{"id":{"repo_id":"toronto-retro","oai_identifier":"oai:utoronto.scholaris.ca:1807/69047"},"canonical_url":"https://search.dev.ndltd.org/etd/toronto-retro/oai:utoronto.scholaris.ca:1807/69047","repository":{"repo_id":"toronto-retro","name":"University of Toronto","base_url":"https://utoronto.scholaris.ca/server/oai/request"},"display":{"title":"A Risk Stratification Model for Adult Patients with Obstructive Sleep Apnea: Development and Evaluation","abstract":"Despite emerging evidence that obstructive sleep apnea (OSA) may cause cardio-metabolic disturbances independently of known risk factors, the strength and significance of this association remains unclear. This thesis is comprised of three studies assessing the long term-consequences of OSA, and specifically the prognostic value of OSA-related variables for cardiovascular (CV) events, all-cause mortality and incident diabetes. Methods: The first study is a systematic review of longitudinal studies, from 1999 to 2011. Quality was assessed using published guidelines. Studies two and three linked a clinical sleep database to Ontario health administrative databases for the period of 1991 to 2011 to examine the relationship between OSA variables and a composite CV outcome and incident diabetes. For the latter, we assembled a cohort free of diabetes at baseline, as defined by health administrative data. Cox regression models were used to investigate the association between of OSA-related predictors and outcomes of interest, controlling for potential confounders. Study one identified significant relationships between OSA and all-cause mortality and composite CV outcome in men; associations with other outcomes remain uncertain. Among OSA-related variables, only apnea-hypopnea index (AHI) was a consistent predictor. Limitations of the clinically-based studies were small numbers of events, weak definitions of outcomes, and inconsistency in polysomnographic scoring criteria over time. Study two found that 1,172 (11.5%) of 10,149 participants experienced our composite CV event over a median follow-up of 68 months. In a fully adjusted model, the following OSA-related variables were significant independent predictors: time spent with oxygen saturation (SaO2) < 90%, sleep time, awakenings, periodic leg movements, heart rate, and presence of daytime sleepiness. In study three, of 8,678 cohort participants without diabetes at baseline, 1,017 (11.7%) developed incident diabetes over a median follow-up of 67 months. In fully-adjusted models, patients with AHI > 30 had a 30% higher hazard of developing diabetes than those with AHI < 5. Among other OSA-related variables, REM-AHI, and SaO2<90%, heart rate and neck circumference were associated with incident diabetes. Conclusions: Based on these studies, we demonstrated that OSA-related predictors significantly and independently contribute to the risk for occurrence of composite CV outcome and incidence diabetes.","abstract_html":"Despite emerging evidence that obstructive sleep apnea (OSA) may cause cardio-metabolic disturbances independently of known risk factors, the strength and significance of this association remains unclear. This thesis is comprised of three studies assessing the long term-consequences of OSA, and specifically the prognostic value of OSA-related variables for cardiovascular (CV) events, all-cause mortality and incident diabetes. Methods: The first study is a systematic review of longitudinal studies, from 1999 to 2011. Quality was assessed using published guidelines. Studies two and three linked a clinical sleep database to Ontario health administrative databases for the period of 1991 to 2011 to examine the relationship between OSA variables and a composite CV outcome and incident diabetes. For the latter, we assembled a cohort free of diabetes at baseline, as defined by health administrative data. Cox regression models were used to investigate the association between of OSA-related predictors and outcomes of interest, controlling for potential confounders. Study one identified significant relationships between OSA and all-cause mortality and composite CV outcome in men; associations with other outcomes remain uncertain. Among OSA-related variables, only apnea-hypopnea index (AHI) was a consistent predictor. Limitations of the clinically-based studies were small numbers of events, weak definitions of outcomes, and inconsistency in polysomnographic scoring criteria