Validating use of diagnostic codes in Canadian administrative data for identification of adverse drug events.

AIMS: While diagnostic codes from administrative health data might be a valuable source to identify adverse drug events (ADEs), their ability to identify unintended harms remains unclear. We validated claims-based diagnosis codes for ADEs based on events identified in a prospective cohort study and assessed whether key attributes predicted their documentation in administrative data. METHODS: This was a retrospective analysis of 3 prospective cohorts in British Columbia, from 2008 to 2015 (n = 13 969). We linked prospectively identified ADEs to administrative insurance data to examine the sensitivity and specificity of different diagnostic code schemes. We used logistic regression to assess which key attributes (e.g., type of event, symptoms and culprit medications) were associated with better documentation of ADEs in administrative data. RESULTS: Among 1178 diagnosed events, the sensitivity of the diagnostic codes in administrative data ranged from 3.4 to 52.6%, depending on the database and codes used. We found that documentation was worse for certain types of ADEs (dose-related: odds ratio [OR]: 0.32, 95% confidence interval [CI]: 0.15, 0.69; nonadherence events (OR: 0.35, 95% CI: 0.20, 0.62), and better for those experiencing arrhythmias (OR: 4.19, 95% CI: 0.96, 18.28). CONCLUSION: ADEs were not well documented in administrative data. Alternative methods should be explored to capture ADEs for health research.

Prescriptions for Antipsychotics: Youth with Intellectual/Developmental Disabilities Compared to Youth without Intellectual/Developmental Disabilities.

PURPOSE: The purpose of this study was to compare antipsychotic use by youth with intellectual/developmental disabilities to youth without IDD as they transitioned from pediatric to adult health care services. In addition, antipsychotic use was compared between youth with different types of IDD (autism, Fetal Alcohol Syndrome, Down syndrome and 'other'). METHODS: Population level administrative health data was used to compare the dispensing of antipsychotics for youth aged 15 to 24 years with and without IDD, between 2010 and 2019. Because antipsychotics are associated with metabolic syndrome and type 2 diabetes, we also examined the dispensing data for metformin. In addition, we examined dispensed antipsychotics between different types of IDD. For both dispensing of antipsychotics and metformin, we used multi-variable logistic regression to derive adjusted odds ratios. RESULTS: There were 20,591 youth with IDD and 1,293,791 youth without IDD. Youth with IDD had significantly higher odds of being dispensed an antipsychotic (7.13 (6.82, 7.44)), even when a diagnosis of a psychotic illness was included in the regression. Higher odds were found in all age groups. Youth with IDD also had significantly higher odds of being dispensed metformin (3.739 (3.323, 4.208)) compared to youth without IDD. Youth with autism, FAS and 'other' types of IDD diagnoses all had higher odds of being dispensed an antipsychotic compared to youth with Down syndrome. CONCLUSION: Compared to youth without IDD, youth with IDD were more frequently dispensed antipsychotics and metformin. These findings have important implications for the health of youth with IDD.

Validating methods used to identify non-adherence adverse drug events in Canadian administrative health data.

AIMS: Medication non-adherence is a type of adverse drug event that can lead to untreated and exacerbated chronic illness, and that drives healthcare utilization. Research using medication claims data has attempted to identify instances of medication non-adherence using the proportion of days covered or by examining gaps between medication refills. We sought to validate these measures compared to a gold standard diagnosis of non-adherence made in hospital. METHODS: This was a retrospective analysis of adverse drug events diagnosed during three prospective cohorts in British Columbia between 2008 and 2015 (n = 976). We linked prospectively identified adverse drug events to medication claims data to examine the sensitivity and specificity of typical non-adherence measures. RESULTS: The sensitivity of the non-adherence measures ranged from 22.4% to 37.5%, with a proportion of days covered threshold of 95% performing the best; the non-persistence measures had sensitivities ranging from 10.4% to 58.3%. While a 7-day gap was most sensitive, it classified 61.2% of the sample as non-adherent, whereas only 19.6% were diagnosed as such in hospital. CONCLUSIONS: The methods used to identify non-adherence in administrative databases are not accurate when compared to a gold standard diagnosis by healthcare providers. Research that has relied on administrative data to identify non-adherent patients both underestimates the magnitude of the problem and may label patients as non-adherent who were in fact adherent.

