Browsing by Author "Patel, Alka B."

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    Drip and Ship versus Mothership: Transportation and Treatment Strategies for Acute Ischemic Stroke Patients
    (2019-07-22) Holodinsky, Jessalyn Kathryn; Hill, Michael D.; Williamson, Tyler S.; Demchuk, Andrew M.; Patel, Alka B.
    Ischemic stroke with large vessel occlusion can be treated with alteplase and/or endovascular therapy. While endovascular therapy has been proven more effective than alteplase the administration of both treatments is highly time sensitive. There are geographic disparities in access to endovascular therapy. For patients outside the immediate vicinity of a hospital equipped to perform endovascular therapy it is unknown whether transport directly to an endovascular center for alteplase and endovascular therapy (mothership) or transport to the closest centre for immediate alteplase treatment followed by transfer to the endovascular center (drip-and-ship) will result in best patient outcomes. In this thesis, this is explored using theoretical conditional probability. Models were generated using existing data from clinical trials of stroke treatment, the accuracy of prehospital large vessel occlusion screening tools, and time from onset to stroke treatment (a function of both geography and hospital efficiency). The models were used to determine which strategy predicts the greatest probability of excellent outcome for stroke patients in several different scenarios. The optimal transport strategy is influenced by three different factors, the impact of which is summarized as follows from the perspective of the drip and ship approach. First, the most probable diagnosis of the patient. As the positive predictive value of the large vessel occlusion screening tool decreases the importance of the drip and ship model is appreciated. Second, the speed of treatment at the receiving hospitals. Fast treatment at thrombolysis centres is key for the drip and ship model to remain viable. Finally, the patient’s travel time to and between the different hospitals. As the distance between the thrombolysis and endovascular centre increases again the importance of the drip and ship model is realized. This thesis presents a novel way of conceptualizing the pre-hospital transport of suspected stroke patients. Decision-making for pre-hospital transport can be modelled using existing clinical trial data; these models can be dynamically adapted to changing realities. As the radius of superiority of the different transport strategy is context specific regional customization transport protocols for stroke patients is essential.
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    Examining Neighbourhood Socioeconomic Status, Anxiety and Depression during Pregnancy, and Preterm Birth
    (2019-07-10) Adhikari Dahal, Kamala; Metcalfe, Amy; Patten, Scott B.; Williamson, Tyler S.; Patel, Alka B.
    Background: Understanding of influence of anxiety, depression, and neighbourhood socioeconomic status (SES) on the risk of preterm birth (PTB) is unclear. This doctoral research examined the ability of neighbourhood SES to predict the risk of PTB, the utility of existing anxiety scales in measuring anxiety in pregnancy, and whether neighbourhood SES modified the association between anxiety and depression during pregnancy and PTB. Methods: This study used data from two pregnancy cohort studies in Alberta, Canada (n=5,528). The data were linked to neighbourhood SES data, derived from the Canadian census. A multilevel logistic regression prediction model was developed to examine whether neighbourhood SES improves the prediction of PTB. Confirmatory factor analysis and Spearman correlation were used to examine the utility of anxiety scales in pregnancy. A multivariable logistic regression model was used to assess whether neighbourhood SES modifies the association between anxiety and/or depression and PTB. Results: Neighbourhood level variance explained PTB by 6%. Neighbourhood SES combined with maternal characteristics predicted PTB with an area under the receiver operating characteristic curve (AUC) of 0.75. Maternal characteristics alone had AUC of 0.60. The model fit of anxiety scales ranged from inadequate to adequate. The correlation between the scales was low to moderate. The presence of both anxiety and depression, but neither anxiety nor depression alone, was significantly associated with PTB (OR=1.57, 95% CI=1.07, 2.29) and had significant interaction with neighbourhood deprivation (p-value=0.014). Conclusions: This research may suggest that women’s neighbourhood SES improves overall prediction of PTB and that it modifies the effects of anxiety and depression on risk of PTB. It may also indicate that existing anxiety scales do not measure anxiety as a single dimension and they are incomparable. These findings may guide the identification of women at increased risk for PTB and future research in the field.
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    Is there an association between spatial access to parks/green space and childhood overweight/obesity in Calgary, Canada?
    (BioMed Central, 2009-11-20) Potestio, Melissa L.; Patel, Alka B.; Powell, Christopher D.; McNeil, Deborah A.; Jacobson, Dan; McLaren, Lindsay