Browsing by Author "Lam, Stephen"
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Item Open Access Chronic obstructive pulmonary disease prevalence and prediction in a high-risk lung cancer screening population(2020-11-16) Goffin, John R; Pond, Gregory R; Puksa, Serge; Tremblay, Alain; Johnston, Michael; Goss, Glen; Nicholas, Garth; Martel, Simon; Bhatia, Rick; Liu, Geoffrey; Schmidt, Heidi; Atkar-Khattra, Sukhinder; McWilliams, Annette; Tsao, Ming-Sound; Tammemagi, Martin C; Lam, StephenAbstract Background Chronic obstructive pulmonary disease (COPD) is an underdiagnosed condition sharing risk factors with lung cancer. Lung cancer screening may provide an opportunity to improve COPD diagnosis. Using Pan-Canadian Early Detection of Lung Cancer (PanCan) study data, the present study sought to determine the following: 1) What is the prevalence of COPD in a lung cancer screening population? 2) Can a model based on clinical and screening low-dose CT scan data predict the likelihood of COPD? Methods The single arm PanCan study recruited current or former smokers age 50–75 who had a calculated risk of lung cancer of at least 2% over 6 years. A baseline health questionnaire, spirometry, and low-dose CT scan were performed. CT scans were assessed by a radiologist for extent and distribution of emphysema. With spirometry as the gold standard, logistic regression was used to assess factors associated with COPD. Results Among 2514 recruited subjects, 1136 (45.2%) met spirometry criteria for COPD, including 833 of 1987 (41.9%) of those with no prior diagnosis, 53.8% of whom had moderate or worse disease. In a multivariate model, age, current smoking status, number of pack-years, presence of dyspnea, wheeze, participation in a high-risk occupation, and emphysema extent on LDCT were all statistically associated with COPD, while the overall model had poor discrimination (c-statistic = 0.627 (95% CI of 0.607 to 0.650). The lowest and the highest risk decile in the model predicted COPD risk of 27.4 and 65.3%. Conclusions COPD had a high prevalence in a lung cancer screening population. While a risk model had poor discrimination, all deciles of risk had a high prevalence of COPD, and spirometry could be considered as an additional test in lung cancer screening programs. Trial registration (Clinical Trial Registration: ClinicalTrials.gov, number NCT00751660 , registered September 12, 2008)Item Open Access Methodology to minimize cost and time for new data warehouse implementations(2004) Lam, Stephen; Barker, Kenneth E.A data warehouse's many different components make setting one up a non-trivial and expensive task (R.K. 98). This thesis describes a new light-weight data warehouse implementation methodology that minimizes cost and production time while ensuring the core requirements of a typical data warehouse system are included. The methodology enables fast initial development with scalable architecture for future growth. From a maintenance perspective, the methodology minimizes the ongoing data refresh cost. This is important because data refresh cost is the major maintenance cost in a typical data warehouse system. The data quality is also improved by using the methodology. The above advantages are due to the small team structure, single database architecture, metadata approach, data modeling approach, Extract Transformation and Loading (ETL) approach, tools selection and web portal presented in the methodology.