Objective: The aim of the present study was to investigate changes in stroke survival among Indigenous and non-Indigenous patients in the Northern Territory (NT).
Methods: A longitudinal study was undertaken of stroke patients admitted to NT public hospitals between 1992 and 2013. The Kaplan-Meier method and proportional hazards regression were used for survival analysis. A marginal structural model was applied to adjust for time-dependent confounders and informative censoring. RESULTS; There were 4754 stroke in-patients over the period, with 3540 new cases and 837 stroke deaths. Mean age of onset for Indigenous patients (51.7 years) was 12.3 years younger than that for non-Indigenous patients. After adjustments for confounders and loss to follow-up, in-hospital deaths were more likely among Indigenous patients (hazard ratio (HR) = 1.56; P < 0.01) and less likely among males (HR = 0.86; P < 0.05) and patients from remote areas (HR = 0.72; P < 0.01). There was a 3% decrease annually in mortality hazard from 1992 to 2013. Renal disease, cancer and chronic obstructive pulmonary disease had deleterious effects on stroke survival.
Conclusions: Stroke survival has improved in the NT over the past two decades. The marginal structural models provide a powerful methodological tool that can be applied to hospital administrative data to assess changes in quality of care and the impact of interventions.