Browsing by Author "Heitman, Steven James"

Now showing 1 - 3 of 3
  • Thumbnail Image
    ItemOpen Access
    Cost-effectiveness of screening and treatment for schistosomiasis among refugees coming to Canada
    (2019-01-14) Webb, John Angus; McBrien, Kerry Alison; Spackman, David Eldon; Vaughan, Stephen; Heitman, Steven James; Fabreau, Gabriel E.
    Background: Depending on their countries of origin, between 12% and 73% of resettled refugees and asylum seekers from endemic countries are infected with schistosomiasis when they arrive in Canada. Many are asymptomatic, but they are at risk for complications that may develop decades later. In Canada, clinicians previously practiced watchful waiting, treating patients if they developed symptoms; but in 2011 new guidelines recommended screening and treatment instead. In the United States, refugees from Africa are presumptively treated for schistosomiasis before they leave their country of origin. The cost-effectiveness of screening or presumptive treatment for schistosomiasis has never been studied. Methods: We constructed a decision-tree model to examine the cost-effectiveness of three management strategies: watchful waiting; screening and treatment; and presumptive treatment. We obtained model data from the literature and other sources, predicting deaths and chronic complications caused by schistosomiasis; as well as costs, and net monetary benefit. Results: Presumptive treatment was cost-saving if the prevalence of schistosomiasis in the target population was greater than 2.4%. In our base case analysis, presumptive treatment was associated with an increase of 0.15 quality-adjusted life years and a cost savings of $383 per person, compared to watchful waiting. It was also more effective and less costly than screening and treatment. Interpretation: Presumptive treatment for schistosomiasis among recently resettled refugees and asylum claimants to Canada is less costly and more effective than watchful waiting or screening and treatment, in groups with prevalence greater than 2.4%. Our results support a revision of the current Canadian guidelines.
  • Thumbnail Image
    ItemOpen Access
    Economic evaluation of colerectal cancer screening for average risk individuals
    (2012) Heitman, Steven James; Manns, Braden; Hilsden, Robert
    Background: Colorectal cancer (CRC) is a common deadly cancer. Screening for CRC saves lives and is cost-effective, but it is unclear if one or more of the screening options are preferred. Methods: A Markov model was developed and validated and then used to conduct an economic evaluation of CRC screening for average risk individuals. All current CRC screening modalities and up to date CRC treatment costs were considered. A systematic review and meta-analysis of CRC and adenomatous polyp prevalence was also performed to inform the model. Results: The prevalence of non-advanced adenomas, advanced adenomas and CRC in 50-64 and 65-75 year olds was 17.1%, 3.8% and 0.1% and 17.3%, 8.2% and 0.7%, respectively. In the base case analysis CRC screening with annual FIT reduced the risk of CRC and CRC-related deaths and was associated with lower health care costs compared to no screening and the other screening options. Conclusion: Health policy decision makers should prioritize funding for CRC screening using FIT.
  • Thumbnail Image
    ItemOpen Access
    Sessile serrated lesions in focus: Examining temporal trends, patient risk factors, and the role of the endoscopist in lesion detection
    (2023-09-22) Mazurek, Matthew; Brenner, Darren Michael RIehl; Heitman, Steven James; Hilsden, Robert Jay; Lee, Joon; Ferraz, Jose Geraldo P
    Serrated polyps of the colorectum have become increasingly recognized as an important clinical entity, as these precursor lesions are hypothesized to be responsible for up to 25% of sporadic cases of colorectal cancer. Much confusion exists regarding these polyps; particularly, their classification and associated malignant risk due to varied nomenclature, evolving pathological criteria, and ongoing research in prognostication. A specific subtype, sessile serrated lesions (SSLs), are of particular interest, as they are the most prevalent premalignant subtype and are over-represented in cases of interval cancers. Accurate identification and risk assessment remains a challenge owing to variable detection of clinically relevant serrated lesions by endoscopists, high inter-observer variability in diagnosis by pathologists, and an incomplete understanding of risk of future neoplasia. In this thesis, we analyze over 75,000 screening colonoscopies performed over a five-year period at a dedicated, large volume, high-efficiency screening centre to identify trends in the endoscopic detection of SSLs. The intent of this work is to better understand the temporal factors influencing SSL detection prevalence, the patient risk factors that are associated with these lesions, and how detection is related to procedural and endoscopist factors. The analysis includes consideration of traditional statistical methods as well as novel machine learning algorithms. We demonstrated a positive temporal trend in SSL detection over study period and identified several patient, procedural, and endoscopist factors associated with SSL detection. Machine learning models improved upon the predictive capabilities of traditional statistical models, yet a significant proportion of variability in risk remained unexplained, underscoring the complexity of accurately predicting SSLs. Endoscopic detection of SSLs demonstrates strong correlation with other detection metrics, notably adenoma detection rate, implying a shared underlying skillset requisite for the identification of these distinct polyp types. This connection highlights opportunities for enhancing detection through benchmarking and established quality improvement strategies.