Potential Overtesting of Nursing Home Residents With Diabetes in Ontario, Canada

More than 30% of nursing home residents in North America have diabetes mellitus (DM) [1, 2] and managing DM in this setting is uniquely challenging due to frailty, functional dependence, as well as staffing limitations. No specific guidelines inform the frequency of diabetes monitoring or screening for diabetes-related complications in nursing home residents. While glycated hemoglobin testing (A1c) is recommended every 3–6 months in the general population [3], such testing is likely unnecessary and burdensome for nursing home residents, especially those with stable glycemia or limited life expectancy. The aims of our study were to evaluate rates of diabetes monitoring and screening for dyslipidemia and diabetic microalbuminuria among nursing home residents with diabetes. We conducted a population-based retrospective study using provincial health administrative data from Ontario, Canada, housed at ICES. ICES is an independent, non-profit research institute whose legal status under Ontario's health information privacy law allows it to collect and analyze health care and demographic data without consent for health system evaluation and improvement. Informed consent is not required for this study in accordance with Section 45 of Ontario's Personal Health Information Protection Act. We identified nursing home residents aged ≥ 66 with diabetes between April 1, 2021 and March 31, 2022 based on the Continuing Care Reporting System for Long-Term Care (CCRS-LTC). Diabetes was identified through the validated Ontario Diabetes Database (ODD) [4]. Comorbidities were determined using the CIHI Discharge Abstract Database (DAD) and OHIP billing records. Laboratory data were obtained through the Ontario Laboratories Information System (OLIS), and medication data through the Ontario Drug Benefit (ODB) database. The primary outcome was the frequency and rate of A1c and serum glucose testing over 1 year. Testing rates per person-year were determined for A1c, serum glucose, and lipid testing. We also evaluated the frequency of capillary glucose testing and the use of isCGM. In secondary analyses, we measured the frequency of serum lipid and urine ACR testing. Subgroup analyses were conducted for A1c and serum glucose testing rates by baseline A1c levels, sex, cognitive impairment, and DM medications. Statistical differences were assessed using likelihood ratio tests from univariate Poisson models. ICES is a prescribed entity under Ontario's Personal Health Information Protection Act (PHIPA). Section 45 of PHIPA authorizes ICES to collect personal health information, without consent, for the purpose of analysis or compiling statistical information with respect to the management of, evaluation or monitoring of, the allocation of resources to, or planning for all or part of the health system. Projects that use data collected by ICES under section 45 of PHIPA, and use no other data, are exempt from REB review. The use of the data in this project is authorized under section 45 and approved by ICES' Privacy and Legal Office. Our cohort included 25,005 Ontario nursing home residents (see Table 1 for baseline characteristics). Overall, 81% of residents had at least one A1c test during the one-year period; 46% had ≥ 3 tests. Serum glucose testing occurred in 55% of residents, with 20% receiving ≥ 3 tests (Figure 1a,b). Capillary glucose strips were dispensed to 43% of residents, with 20% receiving ≥ 3/day. isCGM sensors were dispensed to 18% of residents, with 2556 (10.2%) having at least two sensors/month (Figure 1c,d). During follow-up, 7.3% of residents had a urine ACR test and 29% had a serum lipid test (Table S1). In subgroup analyses, A1c testing was more frequent in men, younger residents (< 80 years), those with an A1c > 8.5% and 7.1%–8.5%, and those taking diabetes medications, especially insulin and secretagogues (Table 2). We found similar trends for serum glucose testing in subgroup analyses (Table S2). In this large retrospective study of over 25,000 nursing home residents with diabetes, more than 80% had multiple A1c tests annually, particularly younger residents, men, and those on insulin or sulfonylureas. Our study is the first to assess diabetes testing rates in nursing homes, highlighting potential overtesting and identifying the need to optimize testing practices in this setting. Our finding that 40% of the cohort had more than three A1c tests per year suggests potential unnecessary testing. Notably, A1c testing rates remained high, although statistically lower, even among subgroups where frequent testing may be less necessary—such as residents not taking diabetes medications, those taking medications with a low risk of hypoglycemia, and those with an A1c within the target range (i.e., A1c 7.1%–8.5%). One possible explanation for frequent A1c testing is the absence of specific diabetes testing guidelines for older adults with frailty [5]. Interestingly, this pattern contrasts with the observed low rates of albumin-to-creatinine ratio (ACR) and lipid testing, for which clearer guidance exists, particularly regarding reduced lipid screening for primary prevention in older adults [6]. Given limited resources, minimal benefits, and risk for harms, the need for frequent diabetes testing in nursing homes needs to be carefully addressed through evidence-based, consensus-driven guidelines [7]. Our study also demonstrated that nearly 20% of residents had frequent capillary glucose testing (> 3/day), consistent with prior studies showing high rates even in those on medications at low risk for hypoglycemia [8, 9]. In addition, we report that 10% of residents consistently used an isCGM; while evidence suggests that isCGM may reduce glycemic variability and hypoglycemia risk in these residents, these devices should be used cautiously in this population due to costs, insertion discomfort, legal implications of collected data from sensors, and the risk of further overtesting [10-12]. While isCGM holds promise as a valuable tool for diabetes management in nursing homes, the development of guidelines to inform their optimal use remains necessary [13]. In conclusion, our findings indicate potential overtesting of HbA1c and glucose levels among nursing home residents and underscore the need for tailored diabetes monitoring strategies to ensure appropriate and effective care in this population. All authors contributed to the conception and design of the study. ICES conducted data collection and statistical analysis. Youssef El-Sayes and Iliana Lega prepared the first draft of the manuscript. All authors reviewed, edited, and approved the final version of the manuscript for submission. Iliana Lega is the guarantor of this work and, as such, had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. 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). This study received funding from: The Canadian Institutes of Health Research (CIHR) (Grant number: PJT-159472). We thank IQVIA Solutions Canada Inc. for the use of their Drug Information File. Parts of this material are based on data and/or information compiled and provided by CIHI, MOH, MLTC. 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. The authors declare no conflicts of interest. Table S1: Frequency of testing in LTC residents with DM over a 1-year period. Table S2: Rates of serum glucose testing by subgroup. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.