Phase-Specific Healthcare Costs Associated With Giant Cell Arteritis in Ontario, Canada.

OBJECTIVE: To estimate the additional healthcare system costs associated with giant cell arteritis (GCA) in the 1-year prediagnosis and postdiagnosis periods and over long-term follow-up compared to individuals with similar demographics and comorbidities without GCA. METHODS: We performed a population-based study using health administrative data. Newly diagnosed cases of GCA (between 2002 and 2017 and aged ≥ 66 years) were identified using a validated algorithm and matched 1:6 to comparators using propensity scores. Follow-up data were accrued until death, outmigration, or March 31, 2020. The costs associated with care were determined across 3 phases: the year before the diagnosis of GCA, the year after, and ongoing costs thereafter in 2021 Canadian dollars (CAD). RESULTS: The cohort consisted of 6730 cases of GCA and 40,380 matched non-GCA comparators. The average age was 77 (IQR 72-82) years and 68.2% were female. A diagnosis of GCA was associated with an increased cost of CAD $6619.4 (95% CI 5964.9-7274.0) per patient during the 1-year prediagnostic period, $12,150.3 (95% CI 11,233.1-13,067.6) per patient in the 1-year postdiagnostic phase, and $20,886.2 (95% CI 17,195.2-24,577.2) per patient during ongoing care for year 3 onward. Increased costs were driven by inpatient hospitalizations, physician services, hospital outpatient clinic services, and emergency department visits. CONCLUSION: A diagnosis of GCA was associated with increased healthcare costs during all 3 phases of care. Given the substantial economic burden, strategies to reduce the healthcare utilization and costs associated with GCA are warranted.

Sex-Related Differences in Dispensation of Rheumatic Medications in Older Patients With Inflammatory Arthritis: A Population-Based Study.

OBJECTIVE: The aim of our study was to compare dispensation of rheumatic medications between older male and female patients with early rheumatoid arthritis (RA) and psoriatic arthritis (PsA). METHODS: This retrospective cohort study was performed using health administrative data from Ontario, Canada (years 2010-2017), on patients with incident RA and PsA, who were aged ≥ 66 years at the time of diagnosis. Yearly dispensation of rheumatic drugs was compared between older male and female patients for 3 years after diagnosis using multivariable regression models, after adjusting for confounders. The groups of drugs included in the analysis were disease-modifying antirheumatic drugs (DMARDs) classified as conventional synthetic DMARDs (csDMARDs) and advanced therapy (biologic DMARDs and targeted synthetic DMARDs), nonsteroidal antiinflammatory drugs (NSAIDs), opioids, and oral corticosteroids. Results were reported as odds ratios (ORs) with 95% CIs. RESULTS: We analyzed 13,613 patients (64% female) with RA and 1116 patients (57% female) with PsA. Female patients with RA were more likely to receive opioids (OR 1.39, 95% CI 1.22-1.58 to OR 1.51, 95% CI 1.32-1.72) and NSAIDs (OR 1.14, 95% CI 1.04-1.25 to OR 1.16, 95% CI 1.04-1.30). Dispensation of DMARDs showed no sex difference in either group. Subgroup analyses showed more intense use of advanced therapy in the RA cohort and of csDMARDs in the PsA cohort when patient and physician sex was concordant. CONCLUSION: This study did not identify any sex difference in the use of DMARDs among older patients with RA and PsA. The reasons for the higher use of opioids and NSAIDs among female patients with RA warrant further research.

COVID-19 vaccination safety and associated health care utilization among adults with inflammatory bowel disease - a population-based self-controlled case series analysis.

