Michael Paterson - Academia.edu (original) (raw)

Papers by Michael Paterson

Journal of Neuromuscular Diseases, 2021

Background: Prednisone is a common treatment for myasthenia gravis (MG), and osteoporosis is a kn... more Background: Prednisone is a common treatment for myasthenia gravis (MG), and osteoporosis is a known potential risk of chronic prednisone therapy. Objective: Our aim was to evaluate the risk of serious fractures in a population-based cohort of MG patients. Methods: An inception cohort of patients with MG was identified from administrative health data in Ontario, Canada between April 1, 2002 and December 31, 2015. For each MG patient, we matched 4 general population comparators based on age, sex, and region of residence. Fractures were identified through emergency department and hospitalization data. Crude overall rates and sex-specific rates of fractures were calculated for the MG and comparator groups, as well as rates of specific fractures. Adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox regression. Results: Among 3,823 incident MG patients (followed for a mean of 5 years), 188 (4.9%) experienced a fracture compared with 741 (4.8%) fracture...

The Journal of Rheumatology, 2020

Objective.To compare differences in clinical activity and remuneration between male and female rh... more Objective.To compare differences in clinical activity and remuneration between male and female rheumatologists and to evaluate associations between physician gender and practice sizes and patient volume, accounting for rheumatologists’ age, and calendar year effects.Methods.We conducted a population-based study in Ontario, Canada, between 2000 to 2015 identifying all rheumatologists practicing as full-time equivalents (FTEs) or above and assessed differences in practice sizes (number of unique patients), practice volumes (number of patient visits), and remuneration (total fee-for-service billings) between male and female rheumatologists. Multivariable linear regression was used to evaluate the effects of gender on practice size and volume separately, accounting for age and year.Results.The number of rheumatologists practicing at ≥ 1 FTE increased from 89 to 120 from 2000 to 2015, with the percentage of females increasing from 27.0% to 41.7%. Males had larger practice sizes and pract...

International Journal of Population Data Science, 2022

IntroductionHealth care systems have faced unprecedented challenges due to the COVID-19 pandemic.... more IntroductionHealth care systems have faced unprecedented challenges due to the COVID-19 pandemic. Access to timely population-based data has been vital to informing public health policy and practice. MethodsWe describe how ICES, an independent not-for-profit research and analytic institute in Ontario, Canada, pivoted existing research infrastructure and engaged health system stakeholders to provide near real-time population-based data and analytics to support Ontario's COVID-19 pandemic response. ResultsSince April 2020, ICES provided the Ontario COVID-19 Provincial Command Table and public health partners with regular and ad hoc reports on SARS-CoV-2 testing and COVID-19 vaccine coverage. These reports: 1) helped identify congregate care/shared living settings that needed testing and prevention efforts early in the pandemic; 2) provided early indications of inequities in testing and infection in marginalized neighbourhoods, including areas with higher proportions of immigrants ...

Open Medicine, 2012

Although administrative health care databases have long been used to evaluate adverse drug effect... more Although administrative health care databases have long been used to evaluate adverse drug effects, responses to drug safety signals have been slow and uncoordinated. We describe the establishment of the Canadian Network for Observational Drug Effect Studies (CNODES), a collaborating centre of the Drug Safety and Effectiveness Network (DSEN). CNODES is a distributed network of investigators and linked databases in British Columbia, Alberta, Saskatchewan, Manitoba, Ontario, Quebec and Nova Scotia. Principles of operation are as follows: (1) research questions are prioritized by the coordinating office of DSEN; (2) the linked data stay within the provinces; (3) for each question, a study team formulates a detailed protocol enabling consistent analyses in each province; (4) analyses are “blind” to results obtained elsewhere; (5) protocol deviations are permitted for technical reasons only; (6) analyses using multivariable methods are lodged centrally with a methods team, which is respo...

