Stroke in the Long Term. Prognosis, comorbidity, disability, readmission, and the caregiver perspective

Sammanfattning: Background: Stroke is a major cause of mortality and disability. Prognosis is constantly evolving and is affected by multiple factors, many of which have not previously been thoroughly analyzed. This thesis aims to provide an updated and comprehensive description of long-term prognosis after stroke, specifically exploring key factors such as comorbidity (Study II), pre-stroke functional dependency (Study III), readmission patterns (Study IV), and strain and well-being in informal caregivers (Study V). Method: The thesis describes patients registered in the Swedish Stroke Register (Riksstroke) in 2011 and 2013. Beyond Riksstroke’s regular follow-up surveys at three and 12 months, additional long-term surveys were conducted at three years (2013 cohort) and at five years (2011 cohort), which also enquired about the situation of informal caregivers. Data on comorbidity were obtained from the Swedish National Patient Register and the Swedish Prescribed Drug Register. The Charlson Comorbidity Index was used to guide selection of which chronic conditions to include. The Swedish National Patient Register also provided data on hospital readmissions. The modified Drug Rankin Scale was used to classify dependency level, and dependency was defined as a score of >3. Bivariate, multivariable, and hierarchical cluster analyses were performed and multiple imputation was used to minimize bias from loss to follow-up. Results: The common thesis cohort comprised 22 905 patients, and different subgroups were included in the individual studies. Total loss to follow-up was 12.7% at three months, 21.2% at 12 months, 20.3% at three years, and 16.9% at five years. Study I included the whole common cohort and provides a prognostic overview of both ischemic stroke (IS) and intracerebral haemorrhage (ICH). At five years after stroke, over two out of three patients with IS, and over three out of four patients with ICH, were either deceased or functionally dependent. The less favourable prognosis for ICH was largely explained by a higher early mortality. Study II included 11 775 pre-stroke independent IS patients. Comorbidity was common and had strong implications for long-term survival and functional outcome in all age groups. The largest effects were found for dementia, kidney and heart failure. Study III showed great heterogeneity among 5899 pre-stroke dependent IS patients. In those of severe pre-stroke dependency, comorbidity burden was higher, drug prescription was lower, and prognosis less favourable. Study IV included 10 092 pre-stroke dependent and independent IS patients. Readmission was common, particularly in the early phase after stroke, and a small group of patients with high comorbidity burden accounted for the majority of readmissions. The dominating cause was circulatory conditions. Study V explored the situation of 5063 informal caregivers to stroke patients. Life impact, need of support, and poor psychological well-being increased with degree of dependency of the stroke survivor. In caregivers to completely dependent survivors, 51.4% reported poor psychological well-being. Conclusions: The thesis describes substantial heterogeneity among stroke patients which is reflected in great variations in long-term prognosis, readmission patterns, and caregiver strain. This warrants a stratified and comprehensive approach to long-term support, healthcare, and research, which should also include informal caregivers.