Population Level Mental Health Diagnoses for Youth with Intellectual/Developmental Disabilities Compared to Youth without Intellectual/Developmental Disabilities.

There is evidence in the literature that youth with intellectual/developmental disabilities (IDD) experience mental health issues to a greater extent compared to youth without IDD. In addition, transition from pediatric to adult services may be a period of increased anxiety and mental health problems for these youth. This study used a retrospective cohort design using population level administrative health data to compare mental health diagnoses between youth with IDD and youth without IDD; particularly examining the period when youth transition from pediatric health services to adult health services. In addition, this study compared the mental health of youth with various types of IDD (Down syndrome, autism, fetal alcohol syndrome and other rarer diagnoses). Results showed that at the population level youth with IDD have greater odds of anxiety/depression or psychotic illness than youth without IDD. Adjusted odds of anxiety/depression or psychotic illness also varied with age, income level, sex, and type of IDD. Youth with fetal alcohol syndrome had the greatest odds of both anxiety/depression and a psychotic illness. Odds of anxiety/depression increased from age 15-19 years old. Odds of a psychotic illness increased from age 15 to age 24 years old.

Changes in comprehensiveness of services delivered by Canadian family physicians: Analysis of population-based linked data in 4 provinces.

OBJECTIVE: To describe changes in the comprehensiveness of services delivered by family physicians across service settings and service areas in 4 Canadian provinces, to identify which settings and areas have changed the most, and to compare the magnitude of changes by physician characteristics. DESIGN: Descriptive analysis of province-wide, population-based billing data linked to population and physician registries. SETTING: British Columbia, Manitoba, Ontario, and Nova Scotia. PARTICIPANTS: Family physicians registered to practise in the 1999-2000 and 2017-2018 fiscal years. MAIN OUTCOME MEASURES: Comprehensiveness was measured across 7 service settings (home care, long-term care, emergency departments, hospitals, obstetric care, surgical assistance, anesthesiology) and in 7 service areas consistent with office-based practice (prenatal and postnatal care, Papanicolaou testing, mental health, substance use, cancer care, minor surgery, palliative home visits). The proportion of physicians with activity in each setting and area are reported and the average number of service settings and areas by physician characteristics is described (years in practice, sex, urban or rural practice setting, and location of medical degree training). RESULTS: Declines in comprehensiveness were observed across all provinces studied. Declines were greater for comprehensiveness of settings than for areas consistent with office-based practice. Changes were observed across all physician characteristics. On average across provinces, declines in the number of service settings and service areas were highest among physicians in practice 20 years or longer, male physicians, and physicians practising in urban areas. CONCLUSION: Declining comprehensiveness was observed across all physician characteristics, pointing to changes in the practice and policy contexts in which all family physicians work.

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

INTRODUCTION: The literature indicates that youth with intellectual/developmental disabilities (IDD), such as Down syndrome or autism, have poor oral health. A number of factors influence their oral health, including the use of medically required dental treatments. METHODS: This paper describes the first use of population-level administrative health data to examine the use of medically required dental services by youth with IDD compared with youth without IDD in Canada. RESULTS: Youth with IDD had 4-9 times the odds of a medically required dental treatment compared with youth without IDD. Odds varied with age and type of IDD. CONCLUSIONS: Youth with IDD used medically required dental services to a greater extent than youth without IDD. Use of medically required dental treatments by youth with IDD declined with age; this may indicate greater difficulty accessing services when youth transition from pediatric to adult services. These findings provide baseline information on the use of medically required dental treatments and can contribute to future assessments of dental services for youth with IDD.

Population-level use of gynecological health services by female youth with intellectual/developmental disabilities in British Columbia Canada.

