The Prevalence and Regional Variability of Diabetes among Nursing Home Residents in Ontario.

The prevalence of diabetes mellitus (DM) increases with age and is a major contributor to morbidity and mortality.1, 2 Due to frailty, multiple comorbidities, and functional and cognitive impairment, residents of nursing homes with DM have increased care needs and are at risk of both DM and treatment-related adverse events.2, 3 While the prevalence of DM in nursing homes in Ontario was previously reported at 25% in the early 2000s, DM rates in nursing homes may have increased given the overall increasing rates of DM in the general population.4-6 This study examined the contemporary prevalence of DM among nursing home residents in Ontario, Canada, including regional variations in prevalence and resident characteristics. We conducted a population-based longitudinal descriptive study of nursing home residents in Ontario, Canada, using linked Institute for Clinical Evaluative Sciences (ICES) administrative databases. We identified all nursing home residents between April 1, 2017–March 31, 2022 who were over 66 years of age. Resident characteristics and comorbidities were identified from the Resident Assessment Instrument (RAI) as a part of the Continuing Care Reporting System for Long-Term Care (CCRS-LTC) database. To calculate the prevalence of DM in our cohort, we used the Ontario Diabetes Database (ODD) which is a validated algorithm for identifying DM.7 For each fiscal year between 2017 and 2022, we calculated the prevalence of DM in the entire province and according to geographical regions, based on Ontario Local Health Integration Networks (LHINs). For the most recent fiscal year (April 1, 2021–March 31, 2022), we also measured resident demographic characteristics and comorbidities. We described characteristics of residents overall and compared those with DM to those without using chi-squared test for categorical variables and one-way analysis of variance for continuous variables. The prevalence of DM among nursing home residents in Ontario ranged from 35.5% to 36.7% between 2017 and 2022 (Figure 1, see Supplemental Material Table S1). The prevalence of DM varied geographically, with the highest rates observed in Central West, Central, North East and Toronto Central LHINs where the prevalence of DM ranged from 38.5% to 42.1% (see Supplemental Material Figure S1, Table S2). While the lowest rates were observed in North Simcoe Muskoka, North West and South West LHINs (see Supplemental Material Figure S1, Table S2). As shown in Table 1, nursing home residents with DM were younger than residents without DM (84.1 ± 8.1 vs 85.7 ± 8.3 years, p < 0.001) and the prevalence of DM was higher among men compared to women (42.1% vs 34.2%, p < 0.001). Residents with DM had shorter length of stay in nursing homes (1.74 ± 2.44 vs 2.04 ± 2.73 years, p < 0.001) and a higher proportion were classified as obese based on body mass index (27.1% vs 18.6%, p < 0.001) (Table 1). We report a DM prevalence of 35% to 37% in Ontario nursing homes between 2017 and 2022. This is higher than the previously reported DM prevalence of 25%.4, 5 These rates are in keeping with the increasing overall prevalence of DM among adults, and with recent studies from nursing homes in the United States that have reported DM prevalence of as high as 34%.6, 8, 9 Our study evaluated DM prevalence rates over a 5 year period (which included the years of the COVID-19 pandemic) and did not find any substantial variation in prevalence rates during this time overall or by sex (Figure 1), despite a significant decline in nursing home occupancy likely due to high mortality during the peaks of waves of the pandemic. However, we observed regional variability in the prevalence of DM in Ontario nursing homes that is consistent with higher rates in more central, urban regions which also have higher rates of ethnic diversity (see Supplemental Material Figure S1). Our finding that those with DM were younger and had lower rates of cognitive impairment may be due to individuals with DM having an earlier mortality.10 Residents with DM also had higher BMIs, as they were more frequently in the overweight and obese categories. This is consistent with the expected association between obesity and DM.10 This study demonstrates a higher rate of DM in Ontario nursing home residents than previously reported. Identifying such a high prevalence of DM in nursing homes underscores the importance of rethinking DM management in nursing homes in order to optimize quality of care and redistribute necessary resources accordingly. Armin Farahvash, Lisa M. McCarthy, Wade Thompson, Sho Podolsky, and Iliana C. Lega contributed equally in study design, data analysis, and preparation of the manuscript. This study was supported by ICES, an independent, non-profit research institute funded by an annual grant from the MOH and MLTC. This study was supported by ICES, which is funded by an annual grant from the Ontario Ministry of Health (MOH) and the Ministry of Long-Term Care (MLTC). Parts of this material are based on data and information compiled and provided by: CCRS-LTC, ODD. These datasets were linked using unique encoded identifiers and analyzed at ICES. The analyses, conclusions, opinions, and statements expressed herein are solely those of the authors and do not reflect those of the funding or data sources; no endorsement is intended or should be inferred. This work was supported by the Canadian Institute of Health Research (CIHR) (Grant number: PJT 159472). The authors declare no conflicts of interest. None. Table S1. Prevalence of DM in nursing home residents by sex per year 2017–2022. Table S2. Prevalence of DM in nursing home residents in each LHIN per year 2017–2022. Figure S1. Distribution of DM prevalence across Ontario in long term care residents in 2021 fiscal year. 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