International Journal of Population Data Science, 2021

ICES upholds a strong reputation for generating high-quality evidence to inform policy and practi... more ICES upholds a strong reputation for generating high-quality evidence to inform policy and practice through its collaborations with a broad range of health system stakeholders including government policymakers and healthcare providers including clinicians. Supported by the Ontario Ministry of Health and Ministry of Long-Term Care, the ICES Applied Health Research Question (AHRQ) Program leverages the data holdings and, scientific and clinical expertise to generate evidence tailored to the information needs of requestors. This paper outlines the approach, process, strengths, challenges and the resulting influence and impact to the healthcare landscape in Ontario.

BMJ Surgery, Interventions, & Health Technologies, 2021

ObjectivesThis study aimed to identify a threshold in annual surgeon volume associated with incre... more ObjectivesThis study aimed to identify a threshold in annual surgeon volume associated with increased risk of revision (for any cause) and deep infection requiring surgery following primary elective total knee arthroplasty (TKA).DesignA propensity score matched cohort study.SettingOntario, Canada.Participants169 713 persons who received a primary TKA between 2002 and 2016, with 3-year postoperative follow-up.Main outcome measuresRevision arthroplasty (for any cause), and the occurrence of deep surgical infection requiring surgery.ResultsBased on restricted cubic spline analysis, the threshold for increased probability of revision and deep infection requiring surgery was <70 cases/year. After matching of 51 658 TKA recipients from surgeons performing <70 cases/year to TKA recipients from surgeons with greater than 70 cases/year, patients in the former group had a higher rate of revision (for any cause, 2.23% (95% Confidence Interval (CI) 1.39 to 3.07) vs 1.70% (95% CI 0.85 to 2...

Annals of Internal Medicine, 2020

BACKGROUND Mortality after bariatric surgery has been previously studied, but cohort selection bi... more BACKGROUND Mortality after bariatric surgery has been previously studied, but cohort selection bias, completeness of follow-up, and collection of confounders have limited the inference of results. OBJECTIVE To determine the association between bariatric surgery and all-cause mortality. DESIGN Population-based matched cohort study. SETTING Ontario, Canada. PARTICIPANTS 13 679 patients who underwent bariatric surgery from January 2010 to December 2016 and 13 679 matched nonsurgical patients. INTERVENTION Bariatric surgery. MEASUREMENTS The primary outcome was all-cause mortality, with cause-specific mortality as the secondary outcome. Patients were matched according to age, sex, body mass index, and diabetes duration. RESULTS 13 679 patients who underwent bariatric surgery were matched to 13 679 nonsurgical patients. After a median follow-up of 4.9 years, the overall mortality rate was 1.4% (n = 197) in the surgery group and 2.5% (n = 340) in the nonsurgery group, with a lower adjusted hazard ratio (HR) of overall all-cause mortality (HR, 0.68 [95% CI, 0.57 to 0.81]). Patients aged 55 years or older had an absolute risk reduction of 3.3% (CI, 2.3% to 4.3%), with a lower HR of mortality in the surgery group (HR, 0.53 [CI, 0.41 to 0.69]). Observed relative effects were similar across sex; however, the observed association in absolute terms was greater in men. Surgery also was associated with lower cardiovascular mortality (HR, 0.53 [CI, 0.34 to 0.84]) and lower cancer mortality (HR, 0.54 [CI, 0.36 to 0.80]). LIMITATION The observational design limits causal inference. CONCLUSION Bariatric surgery was associated with substantially lower all-cause, cardiovascular, and cancer mortality. The lowered observed mortality of surgery was significant across most subgroups. The largest absolute effects were for men and patients aged 55 years or older. PRIMARY FUNDING SOURCE Ontario Bariatric Network.