BACKGROUND: There is evidence that female youth with intellectual/developmental disabilities (IDD) experience poorer gynecological care compared to female youth without disabilities. OBJECTIVE: The objective of this study was to obtain baseline data on visits to a health care provider for a gynecological issue for females with IDD and compare that information to the experiences of female youth without IDD. METHODS: This study is a retrospective cohort study using population-level administrative health data from 2010 to 2019 for females aged 15-24 years, with and without IDD. RESULTS: 6452 female youth with IDD and 637,627 female youth without IDD were identified in the data. Over the ten-year period, 53.77% of youth with IDD and 53.68% of youth without IDD had a visit to a physician for a gynecological issue. However, as females with IDD aged, the number of people seeing a physician for a gynecological issue decreased. In the group aged 20-24 years, 15.25% of females with IDD and 24.47% of females without IDD (p < 0.0001) had a Pap test done at any time; 25.94% of females with IDD had a visit for contraception management and 28.38% of females (p < 0.0001) without IDD had a visit for contraception management. Gynecological care also varied by type of IDD. CONCLUSIONS: Females with IDD had a similar number of visits for a gynecological issue as female youth without IDD. However, the reasons for visits and the age at which visits occurred differed between youth with and without IDD. As females with IDD transition into adulthood, gynecological care must be maintained and improved.

Population level administrative data evidence of visits to the emergency department by youth with intellectual/developmental disabilities in BC, Canada.

INTRODUCTION: The literature indicates that youth with intellectual/developmental disabilities (IDD) have poor health and that access to health services decreases as they transition from pediatric to adult services. At the same time their use of emergency department services increases. The objective of this study was to compare use of emergency department services by youth with IDD to youth without IDD, with particular emphasis on the transition period from pediatric to adult health care services. METHODS: This research used a population level administrative health data base for the province of British Columbia Canada for 2010-2019 to examine the use of emergency departments by youth with IDD (N = 20,591) compared to a population group of youth without IDD (N = 1,293,791). Using the ten years of data, odds ratios for visits to the emergency department were calculated adjusting for sex, income and geographical area within the Province. In addition, difference-in-differences analyses were calculated for age matched subsets of the two cohorts. RESULTS: Over the ten year period, 40.60% of youth with IDD visited an emergency department at least once, compared to 29.10% of youth without IDD. Youth with IDD had an odds ratio of visiting an emergency department 1.697 (1.649, 1.747) times that of youth without IDD. However, when odds were adjusted for a diagnosis of either psychotic illness or anxiety/depression, the odds for youth with IDD visiting emergency compared to youth without IDD were reduced to 1.063 (1.031, 1.096). Use of emergency services increased as youth aged. Type of IDD also affected use of emergency services. Youth with Fetal Alcohol Syndrome had the greatest odds of using emergency services compared to youth with other types of IDD. DISCUSSION: The findings from this study indicate that youth with IDD have higher odds of using emergency services than youth without IDD although these increased odds appear to be largely driven by mental illness. In addition, use of emergency services increases as the youth age and transition from pediatric to adult health services. Better treatment of mental health issues within this population may reduce their use of emergency services.

Declining Comprehensiveness of Services Delivered by Canadian Family Physicians Is Not Driven by Early-Career Physicians.

We describe changes in the comprehensiveness of services delivered by family physicians in 4 Canadian provinces (British Columbia, Manitoba, Ontario, Nova Scotia) during the periods 1999-2000 and 2017-2018 and explore if changes differ by years in practice. We measured comprehensiveness using province-wide billing data across 7 settings (home, long-term care, emergency department, hospital, obstetrics, surgical assistance, anesthesiology) and 7 service areas (pre/postnatal care, Papanicolaou [Pap] testing, mental health, substance use, cancer care, minor surgery, palliative home visits). Comprehensiveness declined in all provinces, with greater changes in number of service settings than service areas. Decreases were no greater among new-to-practice physicians.