over time. Study two found that 1,172 (11.5%) of 10,149 participants experienced our composite CV event over a median follow-up of 68 months. In a fully adjusted model, the following OSA-related variables were significant independent predictors: time spent with oxygen saturation (SaO2) &lt; 90%, sleep time, awakenings, periodic leg movements, heart rate, and presence of daytime sleepiness. In study three, of 8,678 cohort participants without diabetes at baseline, 1,017 (11.7%) developed incident diabetes over a median follow-up of 67 months. In fully-adjusted models, patients with AHI &gt; 30 had a 30% higher hazard of developing diabetes than those with AHI &lt; 5. Among other OSA-related variables, REM-AHI, and SaO2&lt;90%, heart rate and neck circumference were associated with incident diabetes. Conclusions: Based on these studies, we demonstrated that OSA-related predictors significantly and independently contribute to the risk for occurrence of composite CV outcome and incidence diabetes.","abstract_has_math":false,"creators":["Kendzerska, Tetyana"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":"Health Policy, Management and Evaluation","school":null,"contributors":[],"advisors":["Tomlinson, George"],"committee_chairs":[],"committee_members":[],"year":2014,"date_issued":"2014-06","date_published":"2014-06","updated_at":"2026-07-27T21:28:05Z","subjects":["clinical epidemiology","Sleep-Disordered Breathing","long-term adverse outcomes","predictive modelling"],"languages":["en_ca"],"rights":["Attribution-NonCommercial-ShareAlike 2.5 Canada"],"rights_urls":["http://creativecommons.org/licenses/by-nc-sa/2.5/ca/"],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/1807/69047","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Tomlinson, George"]},{"key":"dc:contributor.department","label":"Department","values":["Health Policy, Management and Evaluation"]},{"key":"dc:creator","label":"Author","values":["Kendzerska, Tetyana"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2014-06"]},{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2015-06-17T19:12:00Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["WITHHELD_ONE_YEAR","2015-06-17T19:12:00Z"]},{"key":"dc:date.issued","label":"Date","values":["2014-06"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["clinical epidemiology","Sleep-Disordered Breathing","long-term adverse outcomes","predictive modelling"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en_ca"]},{"key":"dc:rights","label":"Dc Rights","values":["Attribution-NonCommercial-ShareAlike 2.5 Canada"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://creativecommons.org/licenses/by-nc-sa/2.5/ca/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/1807/69047"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Despite emerging evidence that obstructive sleep apnea (OSA) may cause cardio-metabolic disturbances independently of known risk factors, the strength and significance of this association remains unclear. This thesis is comprised of three studies assessing the long term-consequences of OSA, and specifically the prognostic value of OSA-related variables for cardiovascular (CV) events, all-cause mortality and incident diabetes. Methods: The first study is a systematic review of longitudinal studies, from 1999 to 2011. Quality was assessed using published guidelines. Studies two and three linked a clinical sleep database to Ontario health administrative databases for the period of 1991 to 2011 to examine the relationship between OSA variables and a composite CV outcome and incident diabetes. For the latter, we assembled a cohort free of diabetes at baseline, as defined by health administrative data. Cox regression models were used to investigate the association between of OSA-related predictors and outcomes of interest, controlling for potential confounders. Study one identified significant relationships between OSA and all-cause mortality and composite CV outcome in men; associations with other outcomes remain uncertain. Among OSA-related variables, only apnea-hypopnea index (AHI) was a consistent predictor. Limitations of the clinically-based studies were small numbers of events, weak definitions of outcomes, and inconsistency in polysomnographic scoring criteria over time. Study two found that 1,172 (11.5%) of 10,149 participants experienced our composite CV event over a median follow-up of 68 months. In a fully adjusted