Exploration of the spatial patterns and determinants of asthma prevalence and health services use in Ontario using a Bayesian approach

The purpose of this study was to examine the spatial variability of asthma outcomes in Ontario, Canada and broad environmental factors that contribute to this variability. Age-/sex-standardized asthma prevalence and health services use rates (2003–2013) were obtained from a provincial cohort of asthma patients. Employing an ecological-level study design, descriptive and Bayesian spatial regression analyses were used to examine patterns of asthma outcomes and their relationship to physical environment, socioeconomic environment and healthcare factors. Significant spatial variation in asthma outcomes was found between southern urban/suburban areas and northern/rural areas. Rurality was found to have a substantial effect on all asthma outcomes, except hospitalizations. For example, the most rural areas were associated with lower asthma prevalence and physician visits [RR = 0.708, 95% credible interval (CI): 0.636–0.795 and RR = 0.630, 95% CI: 0.504–0.758, respectively], and with higher ED visits (RR = 1.818, 95% CI: 1.194–2.858), when compared to urban areas. Strong associations were also found between material deprivation and ED visits (RR = 1.559, 95% CI: 1.358–1.737) and hospitalizations (RR = 1.259, 95% CI: 1.143–1.374). Associations between asthma outcomes and environmental variables such as air pollution and temperature were also found. Findings can be expected to inform the development of improved public health strategies, which take into account local environmental, socioeconomic and healthcare characteristics.

本研究旨在探究加拿大安大略省哮喘结局的空间异质性，以及引发该异质性的各类环境影响因素。研究从省级哮喘患者队列中获取了2003-2013年经年龄与性别标准化后的哮喘患病率及卫生服务使用率数据。本研究采用生态学研究设计，通过描述性分析与贝叶斯空间回归分析（Bayesian spatial regression analysis），考察哮喘结局的分布模式及其与自然环境、社会经济环境及医疗保健相关因素的关联。研究发现，哮喘结局在南部城市/郊区与北部/农村地区间存在显著空间差异。除住院治疗结局外，农村属性对所有哮喘结局均存在显著影响。例如，相较于城市地区，农村程度最高的区域哮喘患病率更低（相对风险Relative Risk, RR=0.708，95%可信区间credible interval, CI：0.636–0.795）与医师就诊率更低（RR=0.630，95%CI：0.504–0.758），但急诊（Emergency Department, ED）就诊率更高（RR=1.818，95%CI：1.194–2.858）。此外，物质匮乏程度与急诊就诊（RR=1.559，95%CI：1.358–1.737）及住院治疗（RR=1.259，95%CI：1.143–1.374）存在强关联。本研究同时发现哮喘结局与空气污染、气温等环境变量间存在显著关联。本研究结果可为制定更完善的公共卫生策略提供参考依据，此类策略需充分结合当地环境、社会经济与医疗保健特征。