Coping Behaviors and Health Status during the COVID-19 Pandemic among Caregivers of Assisted Living Residents in Western Canada.

OBJECTIVES: To examine the prevalence of coping behaviors during the first 2 waves of the COVID-19 pandemic among caregivers of assisted living residents and variation in these behaviors by caregiver gender and mental health. DESIGN: Cross-sectional and longitudinal survey. SETTING AND PARTICIPANTS: Family/friend caregivers of assisted living residents in Alberta and British Columbia. METHODS: A web-based survey, conducted twice (October 28, 2020 to March 31, 2021 and July 12, 2021 to September 7, 2021) on the same cohort obtained data on caregiver sociodemographic characteristics, anxiety and depressive symptoms, and coping behaviors [seeking counselling, starting a psychotropic drug (sedative, anxiolytic, antidepressant), starting or increasing alcohol, tobacco and/or cannabis consumption] during pandemic waves 1 and 2. Descriptive analyses and multivariable (modified) Poisson regression models identified caregiver correlates of each coping behavior. RESULTS: Among the 673 caregivers surveyed at baseline, most were women (77%), White (90%) and age ≥55 years (81%). Alcohol (16.5%) and psychotropic drug (13.3%) use were the most prevalent coping behaviors reported during the initial wave, followed by smoking and/or cannabis use (8.0%), and counseling (7.4%). Among the longitudinal sample (n = 386), only alcohol use showed a significantly lower prevalence during the second wave (11.7% vs 15.1%, P = .02). During both waves, coping behaviors did not vary significantly by gender, however, psychotropic drug and substance use were significantly more prevalent among caregivers with baseline anxiety and depressive symptoms, including in models adjusted for confounders [eg, anxiety: adjusted risk ratio = 3.87 (95% CI 2.50-6.00] for psychotropic use, 1.87 (1.28-2.73) for alcohol use, 2.21 (1.26-3.88) for smoking/cannabis use). CONCLUSIONS AND IMPLICATIONS: Assisted living caregivers experiencing anxiety or depressive symptoms during the pandemic were more likely to engage in drug and substance use, potentially maladaptive responses. Public health and assisted living home initiatives that identify caregiver mental health needs and provide targeted support during crises are required to mitigate declines in their health.

Stage-Specific Risk of Breast Cancer among Canadian Immigrant and Non-Immigrant Women.

BACKGROUND: Breast cancer screening utilization varies across immigrant and non-immigrant populations. Recent studies have also suggested that some immigrant populations in Canada present with a higher frequency of later-stage breast cancer compared to non-immigrants. Our study aimed to augment prior research by presenting breast cancer stage distributions and stage-specific breast cancer incidence rates for immigrant and non-immigrants in British Columbia, Canada. METHODS: We utilized a population-based cohort of more than 1.3 million women built from linked administrative health and immigration data sets. Age-standardized incidence rate ratios were generated to compare immigrant and non-immigrant groups. Poisson regression was used to assess the relative frequency of later stage diagnosis among immigrant groups compared to non-immigrants. RESULTS: Indian and Chinese immigrants both showed significantly lower stage I and stage II-IV incidence rates compared to non-immigrants. However, Indian immigrants showed a higher frequency of later stage tumours at diagnosis compared to non-immigrants, while in contrast Chinese immigrants showed a lower frequency of later stage tumours. Filipino immigrants showed similar stage-specific rates and stage at diagnosis compared to non-immigrants. CONCLUSIONS: Our findings highlight a need for continued surveillance of cancer among immigrant and non-immigrant populations and inquiry into reasons for differences in stage at diagnosis across groups.

Caregivers' Concerns About Assisted Living Residents' Mental Health During the COVID-19 Pandemic: A Cross-Sectional Survey Study.