BACKGROUND AND AIMS: There is an incomplete understanding of the full safety profiles of repeated COVID-19 vaccinations in patients with inflammatory bowel disease (IBD). Among individuals with IBD, we assessed whether COVID-19 vaccines were associated with serious adverse events of special interest (AESI) and health care utilization [all-cause hospitalizations, Emergency Department (ED) visits, gastroenterology visits, IBD-related visits]. METHODS: Using comprehensive administrative health data from Ontario, Canada, adults with IBD who received at least one COVID-19 vaccine from December 2020-January 2022 were included. Self-controlled case series analyses were conducted to evaluate the relative incidence rates of AESI and health care utilization outcomes across post-vaccination risk and control periods. RESULTS: Among 88,407 IBD patients, 99.7% received mRNA vaccines and 75.9% received ≥ 3 doses. Relative to control periods, we did not detect an increase in AESI. IBD patients had fewer all-cause hospitalizations during post-vaccination risk periods. Patients experienced more all-cause ED visits after dose 2 [Relative Incidence (RI):1.08(95%CI:1.04-1.12)] but fewer visits after doses 3 [RI:0.85 (95%CI:0.81-0.90)] and 4 [RI:0.73 (95%CI:0.57-0.92)]. There was no increase in gastroenterologist visits or IBD-related health care utilization post-vaccination. There were fewer IBD-related hospitalizations after dose 1 [RI:0.84 (95%CI:0.72-0.98)] and 3 [RI:0.63 (95%CI:0.52-0.76)], fewer IBD-related ED visits after dose 3 [RI:0.81 (95%CI:0.71-0.91)] and 4 [RI:0.55 (95%CI:0.32-0.96)], and fewer outpatient visits after dose 2 [RI:0.91 (95%CI:0.90-0.93)] and 3 [RI:0.87 (95%CI:0.86-0.89)]. CONCLUSION: This population-based study did not detect increased AESI, all-cause or IBD-related health care utilization following COVID-19 vaccination, suggesting a lack of association between vaccination and increased disease activity.

Early versus late onset interstitial lung disease in rheumatoid arthritis: An observational study of risk factors and mortality in Ontario, Canada.

BACKGROUND AND OBJECTIVE: Interstitial lung disease (ILD) can occur as a manifestation of rheumatoid arthritis (RA) at various times in the disease course. We aimed to identify factors associated with early versus late onset RA-ILD and how the timing of RA-ILD influenced surgical lung biopsy completion and mortality. METHODS: We performed a retrospective observational study using health services data from Ontario, Canada. We identified RA cases between 2000 and 2020 using the Ontario Rheumatoid Arthritis Database. RA-ILD diagnosis required repeat physician visits for ILD, with early RA-ILD defined as within 1 year of RA diagnosis. We performed multivariable logistic regression to identify factors associated with early RA-ILD and surgical lung biopsy completion, and multivariable cox-proportional hazards regression to evaluate the association of early versus late RA-ILD on all-cause and RA-ILD related mortality. RESULTS: In total, we identified 3717 cases of RA-ILD. Older age at RA diagnosis [OR 1.04 (95%CI 1.03-1.05), p < 0.0001], female sex [OR 1.16 (95%CI 1.01-1.35), p = 0.04] and immigrating to Ontario [OR 1.70 (95%CI 1.35-2.14), p < 0.0001] was associated with early RA-ILD. Patients with early versus late RA-ILD experienced similar odds of undergoing a surgical lung biopsy [OR 1.34 (95%CI 0.83-2.16), p = 0.23]. Early RA-ILD was associated with increased all-cause mortality [HR 1.17 (95%CI 1.07-1.29), p = 0.0009], primarily driven by an increase in RA-ILD related mortality [HR 1.45 (95%CI 1.19-1.76), p = 0.0003]. CONCLUSION: Age at RA onset, female sex and immigration status are associated with early RA-ILD. Patients with early RA-ILD experience increased all-cause and RA-ILD related mortality after adjusting for demographics and comorbidities.

Association between immigration status and total knee arthroplasty outcomes in Ontario, Canada: a population-based matched cohort study.

BACKGROUND: Immigrants and refugees face unique challenges navigating the health care system to manage severe arthritis, because of unfamiliarity, lack of awareness of surgical options, or access. The purpose of this study was to assess total knee arthroplasty (TKA) uptake, surgical outcomes, and hospital utilization among immigrants and refugees compared with Canadian-born patients. METHODS: We included all adults undergoing primary TKA from January 2011 to December 2020 in Ontario. Cohorts were defined as Canadian-born or immigrants and refugees. We assessed change in yearly TKA utilization for trend. We compared differences in 1-year revision, infection rates, 30-day venous thromboembolism (VTE), presentation to emergency department, and hospital readmission between matched Canadian-born and immigrant and refugee groups. RESULTS: We included 158 031 TKA procedures. A total of 11 973 (7.6%) patients were in the immigrant and refugee group, and 146 058 (92.4%) patients were in the Canadian-born group. The proportion of TKAs in Ontario performed among immigrants and refugees nearly doubled over the 10-year study period (p < 0.001). After matching, immigrants were at relatively lower risk of 1-year revision (0.9% v. 1.6%, p < 0.001), infection (p < 0.001), death (p = 0.004), and surgical complications (p < 0.001). No differences were observed in rates of 30-day VTE or length of hospital stay. Immigrants were more likely to be discharged to rehabilitation (p < 0.001) and less likely to present to the emergency department (p < 0.001) than Canadian-born patients. CONCLUSION: Compared with Canadian-born patients, immigrants and refugees have favourable surgical outcomes and similar rates of resource utilization after TKA. We observed an underutilization of these procedures in Ontario relative to their proportion of the population. This may reflect differences in perceptions of chronic pain or barriers accessing arthroplasty.

