Temporal changes in functional outcome and case-fatality after ischaemic stroke and intracerebral haemorrhage in Sweden 2010–2019: an observational study from the Swedish Stroke Register (Riksstroke)

Abstract Introduction There are few recent studies on trends over time in functional outcome and mortality after stroke, with results separately presented for ischaemic stroke (IS) or ICH. We aimed to determine temporal changes in functional outcome and case-fatality 90 days after IS and ICH in Sweden between 2010 and 2019. Patients and methods We included patients (≥18 years) with first-ever IS or ICH registered in the Swedish Stroke Register (Riksstroke) between 2010 and 2019. Functional outcome data were based on the Riksstroke 90-day follow-up surveys and reported as distribution on the mRS. Multiple imputation was used for missing functional status in the survey non-responders (15.2% of total cohort). Mortality data were obtained from the Swedish Cause of Death Register, and “all-cause” mortality within 90 days was used as the outcome. Logistic regression was applied to calculate odds ratios for good functional outcome (mRS 0–2), and Cox regression was used to estimate hazard ratios for death within 90 days, with 2010–2012 as the reference period. Analyses were stratified by age groups (18–64, 65–74, 75–84, ≥ 85 years) and by 3 time periods (2010–2012, 2013–2016, 2017–2019). Results Between 2010 and 2019, 153,865 (87.3%) cases of IS and 22,289 (12.7%) cases of ICH were registered in Riksstroke. Good functional outcome (mRS 0–2) after 90 days increased in patients with IS from 49.2% in 2010–2012 to 52.4% in 2017–2019 (adjusted odds ratio aOR 1.12; 95% CI, 1.09–1.16) but not in patients with ICH (from 34.2% to 34.3%, aOR 0.96; 95% CI, 0.88–1.06). A significant improvement in functional outcome after IS from 2010–2012 to 2017–2019 was only observed in patients over 75 years. Crude 90-day case-fatality decreased in both IS (from 13.8% to 12.4%) and ICH (from 31.0% to 30.4%) from 2010–2012 to 2017–2019. Adjusted hazard ratios for case-fatality showed no significant changes over time for IS (0.99; 95% CI, 0.95–1.02) or ICH (1.00; 95% CI, 0.94–1.06). Conclusion We observed improvements in functional outcome after IS but not after ICH in Sweden between 2010 and 2019. Changes over time in functional outcome were more favourable in patients older than 75 years in both IS and ICH. Case-fatality decreased in IS and ICH, but this reduction was not significant after adjustment for confounding.