Family or friend caregivers' concerns about assisted living (AL) residents' mental health are reflective of poor resident and caregiver mental health. COVID-19-related visiting restrictions increased caregiver concerns, but research on these issues in AL is limited. Using web-based surveys with 673 caregivers of AL residents in Western Canada, we assessed the prevalence and correlates of moderate to severe caregiver concerns about residents' depressed mood, loneliness, and anxiety in the 3 months before and after the start of the COVID-19 pandemic. Caregiver concerns doubled after the start of the pandemic (resident depressed mood: 23%-50%, loneliness: 29%-62%, anxiety: 24%-47%). Generalized linear mixed models identified various modifiable risk factors for caregiver concerns (e.g., caregivers' perception that residents lacked access to counseling services or not feeling well informed about and involved in resident care). These modifiable factors can be targeted in efforts to prevent or mitigate caregiver concerns and resident mental health issues.

Initial health care costs for COVID-19 in British Columbia and Ontario, Canada: an interprovincial population-based cohort study.

BACKGROUND: COVID-19 imposed substantial health and economic burdens. Comprehensive population-based estimates of health care costs for COVID-19 are essential for planning and policy evaluation. We estimated publicly funded health care costs in 2 Canadian provinces during the pandemic's first wave. METHODS: In this historical cohort study, we linked patients with their first positive SARS-CoV-2 test result by June 30, 2020, in 2 Canadian provinces (British Columbia and Ontario) to health care administrative databases and matched to negative or untested controls. We stratified patients by highest level of initial care: community, long-term care, hospital (without admission to the intensive care unit [ICU]) and ICU. Mean publicly funded health care costs for patients and controls, mean net (attributable to COVID-19) costs and total costs were estimated from 30 days before to 120 days after the index date, or to July 31, 2020, in 30-day periods for patients still being followed by the start of each period. RESULTS: We identified 2465 matched people with a positive test result for SARS-CoV-2 in BC and 28 893 in Ontario. Mean age was 53.4 (standard deviation [SD] 21.8) years (BC) and 53.7 (SD 22.7) years (Ontario); 55.7% (BC) and 56.1% (Ontario) were female. Net costs in the first 30 days after the index date were $22 010 (95% confidence interval [CI] 19 512 to 24 509) and $15 750 (95% CI 15 354 to 16 147) for patients admitted to hospital, and $65 828 (95% CI 58 535 to 73 122) and $56 088 (95% CI 53 721 to 58 455) for ICU patients in BC and Ontario, respectively. In the community and long-term care settings, net costs were near 0. Total costs for all people, from 30 days before to 30 days after the index date, were $22 128 330 (BC) and $175 778 210 (Ontario). INTERPRETATION: During the first wave, we found that mean costs attributable to COVID-19 were highest for patients with ICU admission and higher in BC than Ontario. Reducing the number of people who acquire COVID-19 and severity of illness are required to mitigate the economic impact of COVID-19.

Prevalence and correlates of anxiety and depression in caregivers to assisted living residents during COVID-19: a cross-sectional study.

BACKGROUND: Family and friend caregivers play significant roles in advocating for and ensuring quality health and social care of residents in Assisted Living (AL) homes. However, little is known about how the COVID-19 pandemic and related visitor restrictions affected their health and mental well-being. We examined the prevalence and correlates of anxiety and depressive symptoms among caregivers of AL residents during the initial wave of COVID-19 in two Canadian provinces. METHODS: A cross-sectional web-based survey was conducted among family/friend caregivers of AL residents in Alberta and British Columbia (Oct 28, 2020-Mar 31, 2021) to collect data on their sociodemographic, health and caregiving characteristics, as well as concerns about residents' health and social care before and during the first wave of the pandemic. A clinically significant anxiety disorder and depressive symptoms were assessed with the GAD-7 and CES-D10 instruments, respectively. Separate multivariable (modified) Poisson regression models identified caregiver correlates of each mental health condition. RESULTS: Among the 673 caregivers completing the survey (81% for Alberta residents), most were women (77%), white (90%) and aged ≥ 55 years (81%). Clinically significant anxiety and depression were present in 28.6% and 38.8% of caregivers respectively. Both personal stressors (comorbidity level, income reduction, low social support) and caregiving stressors exacerbated by the pandemic were independently associated with caregiver anxiety and depression. The latter included increased concern about the care recipients' depression (adjusted risk ratio [adjRR] = 1.84, 95% confidence interval [CI] 1.19-2.85 for caregiver anxiety and adjRR = 1.75, 95% CI 1.26-2.44 for caregiver depressive symptoms) and reported intention to withdraw the resident from AL because of COVID-19 (adjRR = 1.24, 95%CI 0.95-1.63 for caregiver anxiety and adjRR = 1.37, 95%CI 1.13-1.67 for caregiver depressive symptoms). CONCLUSIONS: Caregivers of residents in AL homes reported significant personal and caregiving-related stressors during the initial wave of COVID-19 that were independently associated with an increased likelihood of experiencing clinically significant anxiety and depressive symptoms. Healthcare providers and AL staff should be aware of the prevalence and varied correlates of caregivers' mental health during public health crises so that appropriate screening and support may identified and implemented.