Understanding sex-related differences in healthcare utilisation among patients with inflammatory arthritis: a population-based study.

OBJECTIVES: Our aim was to compare patterns of musculoskeletal-related healthcare utilisation between male and female patients before and after the diagnosis of inflammatory arthritis (IA). METHODS: We used Ontario administrative health data to create three inception cohorts of adult patients with rheumatoid arthritis (RA), ankylosing spondylitis (AS) and psoriatic arthritis (PsA) diagnosed between April 2010 and March 2017. Healthcare utilisation indicators including visits to physicians, and use of musculoskeletal imaging and laboratory tests were assessed in each year for 3 years before and after diagnosis and compared between male and female patients using regression models adjusting for sociodemographic factors and comorbidities. Results were reported as ORs with 95% CIs for female patients compared with male patients. RESULTS: A total of 41 277 patients with RA (69% female), 8150 patients with AS (51% female) and 6446 patients with PsA (54% female) were analysed.Similar trends of sex-related differences were observed in all three cohorts. Before diagnosis, female patients were more likely to visit rheumatologists (OR 1.32-2.28) and family physicians (OR 1.03-1.15) for musculoskeletal reasons, whereas male patients were more likely to visit the emergency for musculoskeletal reasons (OR 0.76-0.87). A similar female predominance was observed regarding musculoskeletal imaging and laboratory tests before diagnosis. After diagnosis, female patients were more likely to remain in rheumatology care (OR 1.12-1.24). CONCLUSION: Female patients with IA have higher healthcare utilisation than male patients which may indicate biological differences in disease course or sociocultural differences in healthcare-seeking behaviour.

Evaluating the time-varying risk of hypertension, cardiac events, and mortality following Kawasaki disease diagnosis.

BACKGROUND: This study evaluated the risk of hypertension, major adverse cardiac events (MACE), and all-cause mortality in Kawasaki disease (KD) patients up to young adulthood. METHODS: An inception cohort of 1169 KD patients between 1991 and 2008 from a tertiary-level hospital in Ontario, Canada was linked with health administrative data to ascertain outcomes up to 28 years of follow-up. Their risk was compared with 11,690 matched population comparators. The primary outcome was hypertension and secondary outcomes were MACE and death. RESULTS: After a median follow-up of 20 years [IQR: 8.3], the cumulative incidence of hypertension and MACE in the KD group was 3.8% (95% CI: 2.5-5.5) and 1.2% (95% CI: 0.6-2.4%), respectively. The overall survival probability in the KD group was 98.6% (95% CI: 97.2-99.3%). Relative to comparators, KD patients were at an increased risk for hypertension [aHR: 2.2 (95% CI: 1.5-3.4)], death [aHR: 2.5 (95% CI: 1.3-5.0)], and MACE [aHR: 10.7 (95% CI: 6.4-17.9)]. For hypertension and MACE, the aHR was the highest following diagnosis and then the excess risk diminished after 16 and 13 years of follow-up, respectively. MACE occurred largely in KD patients with coronary aneurysms [cumulative incidence: 12.8%]. CONCLUSIONS: KD patients demonstrated a reassuring cardiac prognosis up to young adulthood with low events and excellent survival. KD patients were at increased risk for hypertension, but this excess risk occurred early and declined with time. IMPACT: With the current standard of care, KD patients demonstrated favorable cardiac prognosis, with low events of hypertension, MACE, and excellent survival. Hypertension and MACE risk appear to be highest around the time of KD diagnosis. MACE occurred primarily in KD patients with coronary aneurysms. Our findings are reassuring to KD patients, families, and their providers. Our study demonstrated an association between KD exposure and hypertension. This association is relatively novel. Previous studies have remained conflicting if KD contributes to long-term atherosclerotic risk.

