Study design to determine the effects of widespread restrictions on hospital utilization to control an outbreak of SARS in Toronto, Canada.

Schull, Michael J; Stukel, Therese A; Vermeulen, Marian J; Alter, David

CONTEXT Efforts to control an outbreak of severe acute respiratory syndrome (SARS) in Toronto, Canada, led to the imposition of major restrictions on nonurgent use of hospital-based services. OBJECTIVE To describe a methodology to determine the impact of the restrictions on healthcare utilization. DESIGN, SETTING, POPULATION: Population-based study of the Greater Toronto area and unaffected comparator regions, before, during and after the SARS outbreak (April 2001 to March 2004). OUTCOME MEASURES Population-based rates of hospital admissions, emergency department and outpatient visits, inter-hospital transfers, diagnostic testing and essential drug prescribing, adjusted for age and sex. METHODS We will assess the temporal patterns of healthcare utilization rates before, during and after the SARS restrictions in different regions using administrative health databases and longitudinal data analysis methods (generalized estimating equations). We will also use longitudinal cohort models to assess the effects of the restrictions to outcomes in cohorts diagnosed with specific chronic diseases. CONCLUSION We will document the extent to which utilization of healthcare services decreased during the SARS epidemic and identify clinical problem areas where SARS-related restrictions had adverse consequences on health. This work will have planning implications for future outbreaks of SARS or other infectious diseases. Understanding how the outbreak control measures affected use of health services and ultimately the health of the population, is an important part of understanding the impact of SARS restrictions.