Characterizing people with frequent emergency department visits and substance use: a retrospective cohort study of linked administrative data in Ontario, Alberta, and B.C., Canada.

BACKGROUND: Substance use is common among people who visit emergency departments (EDs) frequently. We aimed to characterize subgroups within this cohort to better understand care needs/gaps, and generalizability of characteristics in three Canadian provinces. METHODS: This was a retrospective cohort study (April 1st, 2013 to March 31st, 2016) of ED patients in Ontario, Alberta, and British Columbia (B.C.) We included patients ≥ 18 years with substance use-related healthcare contact during the study period and frequent ED visits, defined as those in the top 10% of ED utilization when all patients were ordered by annual ED visit number. We used linked administrative databases including ED visits and hospitalizations (all provinces); mental heath-related hospitalizations (Ontario and Alberta); and prescriptions, physician services, and mortality (B.C.). We compared to cohorts of people with (1) frequent ED visits and no substance use, and (2) non-frequent ED visits and substance use. We employed cluster analysis to identify subgroups with distinct visit patterns and clinical characteristics during index year, April 1st, 2014 to March 31st, 2015. RESULTS: In 2014/15, we identified 19,604, 7,706, and 9,404 people with frequent ED visits and substance use in Ontario, Alberta, and B.C (median 37-43 years; 60.9-63.0% male), whose ED visits and hospitalizations were higher than comparison groups. In all provinces, cluster analyses identified subgroups with "extreme" and "moderate" frequent visits (median 13-19 versus 4-6 visits/year). "Extreme" versus "moderate" subgroups had more hospitalizations, mental health-related ED visits, general practitioner visits but less continuity with one provider, more commonly left against medical advice, and had higher 365-day mortality in B.C. (9.3% versus 6.6%; versus 10.4% among people with frequent ED visits and no substance use, and 4.3% among people with non-frequent ED visits and substance use). The most common ED diagnosis was acute alcohol intoxication in all subgroups. CONCLUSIONS: Subgroups of people with "extreme" (13-19 visits/year) and "moderate" (4-6 visits/year) frequent ED visits and substance use had similar utilization patterns and characteristics in Ontario, Alberta, and B.C., and the "extreme" subgroup had high mortality. Our findings suggest a need for improved evidence-based substance use disorder management, and strengthened continuity with primary and mental healthcare.

People who make frequent emergency department visits based on persistence of frequent use in Ontario and Alberta: a retrospective cohort study.