Canadian Journal of Public Health, 2003

BackgroundRecent data suggest that although smoking during pregnancy has declined in North Americ... more BackgroundRecent data suggest that although smoking during pregnancy has declined in North America, this has more to do with falling rates of smoking initiation among women of childbearing age than with increased rates of pregnancy-related smoking cessation. One possible explanation is poor exposure to effective stop-smoking strategies. Better information about women who smoke during pregnancy may help target these interventions more effectively.MethodsThe study was a cross-sectional, self-administered survey of a consecutive sample of 916 (40.4% of eligible) women who delivered healthy babies in 1997–98 at a tertiary teaching hospital in Hamilton, Ontario. Our main focus was on health behaviours (smoking, drinking, eating, and exercise habits) before and during pregnancy; but we also included questions about the presence of (other) children and (other) smokers in the household, perceived health status, the subject’s age and level of education, and whether or not the present pregnancy was planned. Factors associated with pregnancy-related smoking cessation were identified using multiple logistic regression.ResultsRespondents were better educated and healthier, but smoked at rates similar to women of childbearing age in Hamilton at the time of the survey. Two thirds of prior smokers or 20% of respondents overall continued to smoke during pregnancy. After adjustment for other factors, three factors were associated with ongoing smoking during pregnancy: having other smokers in the household; having other children in the household; and not having post-secondary education.ConclusionsMany pregnant smokers are not being reached by current stop-smoking strategies. New ways to help these women and their partners are needed.RésuméContexteSelon des données récentes, si le tabagisme durant la grossesse est en baisse en Amérique du Nord, c’est plutôt parce que moins de femmes en âge de procréer se mettent à fumer qu’en raison d’une augmentation des taux de renoncement au tabac durant la grossesse. Une explication possible serait la piètre exposition à des stratégies antitabac efficaces. Une meilleure information sur les femmes qui fument durant la grossesse pourrait contribuer à mieux cibler de telles mesures.MéthodeDans cette étude transversale, un échantillon consécutif de 916 femmes (40,4 % de la population admissible) ayant donné naissance à des bébés en santé en 1997–1998 dans un hôpital d’enseignement de soins tertiaires à Hamilton (Ontario) a rempli un questionnaire d’auto-évaluation portant principalement sur les comportements liés à la santé (tabagisme, consommation d’alcool, alimentation et exercice) avant et durant la grossesse, mais comportant aussi des questions sur la présence d’(autres) enfants et d’(autres) fumeurs dans le ménage, sur l’état de santé subjectif, sur l’âge et le niveau d’instruction du sujet et sur le fait que la grossesse en cours ait été planifiée ou non. Les facteurs associés au renoncement au tabac durant la grossesse ont été cernés par régression logistique multiple.RésultatsLes répondantes étaient mieux instruites et en meilleure santé que l’ensemble des femmes en âge de procréer vivant à Hamilton au moment de l’enquête, mais leurs taux de tabagisme étaient semblables. Les deux tiers des anciennes fumeuses (20 % de l’ensemble des répondantes) ont continué à fumer durant leur grossesse. Après rajustement selon d’autres facteurs, nous avons relevé trois facteurs associés au maintien du tabagisme durant la grossesse: la présence d’autres fumeurs dans le ménage; la présence d’autres enfants dans le ménage; et l’arrêt des études après le secondaire.ConclusionDe nombreuses fumeuses enceintes ne sont pas touchées par les stratégies antitabac actuelles. Il faudrait trouver de nouvelles façons d’aider ces femmes et leurs partenaires.

Drug and alcohol dependence, Oct 1, 2018

The Canadian opioid crisis is a complex, multifaceted problem involving prescribed, diverted and ... more The Canadian opioid crisis is a complex, multifaceted problem involving prescribed, diverted and illicitly manufactured opioids. This study sought to characterize the contribution of prescribed opioids to opioid-related hospitalizations in Canada. We conducted a cross-sectional study of all individuals who were admitted to hospital for opioid toxicity in British Columbia (BC), Manitoba and Ontario between April 2015 and March 2016. We used prescription claims to ascertain active prescription opioid use at time of hospital admission. In secondary analyses, we defined recent opioid prescriptions as those that were dispensed in the 30 and 180 days up to and including admission, and the prevalence of active co-prescription of benzodiazepines with opioids at time of overdose. We identified 2599 instances of opioid toxicity over the study period. In BC, 34.1% of hospital visits for overdose occurred in people with an active opioid prescription, compared to 52.2% (47 of 90) in Manitoba and...