Basketball vs. Hockey-The Changing Face of Sport-Related Injuries in Canada.

OBJECTIVE: To characterize and compare the incidence of basketball-related, soccer-related, and hockey-related injuries over a 10-year period. DESIGN: Cohort analysis of sport-related injuries using multiple Ontario healthcare databases. SETTING: Emergency department visits in Ontario, Canada. PATIENTS: Any patient who sustained musculoskeletal injuries sustained while playing basketball, soccer, or hockey between 2006 and 2017 were identified. ASSESSMENT OF RISK FACTORS: Sport of injury, age, sex, rurality index, marginalization status, and comorbidity score. MAIN OUTCOME MEASURES: Annual Incidence Density Rates of injury were calculated for each sport, and significance of trends was analyzed by assessing overlap of 95% confidence intervals. RESULTS: One lakhs eighty five thousand eighty hundred sixty-eight patients (median age: 16 years, interquartile range 13-26) received treatment for sport-related injuries (basketball = 55 468; soccer = 67 021; and hockey = 63 379). The incidence of basketball-related and soccer-related injuries increased from 3.4 (3.3-3.5) to 5.6 (5.5-5.7) and 4.4 (4.3-4.5) to 4.9 (4.8-5) per 10 000 person years, respectively, whereas the incidence of hockey-related injuries decreased from 4.7 (4.6-4.8) to 3.7 (3.6-3.8). Patients with basketball injuries were more marginalized (3.01 ± 0.74) compared with patients with soccer and hockey injuries (2.90 ± 0.75 and 2.72 ± 0.69, respectively). CONCLUSIONS: Accurate regional epidemiologic information regarding sports injuries can be used to guide policy development for municipal planning and sport program development. The trends and demographic patterns described highlight general and sport-specific injury patterns in Ontario. Populations with the highest incidence of injury, most notably adolescents and men older than 50, may represent an appropriate population for injury risk prevention.

Survival after surgery for spinal metastases: a population-based study.

BACKGROUND: There are limited published data on population estimates of survival after spinal surgery for metastatic disease. We performed a population-based study to evaluate survival and complications among patients with cancer who underwent surgery for spinal metastases in Ontario, Canada, between 2006 and 2016. METHODS: We used health administrative databases to identify all patients who underwent surgery for spinal metastases in Ontario between Jan. 1, 2006, and Dec. 31, 2016. We assessed overall survival, mortality rates according to primary cancer lesion and complications after surgery. We contrast the results to those for a comparable cohort from 1991 to 1998. RESULTS: A total of 2646 patients (1194 women [45.1%]; mean age 62.5 yr [standard deviation 12.2 yr]) were identified. The median survival time was 236 (interquartile range 84-740) days. Mortality was highest for patients with melanoma, upper gastrointestinal cancer and lung cancer, with 50% dying within 90 days of surgery. The longest median survival times were observed for primary cancers of the thyroid (906 d) and breast (644 d), and myeloma (830 d). Overall 90-day and 1-year mortality rates were 29% and 59%, respectively. CONCLUSION: We identified differential survivorship based on primary tumour type and a shift in the distribution of operations performed for specific primary cancers over the past 2 decades in Ontario. Overall reductions in mortality associated with this shift in treatment may reflect the use of adjuvant therapies and more personalized treatment approaches.

Trends in mortality and cause-specific mortality among patients with psoriasis and psoriatic arthritis in Ontario, Canada.

BACKGROUND: There is limited information about mortality rates among patients with psoriasis and psoriatic arthritis (PsA) in North America and their change over the past 2 decades. OBJECTIVE: To compare all-cause and cause-specific mortality rates in patients with psoriasis to the general population in Ontario, Canada, from 1996 to 2016. METHODS: We conducted a population-based, retrospective cohort study of adult residents using administrative health data. All-cause and cause-specific standardized mortality rates, standardized mortality ratios, and excess mortality rates were calculated. RESULTS: 176,858 (2,524 deaths) patients with psoriasis and 15,430 (221 deaths) patients with PsA were identified in 2016. Patients with psoriasis and PsA had standardized excess mortality rates of 1.44 and 2.43 per 1000 population, respectively. Standardized mortality rates decreased by approximately 30% over the study period in both disease groups but remained significantly elevated compared to the general population. The leading causes of death in psoriasis and PsA patients were cancer, circulatory disease, and respiratory conditions. LIMITATIONS: We were unable to classify patients according to disease severity. CONCLUSIONS: Despite improvements in psoriasis treatment, the relative excess mortality, which may be related to risk factors for psoriatic disease, remained unchanged, with an average of approximately 1 to 2 extra deaths per 1,000 patients in 2016.

