CJPH.108.5950

Acknowledgement of Support: Canadian Institute for Health Information for providing data. LM is supported by an Applied Public Health Chair funded by CIHR (Institute of Population & Public Health and Institute of Musculoskeletal Health & Arthritis), the Public Health Agency of Canada, and Alberta Innovates--Health Solutions.

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Received: October 31, 2016

Accepted: March 18, 2017

Sonica Singhal, BDS, MPH, PhD, [1,2] Lindsay McLaren, PhD, [3] Carlos Quinonez, DMD, MSc, PhD [1]

[1.] Dental Public Health, University of Toronto, Toronto, ON

[2.] Health Promotion, Chronic Disease and Injury Prevention Department, Public Health Ontario, Toronto, ON

[3.] Department of Community Health Sciences, University of Calgary, Calgary, AB

Correspondence: Sonica Singhal, PhD, Dental Public Health, University of Toronto, 124 Edward Street, Toronto, ON M5G 1G6, Tel: 647-525-2077, E-mail: sonica. singhal@mail.utoronto.ca

Conflict of Interest: None to declare. Table 1. Nine-year trends of rate of people per 100 000 visiting EDs for NTDCs, stratified by sex and age groups Age groups 2006 2007 2008 2009 (years) F M F M F M F M 0-5 646 742 643 734 653 787 631 796 6-18 214 236 222 251 242 266 245 271 19-64 299 363 319 380 326 386 317 386 65+ 167 206 176 224 182 219 173 215 Overall 332 387 340 397 351 414 342 417 Age groups 2010 2011 2012 2013 2014 (years) F M F M F M F M F M 0-5 645 757 708 800 660 766 665 793 691 797 6-18 235 265 258 285 250 278 257 289 275 289 19-64 326 395 336 399 336 401 334 396 346 399 65+ 174 222 178 218 171 228 171 218 182 216 Overall 345 410 370 425 354 418 357 424 373 425 Table 2. Nine-year trends of rate of people per 100 000 visiting EDs for NTDCs, stratified by LHINs Region 2006 2007 2008 2009 2010 2011 Mississauga Halton 152 137 136 144 147 153 Central 135 139 144 140 149 153 Toronto Central 164 169 173 180 188 199 Central West 165 167 170 172 175 190 Central East 299 310 322 303 313 313 Waterloo Wellington 262 291 277 304 298 316 Hamilton Niagara 336 352 353 327 329 322 Haldimand Brant Champlain 327 338 321 321 321 365 South West 461 502 525 513 509 528 Erie St. Clair 580 613 634 615 614 623 North Simcoe Muskoka 480 541 519 500 533 541 South East 503 543 573 597 616 630 North West 707 780 801 872 938 930 North East 733 747 884 903 877 918 Region 2012 2013 2014 Mississauga Halton 151 149 148 Central 156 161 164 Toronto Central 201 185 187 Central West 198 189 191 Central East 307 306 316 Waterloo Wellington 311 306 324 Hamilton Niagara 339 333 341 Haldimand Brant Champlain 334 350 356 South West 524 508 543 Erie St. Clair 585 576 580 North Simcoe Muskoka 549 621 608 South East 620 614 626 North West 931 910 897 North East 939 953 984 Note: LHINs are arranged from the least to the highest rates, based on 2014 results. Figure 1. Nine-year trends of number of visits made to EDs for NTDCs, stratified by neighbourhood income quintile. * Kendal tau correlations: Quintile 1 (poorest): r = 0.89, p = 0.0012;Quintile 2 (poorer): r = 0.94, p = 0.0006;Quintile 3 (middle): r = 0.83, p = 0.0025;Quintile 4 (richer): r = 0.89, p = 0.0012;Quintile 5 (richest): r = 0.89, p = 0.0012. Quintile 1 Quintile 2 Quintile 3 Quintile 4 Quintile 5 2006 14372 10373 8602 7389 6062 2007 15126 10872 8414 7880 6274 2008 15576 11401 9702 8350 6709 2009 15557 11226 9512 8349 6710 2010 15,792 11,450 9,952 8,809 6,845 2011 16,323 12,169 10,479 9,221 7,135 2012 16,196 12,208 10,452 9,178 7,234 2013 16,761 12,324 10,471 9,482 7,055 2014 16,998 12,494 10,780 9,704 7,538 Note: Table made from line graph. Figure 2. Nine-year trends of number of visits made to EDs for NTDCs, stratified by immigrant tercile. * Kendal tau correlations: Tercile 1: r = 0.89, p = 0.0012;Tercile 2: r = 0.83, p = 0.0025;and Tercile 3: r = 0.83, p = 0.0025. Tercile 1 Tercile 2 Tercile 3 2006 35240 6875 3922 2007 37535 7220 4051 2008 39190 7546 4130 2009 38904 7378 4245 2010 39660 7750 4103 2011 41396 8188 4536 2012 40934 8331 4895 2013 41926 8071 5013 2014 43043 8435 4962 Note: table made from line graph. Figure 3. Nine-year trends of rate of visits per 100 000 people made to EDs for NTDCs, stratified by region: rural/urban. * Kendal tau correlations: rural: r = 0.89, p = 0.012;urban: r = 0.89, p = 0.025. Rural Urban 2006 536 296 2007 555 309 2008 606 311 2009 596 308 2010 603 313 2011 623 322 2012 615 320 2013 620 318 2014 642 323 Note: Table made from line graph.