JAMA internal medicine, 2018

Overlapping surgery, also known as double-booking, refers to a controversial practice in which a ... more Overlapping surgery, also known as double-booking, refers to a controversial practice in which a single attending surgeon supervises 2 or more operations, in different operating rooms, at the same time. To determine if overlapping surgery is associated with greater risk for complications following surgical treatment for hip fracture and arthritis. This was a retrospective population-based cohort study in Ontario, Canada (population, 13.6 million), for the years 2009 to 2014. There was 1 year of follow-up. This study encompassed 2 large cohorts. The "hip fracture" cohort captured all persons older than 60 years who underwent surgery for a hip fracture during the study period. The "total hip arthroplasty" (THA) cohort captured all primary elective THA recipients for arthritis during the study period. We matched overlapping and nonoverlapping hip fractures by patient age, patient sex, surgical procedure (for the hip fracture cohort), primary surgeon, and hospital. P...

CMAJ open, Jan 22, 2017

In February 2012, a reformulated tamper-deterrent form of long-acting oxycodone, OxyNeo, was intr... more In February 2012, a reformulated tamper-deterrent form of long-acting oxycodone, OxyNeo, was introduced in Canada. We investigated the impact of the introduction of OxyNeo on patterns of opioid prescribing. We conducted population-based, cross-sectional analyses of opioid dispensing in Canada between 2008 and 2016. We estimated monthly community pharmacy dispensing of oral formulations of codeine, morphine, hydromorphone and oxycodone, and a transdermal formulation of fentanyl, and converted quantities to milligrams of morphine equivalents (MMEs) per 1000 population. We used time series analysis to evaluate the effect of the introduction of OxyNeo on these trends. National dispensing of long-acting opioids fell by 14.9% between February 2012 and April 2016, from 36 098 MMEs to 30 716 MMEs per 1000 population (p < 0.01). This effect varied across Canada and was largest in Ontario (reduction of 22.8%) (p = 0.01) and British Columbia (reduction of 30.0%) (p = 0.01). The national rat...

BMJ (Clinical research ed.), Jan 17, 2017

Objective To determine the safety of direct oral anticoagulant (DOAC) use compared with warfarin ... more Objective To determine the safety of direct oral anticoagulant (DOAC) use compared with warfarin use for the treatment of venous thromboembolism.Design Retrospective matched cohort study conducted between 1 January 2009 and 31 March 2016.Setting Community based, using healthcare data from six jurisdictions in Canada and the United States.Participants 59 525 adults (12 489 DOAC users; 47 036 warfarin users) with a new diagnosis of venous thromboembolism and a prescription for a DOAC or warfarin within 30 days of diagnosis.Main outcome measures Outcomes included hospital admission or emergency department visit for major bleeding and all cause mortality within 90 days after starting treatment. Propensity score matching and shared frailty models were used to estimate adjusted hazard ratios of the outcomes comparing DOACs with warfarin. Analyses were conducted independently at each site, with meta-analytical methods used to estimate pooled hazard ratios across sites.Results Of the 59 525...