Effects of hospital funding reform on wait times for hip fracture surgery: a population-based interrupted time-series analysis.

BACKGROUND: Health care funding reforms are being used worldwide to improve system performance but may invoke unintended consequences. We assessed the effects of introducing a targeted hospital funding model, based on fixed price and volume, for hip fractures. We hypothesized the policy change was associated with reduction in wait times for hip fracture surgery, increase in wait times for non-hip fracture surgery, and increase in the incidence of after-hours hip fracture surgery. METHODS: This was a population-based, interrupted time series analysis of 49,097 surgeries for hip fractures, 10,474 for ankle fractures, 1,594 for tibial plateau fractures, and 40,898 for appendectomy at all hospitals in Ontario, Canada between April 2012 and March 2017. We used segmented regression analysis of interrupted monthly time series data to evaluate the impact of funding reform enacted April 1, 2014 on wait time for hip fracture repair (from hospital presentation to surgery) and after-hours provision of surgery (occurring between 1700 and 0700 h). To assess potential adverse consequences of the reform, we also evaluated two control procedures, ankle and tibial plateau fracture surgery. Appendectomy served as a non-orthopedic tracer for assessment of secular trends. RESULTS: The difference (95 % confidence interval) between the actual mean wait time and the predicted rate had the policy change not occurred was - 0.46 h (-3.94 h, 3.03 h) for hip fractures, 1.46 h (-3.58 h, 6.50 h) for ankle fractures, -3.22 h (-39.39 h, 32.95 h) for tibial plateau fractures, and 0.33 h (-0.57 h, 1.24 h) for appendectomy (Figure 1; Table 3). The difference (95 % confidence interval) between the actual and predicted percentage of surgeries performed after-hours - 0.90 % (-3.91 %, 2.11 %) for hip fractures, -3.54 % (-11.25 %, 4.16 %) for ankle fractures, 7.09 % (-7.97 %, 22.14 %) for tibial plateau fractures, and 1.07 % (-2.45 %, 4.59 %) for appendectomy. CONCLUSIONS: We found no significant effects of a targeted hospital funding model based on fixed price and volume on wait times or the provision of after-hours surgery. Other approaches for improving hip fracture wait times may be worth pursuing instead of funding reform.

Incidence and prevalence of giant cell arteritis in Ontario, Canada.

OBJECTIVE: To estimate trends in the incidence and prevalence of GCA over time in Canada. METHODS: We performed a population-based study of Ontario health administrative data using validated case definitions for GCA. Among Ontario residents ≥50 years of age we estimated the annual incidence and prevalence rates between 2000 and 2018. We performed sensitivity analyses using alternative validated case definitions to provide comparative estimates. RESULTS: Between 2000 and 2018 there was a relatively stable incidence over time with 25 new cases per 100 000 people >50 years of age. Age-standardized incidence rates were significantly higher among females than males [31 cases (95% CI: 29, 34) vs 15 cases (95% CI: 13, 18) per 100 000 in 2000]. Trends in age-standardized incidence rates were stable among females but increased among males over time. Incidence rates were highest among those ≥70 years of age. Standardized prevalence rates increased from 125 (95% CI 121, 129) to 235 (95% CI 231, 239) cases per 100 000 from 2000 to 2018. The age-standardized rates among males rose from 76 (95% CI 72, 81) cases in 2000 to 156 (95% CI 151, 161) cases per 100 000 population in 2018. Between 2000 and 2018, the age-standardized rates among females similarly increased over time, from 167 (95% CI 161, 173) to 304 (95% CI 297, 310) cases per 100 000 population. CONCLUSION: The incidence and prevalence of GCA in Ontario is similar to that reported in the USA and northern Europe and considerably higher than that reported for southern Europe and non-European populations.

Development and validation of an administrative data algorithm to estimate the disease burden and epidemiology of multiple sclerosis in Ontario, Canada.

