Application of geographically weighted regression for assessing spatial non-stationarity

Linear regression is a commonly used method of statistical analysis. However, it is not able to capture any spatial variations that may exist in the relationship between explanatory and response variables. We will study geographically weighted regression, which is a local regression method that can account for spatial non-stationarity that may exist. We will describe the model, estimation and hypothesis testing, both in theory and in simulation studies. We will also apply the method to analyze data collected on housing prices in the Boston metropolitan area

Serious adverse drug events in patients presenting to emergency departments and admitted to hospitals in Newfoundland and Labrador

The primary objective of this research was to examine the extent of adverse drug events (ADEs) in three age-related subgroups of patients (children aged ≤17 years, adults aged ≥18 years and elderly aged ≥65 years) either presenting to emergency departments (EDs) or admitted to hospitals in the Canadian province of Newfoundland and Labrador (NL). As secondary objectives, this research classified ADEs according to severity and preventability (wherever possible) and identified patients' demographic and clinical characteristics that can predict occurrence of ADEs. -- This dissertation research was comprised of three empirical studies, each of which led to a manuscript for publication. The first and second studies used retrospective reviews of patients' ED charts to determine prevalence, severity, and preventability of ADEs among children and adults presenting to EDs. The third study used a population-based retrospective cohort design over a 12-year period to detect adverse drug reactions (ADRs) using diagnosis codes in the hospital discharge abstract. The aim of this study was to determine the incidence of ADRs among elderly hospitalized patients and to assess patient-related risk of ADRs. -- We found that 2.1% (95% CI: 1.6-2.6) of pediatric ED visits and 2.4% (95% CI: 1.8-3.0) of adult ED visits were due to serious ADEs, of which 20% and 29%, respectively, were considered preventable. In the cohort of elderly hospitalized patients, the incidence of ADRs was 15.2 per 1,000 person-years (95% CI: 14.8-15.7). Children with and without ADE-related ED visits were similar with respect to mean age and mean number of medications, whereas adults with ADE-related ED visits were older, prescribed more medications and had a higher number of comorbidities compared to their non-ADE counterparts. In elderly hospitalized patients, comorbidity from chronic diseases and the severity of patient's underlying illness, rather than advancing age and sex, increased the likelihood of recurrent events. The drug classes associated with or implicated to ADEs were dissimilar among the three age-related subgroups of patients. -- By comprising the findings of the three studies together, we concluded that an ADE prevention strategy should be targeted at patient-specific physiologic and functional characteristics, and high-risk medications, as opposed to focusing individual's chronological age