Circulation, Jan 13, 2016

The Journal of Urology, 2017

Randomized controlled trials suggest an increased risk of heart failure with dutasteride, which i... more Randomized controlled trials suggest an increased risk of heart failure with dutasteride, which inhibits both the type 1 and type 2 isoforms of 5-α reductase. In contrast, no such association has been suggested for finasteride, which selectively inhibits the type 2 isoform. We investigated the risk of cardiovascular events among patients receiving dutasteride relative to finasteride. Population-based cohort study of Ontario men aged 66 years or older who commenced treatment with dutasteride or finasteride between October 1, 2005 and March 31, 2015. For each individual treated with dutasteride, we identified one treated with finasteride, matching on a propensity score and calendar quarter of treatment initiation to account for temporal changes in prescribing. The primary outcome was hospitalization for heart failure; secondary analyses examined acute myocardial infarction and stroke. Cox proportional hazards regression was used to adjust for differences between groups. We studied 36,311 men who commenced dutasteride and 36,311 treated with finasteride. In the primary analysis, we found no difference in the risk of heart failure among patients receiving dutasteride relative to those receiving finasteride (adjusted hazard ratio 0.98, 95% confidence interval 0.88 to 1.08). Similarly, we found no difference in the risk of acute myocardial infarction (hazard ratio 0.94, 95% confidence interval 0.82 to 1.08) or stroke (hazard ratio 1.03, 95% confidence interval 0.88 to 1.20). In this population-based cohort study of more than 72,000 older men, dutasteride was not associated with an increased risk of cardiovascular events relative to finasteride.

Clinical journal of the American Society of Nephrology : CJASN, Jan 27, 2016

Assisted peritoneal dialysis is a treatment option for individuals with barriers to self-care who... more Assisted peritoneal dialysis is a treatment option for individuals with barriers to self-care who wish to receive home dialysis, but previous research suggests that this treatment modality is associated with a higher rate of hospitalization. The objective of our study was to determine whether assisted peritoneal dialysis has a different rate of hospital days compared to in-center hemodialysis. We conducted a multicenter, retrospective cohort study by linking a quality assurance dataset to administrative health data in Ontario, Canada. Subjects were accrued between January 1, 2004 and July 9, 2013. Individuals were grouped into assisted peritoneal dialysis (family or home care assisted) or in-center hemodialysis on the basis of their first outpatient dialysis modality. Inverse probability of treatment weighting using a propensity score was used to create a sample in which the baseline covariates were well balanced. The study included 872 patients in the in-center hemodialysis group a...

JAMA internal medicine, 2016

The association between incretin-based drugs, such as dipeptidyl peptidase 4 (DPP-4) inhibitors a... more The association between incretin-based drugs, such as dipeptidyl peptidase 4 (DPP-4) inhibitors and glucagon-like peptide 1 (GLP-1) agonists, and acute pancreatitis is controversial. To determine whether the use of incretin-based drugs, compared with the use of 2 or more other oral antidiabetic drugs, is associated with an increased risk of acute pancreatitis. A large, international, multicenter, population-based cohort study was conducted using combined health records from 7 participating sites in Canada, the United States, and the United Kingdom. An overall cohort of 1 532 513 patients with type 2 diabetes initiating the use of antidiabetic drugs between January 1, 2007, and June 30, 2013, was included, with follow-up until June 30, 2014. Current use of incretin-based drugs compared with current use of at least 2 oral antidiabetic drugs. Nested case-control analyses were conducted including hospitalized patients with acute pancreatitis matched with up to 20 controls on sex, age, c...

CMAJ open

Recently, several new atypical antipsychotic agents have been introduced in Ontario, and regulato... more Recently, several new atypical antipsychotic agents have been introduced in Ontario, and regulatory warnings have been issued regarding use of atypical antipsychotics in older adults. We sought to establish the impact of newer atypical antipsychotics on prescribing rates and costs. We performed a population-based cross-sectional study of Ontario adults aged 65 years or more using atypical antipsychotics from Jan. 1, 2007, to Mar. 31, 2013. These people have universal access to publicly funded drugs through the Ontario Health Insurance Plan and the Ontario Drug Benefit. We conducted time-series analysis to assess the impact of the introduction of new atypical antipsychotics on rates of use of atypical antipsychotics and associated expenditures. Rates of atypical antipsychotic use increased following the introduction of new agents in 2009, from 27.6 users per 1000 older adults in the third quarter of 2009 to 29.1 users per 1000 older adults at the end of the study period (p = 0.04). A...