BACKGROUND: Few studies have assessed the accuracy of administrative data for identifying multiple sclerosis (MS) patients. OBJECTIVES: To validate administrative data algorithms for MS, and describe the burden and epidemiology over time in Ontario, Canada. METHODS: We employed a validated search strategy to identify all MS patients within electronic medical records, to identify patients with and without MS (reference standard). We then developed and validated different combinations of administrative data for algorithms. The most accurate algorithm was used to estimate the burden and epidemiology of MS over time. RESULTS: The accuracy of the algorithm of one hospitalisation or five physician billings over 2 years provided both high sensitivity (84%) and positive predictive value (86%). Application of this algorithm to provincial data demonstrated an increasing cumulative burden of MS, from 13,326 patients (0.14%) in 2000 to 24,647 patients in 2010 (0.22%). Age-and-sex standardised prevalence increased from 133.9 to 207.3 MS patients per 100,000 persons in the population, from 2000 - 2010. During this same period, age-and-sex-standardised incidence varied from 17.9 to 19.4 patients per 100,000 persons. CONCLUSIONS: MS patients can be accurately identified from administrative data. Our findings illustrated a rising prevalence of MS over time. MS incidence rates also appear to be rising since 2009.

Are family physicians comprehensively using electronic medical records such that the data can be used for secondary purposes? A Canadian perspective.

BACKGROUND: With the introduction and implementation of a variety of government programs and policies to encourage adoption of electronic medical records (EMRs), EMRs are being increasingly adopted in North America. We sought to evaluate the completeness of a variety of EMR fields to determine if family physicians were comprehensively using their EMRs and the suitability of use of the data for secondary purposes in Ontario, Canada. METHODS: We examined EMR data from a convenience sample of family physicians distributed throughout Ontario within the Electronic Medical Record Administrative data Linked Database (EMRALD) as extracted in the summer of 2012. We identified all physicians with at least one year of EMR use. Measures were developed and rates of physician documentation of clinical encounters, electronic prescriptions, laboratory tests, blood pressure and weight, referrals, consultation letters, and all fields in the cumulative patient profile were calculated as a function of physician and patient time since starting on the EMR. RESULTS: Of the 167 physicians with at least one year of EMR use, we identified 186,237 patients. Overall, the fields with the highest level of completeness were for visit documentations and prescriptions (>70%). Improvements were observed with increasing trends of completeness overtime for almost all EMR fields according to increasing physician time on EMR. Assessment of the influence of patient time on EMR demonstrated an increasing likelihood of the population of EMR fields overtime, with the largest improvements occurring between the first and second years. CONCLUSIONS: All of the data fields examined appear to be reasonably complete within the first year of adoption with the biggest increase occurring the first to second year. Using all of the basic functions of the EMR appears to be occurring in the current environment of EMR adoption in Ontario. Thus the data appears to be suitable for secondary use.

Rheumatoid Arthritis Surveillance in Ontario: Monitoring the Burden, Quality of Care and Patient Outcomes through Linkage of Administrative Health Data.

Rheumatoid arthritis (RA) is the most common chronic inflammatory joint disease. Using the Ontario administrative health data housed at the Institute for Clinical Evaluative Sciences, researchers have quantified the population-level burden and epidemiology of RA, mapped its geographic distribution in relation to rheumatologist supply, studied trends in access to rheumatology care and treatment and evaluated patient outcomes. The findings highlight the excess morbidity and mortality associated with the growing burden of RA in the face of a strained rheumatology supply, and raise urgent questions about how best to meet the needs of Ontarians with RA.

An administrative data validation study of the accuracy of algorithms for identifying rheumatoid arthritis: the influence of the reference standard on algorithm performance.

