RESUMO
AIMS: Ambient air temperature may exacerbate the burden of chronic diseases on Ontario's healthcare system during mass gathering events. This study aimed to estimate the impact of increasing temperature in July and August on health services use for chronic conditions in Ontario's Golden Horseshoe region during the 2015 Pan American and Parapan American Games, using environmental and health administrative data from previous years. METHOD: Negative binomial regression was used to calculate incidence risk ratios for same-day health services use (hospitalisations, emergency department visits, physician office visits) for all causes, asthma, asthma-related conditions, diabetes and hypertension associated with unit increases in daily maximum temperature from 1 May to 31 August in 2008-2010. Sensitivity analysis was performed to estimate the added burden of an increased population size, in order to model an influx of visitors during the Games. RESULTS: In July and August, on days with daily maximum temperatures of 35 °C compared to 25 °C, we estimated seeing 7,827 more physician office visits for all causes in Ontario's Golden Horseshoe region. The estimated relative increase in physician office visits for diabetes due to temperature alone was 8.4%. With an estimated 10% increase in population, the increase in physician office visits for all causes tripled to an estimated 23,590. CONCLUSION: Temperature was identified as a potential contributor to greater health services use during the Games, particularly for those living with diabetes. These results highlight the importance of strategic delivery of health services during mass gathering events, and suggest a role for educating at-risk individuals on prevention behaviours, particularly on very hot days.