BACKGROUND: The factors that underlie persistent frequent visits to the emergency department are poorly understood. This study aimed to characterize people who visit emergency departments frequently in Ontario and Alberta, by number of years of frequent use. METHODS: This was a retrospective cohort study aimed at capturing information about patients visiting emergency departments in Ontario and Alberta, Canada, from Apr. 1, 2011, to Mar. 31, 2016. We identified people 18 years or older with frequent emergency department use (top 10% of emergency department use) in fiscal year 2015/16, using the Dynamic Cohort from the Canadian Institute of Health Information. We then organized them into subgroups based on the number of years (1 to 5) in which they met the threshold for frequent use over the study period. We characterized subgroups using linked emergency department, hospitalization and mental health-related hospitalization data. RESULTS: We identified 252 737 people in Ontario and 63 238 people in Alberta who made frequent visits to the emergency department. In Ontario and Alberta, 44.3% and 44.7%, respectively, met the threshold for frequent use in only 1 year and made 37.9% and 38.5% of visits; 6.8% and 8.2% met the threshold for frequent use over 5 years and made 11.9% and 13.2% of visits. Many characteristics followed gradients based on persistence of frequent use: as years of frequent visits increased (1 to 5 years), people had more comorbidities, homelessness, rural residence, annual emergency department visits, alcohol- and substance use-related presentations, mental health hospitalizations and instances of leaving hospital against medical advice. INTERPRETATION: Higher levels of comorbidities, mental health issues, substance use and rural residence were seen with increasing years of frequent emergency department use. Interventions upstream and in the emergency department must address unmet needs, including services for substance use and social supports.

Subgroups of people who make frequent emergency department visits in Ontario and Alberta: a retrospective cohort study.

BACKGROUND: The population that visits emergency departments frequently is heterogeneous and at high risk for mortality. This study aimed to characterize these patients in Ontario and Alberta, compare them with controls who do not visit emergency departments frequently, and identify subgroups. METHODS: This was a retrospective cohort study that captured patients in Ontario or Alberta from fiscal years 2011/12 to 2015/16 in the Dynamic Cohort from the Canadian Institute for Health Information, which defined people with frequent visits to the emergency department in the top 10% of annual visits and randomly selected controls from the bottom 90%. We included patients 18 years of age or older and linked to emergency department, hospitalization, continuing care, home care and mental health-related hospitalization data. We characterized people who made frequent visits to the emergency department over time, compared them with controls and identified subgroups using cluster analysis. We examined emergency department visit acuity using the Canadian Triage and Acuity Scale. RESULTS: The number of patients who made frequent visits to the emergency department ranged from 435 334 to 477 647 each year in Ontario (≥ 4 visits per year), and from 98 840 to 105 047 in Alberta (≥ 5 visits per year). The acuity of these visits increased over time. Those who made frequent visits to the emergency department were older and used more health care services than controls. We identified 4 subgroups of those who made frequent visits: "short duration" (frequent, regularly spaced visits), "older patients" (median ages 69 and 64 years in Ontario and Alberta, respectively; more comorbidities; and more admissions), "young mental health" (median ages 45 and 40 years in Ontario and Alberta, respectively; and common mental health-related and alcohol-related visits) and "injury" (increased prevalence of injury-related visits). INTERPRETATION: From 2011/12 to 2015/16, people who visited emergency departments frequently had increasing visit acuity, had higher health care use than controls, and comprised distinct subgroups. Emergency departments should codevelop interventions with the identified subgroups to address patient needs.

How long does it take patients to find a new primary care physician when theirs retires: a population-based, longitudinal study.

BACKGROUND: The retirement of a family physician can represent a challenge in accessibility and continuity of care for patients. In this population-based, longitudinal cohort study, we assess whether and how long it takes for patients to find a new majority source of primary care (MSOC) when theirs retires, and we investigate the effect of demographic and clinical characteristics on this process. METHODS: We used provincial health insurance records to identify the complete cohort of patients whose majority source of care left clinical practice in either 2007/2008 or 2008/2009 and then calculated the number of days between their last visit with their original MSOC and their first visit with their new one. We compared the clinical and sociodemographic characteristics of patients who did and did not find a new MSOC in the three years following their original physician's retirement using Chi-square and Fisher's exact test. We also used Cox proportional hazards models to determine the adjusted association between patient age, sex, socioeconomic status, location and morbidity level (measured using Johns Hopkins' Aggregated Diagnostic Groupings), and time to finding a new primary care physician. We produce survival curves stratified by patient age, sex, income and morbidity. RESULTS: Fifty-four percent of patients found a new MSOC within the first 12 months following their physician's retirement. Six percent of patients still had not found a new physician after 36 months. Patients who were older and had higher levels of morbidity were more likely to find a new MSOC and found one faster than younger, healthier patients. Patients located in more urban regional health authorities also took longer to find a new MSOC compared to those in rural areas. CONCLUSIONS: Primary care physician retirements represent a potential threat to accessibility; patients followed in this study took more than a year on average to find a new MSOC after their physician retired. Providing programmatic support to retiring physicians and their patients, as well as addressing shortages of longitudinal primary care more broadly could help to ensure smoother retirement transitions.