BACKGROUND: We have previously validated administrative data algorithms to identify patients with rheumatoid arthritis (RA) using rheumatology clinic records as the reference standard. Here we reassessed the accuracy of the algorithms using primary care records as the reference standard. METHODS: We performed a retrospective chart abstraction study using a random sample of 7500 adult patients under the care of 83 family physicians contributing to the Electronic Medical Record Administrative data Linked Database (EMRALD) in Ontario, Canada. Using physician-reported diagnoses as the reference standard, we computed and compared the sensitivity, specificity, and predictive values for over 100 administrative data algorithms for RA case ascertainment. RESULTS: We identified 69 patients with RA for a lifetime RA prevalence of 0.9%. All algorithms had excellent specificity (>97%). However, sensitivity varied (75-90%) among physician billing algorithms. Despite the low prevalence of RA, most algorithms had adequate positive predictive value (PPV; 51-83%). The algorithm of "[1 hospitalization RA diagnosis code] or [3 physician RA diagnosis codes with ≥1 by a specialist over 2 years]" had a sensitivity of 78% (95% CI 69-88), specificity of 100% (95% CI 100-100), PPV of 78% (95% CI 69-88) and NPV of 100% (95% CI 100-100). CONCLUSIONS: Administrative data algorithms for detecting RA patients achieved a high degree of accuracy amongst the general population. However, results varied slightly from our previous report, which can be attributed to differences in the reference standards with respect to disease prevalence, spectrum of disease, and type of comparator group.

Fine Particulate Matter Components and Risk of Rheumatoid Arthritis: A Large General Canadian Open Cohort Study.

OBJECTIVE: Exposure to fine particulate matter (PM2.5) has been linked to many diseases. However, it remains unclear which PM2.5 chemical components for these diseases, including rheumatoid arthritis (RA), are more harmful. This study aimed to assess potential associations between PM2.5 components and RA and quantify the individual effects of each chemical component on RA risk. METHODS: An open cohort of 11,696,930 Canadian adults was assembled using Ontario administrative health data from January 2007 onward. Individuals were followed until RA onset, death, emigration from Ontario, or the end of the study (December 2019). Incident RA cases were defined by physician billing and hospitalization discharge diagnostic codes. The average levels of PM2.5 components (ammonium, black carbon, mineral dust, nitrate, organic matter, sea salt, and sulfate) for 5 years before cohort entry were assigned to participants based on residential postal codes. A quantile g-computation and Cox proportional hazard models for time to RA onset were developed for the mixture of PM2.5 components and environmental overall PM2.5, respectively. RESULTS: We identified 67,676 new RA cases across 130,934,256 person-years. The adjusted hazard ratios for the time to RA onset were 1.027 and 1.023 (95% confidence intervals 1.021-1.033 and 1.017-1.029) per every decile increase in exposures to all seven components and per 1 µg/m3 increase in the overall PM2.5, respectively. Ammonium contributed the most to RA onset in the seven components. CONCLUSION: Exposure to PM2.5 components was modestly associated with RA risk. Public health efforts focusing on specific components (eg, ammonium) may be a more efficient way to reduce RA burden.

Adherence and Treat-to-Target Benchmarks in Older Adults With Gout Initiating Urate-Lowering Therapy in Ontario, Canada: A Population-Based Study.

OBJECTIVE: We sought to evaluate urate-lowering therapy (ULT) adherence and treatment-to-target (T2T) serum uric acid (SUA) levels among older adults with gout starting ULT. METHODS: We performed a population-based retrospective cohort study in Ontario, Canada in patients with gout aged ≥66 years newly dispensed ULT between 2010 and 2019. We defined successful T2T as patients having SUA levels <360 µmol/L (6 mg/dL) within 12 months after ULT dispensation. We also assessed adherence to ULT. Multilevel logistic regression clustered by ULT prescriber evaluated patient, physician, and prescription factors associated with reaching target SUA levels. RESULTS: Among 44,438 patients (mean ± SD age 76.0 ± 7.3 years; 64.4% male), 30,057 (67.6%) patients had ≥1 SUA test completed. Overall, 52.3% patients reached SUA target within 12 months, improving from 45.2% in 2010 to 61.2% in 2019 (P < 0.0001). ULT adherence was 55.3% overall and improved annually. Key factors associated with achieving T2T included febuxostat treatment (odds ratio [OR] 11.40, 95% confidence interval [95% CI] 5.10-25.43) (was only dispensed in 88 patients), ULT adherence (OR 5.17, 95% CI 4.89-5.47), allopurinol starting doses >50 mg (OR 2.53, 95% CI 2.14-2.99), colchicine/oral glucocorticoids co-prescription (OR 1.24, 95% CI 1.14-1.34), and ULT prescription from a rheumatologist. CONCLUSION: Only 52.3% of patients achieved an optimal SUA level within 1 year of ULT initiation. ULT adherence was suboptimal, although improving over time. ULT adherence and higher allopurinol starting doses had the strongest associations of achieving a target SUA level. This study highlights room for improvement in gout management and potential strategies to address care gaps.