model, the following OSA-related variables were significant independent predictors: time spent with oxygen saturation (SaO2) < 90%, sleep time, awakenings, periodic leg movements, heart rate, and presence of daytime sleepiness. In study three, of 8,678 cohort participants without diabetes at baseline, 1,017 (11.7%) developed incident diabetes over a median follow-up of 67 months. In fully-adjusted models, patients with AHI > 30 had a 30% higher hazard of developing diabetes than those with AHI < 5. Among other OSA-related variables, REM-AHI, and SaO2<90%, heart rate and neck circumference were associated with incident diabetes. Conclusions: Based on these studies, we demonstrated that OSA-related predictors significantly and independently contribute to the risk for occurrence of composite CV outcome and incidence diabetes."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["PhD"]},{"key":"dc:title","label":"Title","values":["A Risk Stratification Model for Adult Patients with Obstructive Sleep Apnea: Development and Evaluation"]}]}],"canonical_facts":{"dc:contributor.advisor":["Tomlinson, George"],"dc:contributor.department":["Health Policy, Management and Evaluation"],"dc:creator":["Kendzerska, Tetyana"],"dc:date":["2014-06"],"dc:date.accessioned":["2015-06-17T19:12:00Z"],"dc:date.available":["WITHHELD_ONE_YEAR","2015-06-17T19:12:00Z"],"dc:date.issued":["2014-06"],"dc:description.abstract":["Despite emerging evidence that obstructive sleep apnea (OSA) may cause cardio-metabolic disturbances independently of known risk factors, the strength and significance of this association remains unclear. This thesis is comprised of three studies assessing the long term-consequences of OSA, and specifically the prognostic value of OSA-related variables for cardiovascular (CV) events, all-cause mortality and incident diabetes. Methods: The first study is a systematic review of longitudinal studies, from 1999 to 2011. Quality was assessed using published guidelines. Studies two and three linked a clinical sleep database to Ontario health administrative databases for the period of 1991 to 2011 to examine the relationship between OSA variables and a composite CV outcome and incident diabetes. For the latter, we assembled a cohort free of diabetes at baseline, as defined by health administrative data. Cox regression models were used to investigate the association between of OSA-related predictors and outcomes of interest, controlling for potential confounders. Study one identified significant relationships between OSA and all-cause mortality and composite CV outcome in men; associations with other outcomes remain uncertain. Among OSA-related variables, only apnea-hypopnea index (AHI) was a consistent predictor. Limitations of the clinically-based studies were small numbers of events, weak definitions of outcomes, and inconsistency in polysomnographic scoring criteria over time. Study two found that 1,172 (11.5%) of 10,149 participants experienced our composite CV event over a median follow-up of 68 months. In a fully adjusted model, the following OSA-related variables were significant independent predictors: time spent with oxygen saturation (SaO2) < 90%, sleep time, awakenings, periodic leg movements, heart rate, and presence of daytime sleepiness. In study three, of 8,678 cohort participants without diabetes at baseline, 1,017 (11.7%) developed incident diabetes over a median follow-up of 67 months. In fully-adjusted models, patients with AHI > 30 had a 30% higher hazard of developing diabetes than those with AHI < 5. Among other OSA-related variables, REM-AHI, and SaO2<90%, heart rate and neck circumference were associated with incident diabetes. Conclusions: Based on these studies, we demonstrated that OSA-related predictors significantly and independently contribute to the risk for occurrence of composite CV outcome and incidence diabetes."],"dc:description.degree":["PhD"],"dc:identifier.uri":["http://hdl.handle.net/1807/69047"],"dc:language.iso":["en_ca"],"dc:rights":["Attribution-NonCommercial-ShareAlike 2.5 Canada"],"dc:rights.uri":["http://creativecommons.org/licenses/by-nc-sa/2.5/ca/"],"dc:subject":["clinical epidemiology","Sleep-Disordered Breathing","long-term adverse outcomes","predictive modelling"],"dc:title":["A Risk Stratification Model for Adult Patients with Obstructive Sleep Apnea: Development and Evaluation"],"dc:type":["Thesis"]},"updated_at":"2026-07-27T21:28:05Z"}