Characteristics of frequent emergency department users in British Columbia, Canada: a retrospective analysis.

BACKGROUND: Frequent emergency department users disproportionately account for rising health care costs. We aimed to characterize frequent emergency department users in British Columbia, Canada. METHODS: We performed a retrospective analysis using health administrative databases. We included patients aged 18 years or more with at least 1 emergency department visit from 2012/13 to 2015/16, linked to hospital, physician billing, prescription and mortality data. We used annual emergency department visits made by the top 10% of patients to define frequent users (≥ 3 visits/year). RESULTS: Over the study period, 13.8%-15.3% of patients seen in emergency departments were frequent users. We identified 205 136 frequent users among 1 196 353 emergency department visitors. Frequent users made 40.3% of total visits in 2015/16. From 2012/13 to 2015/16, their visit rates per 100 000 BC population showed a relative increase of 21.8%, versus 13.1% among all emergency department patients. Only 1.8% were frequent users in all study years. Mental illness accounted for 8.2% of visits among those less than 60 years of age, and circulatory or respiratory diagnoses for 13.3% of visits among those aged 60 or more. In 2015/16, frequent users were older and had lower household incomes than nonfrequent users; the sex distribution was similar. Frequent users had more prescriptions (median 9, interquartile range [IQR] 5-14 v. 1, IQR 1-3), primary care visits (median 15, IQR 9-27 v. 7, IQR 4-12) and hospital admissions (median 2, IQR 1-3 v. 1, IQR 1-1), and higher 1-year mortality (10.2% v. 3.5%) than nonfrequent users. INTERPRETATION: Emergency department use by frequent users increased in BC between 2012/13 and 2015/16; these patients were heterogenous, had high mortality and rarely remained frequent users over multiple years. Our results suggest that interventions must account for heterogeneity and address triggers of frequent use episodes.

The impact of public coverage of newer hepatitis C medications on utilization, adherence, and costs in British Columbia.

BACKGROUND: Sofosbuvir and ledipasvir-sofosbuvir are both newer direct-acting antiviral agents for the treatment of hepatitis C. The high list prices for both drugs have led to concern about the budget impact for public drug coverage programs. Therefore, we studied the impact of public prescription drug coverage for both drugs on utilization, adherence, and public and private expenditure in British Columbia, Canada. METHODS: We used provincial administrative claims data from January 2014 to June 2017 for all individuals historically tested for either hepatitis C and/or human immunodeficiency virus. Using interrupted time series analysis, we examined the impact of public insurance coverage on treatment uptake, adherence (proportion of days covered), and public and private expenditures. RESULTS: Over our study period, 4,462 treatment initiations were eligible for analysis (1,131 sofosbuvir and 3,331 ledipasvir-sofosbuvir, which include 19 patients initiated on both treatments). We found the start of public coverage for sofosbuvir and ledipasvir-sofosbuvir increased treatment uptake by 154%. Adherence rates were consistently high and did not change with public coverage. Finally, public expenditure increased after the policy change, and crowded out some private expenditure. CONCLUSION: Public coverage for high-cost drugs for hepatitis C dramatically increased use of these drugs, but did not reduce adherence. From a health policy perspective, public payers should be prepared for increased treatment uptake following the availability of public coverage. However, they should not be concerned that populations without private insurance coverage will be less adherent and not finish their treatment course.