This is an observational cohort study with a 5-year follow-up post-stroke. The STROBE-guidelines for observational studies were followed. Data was extracted from the extended Stroke Arm Longitudinal study at the University of Gothenburg (SALGOT-extended) (23–25). Participants resident in the Gothenburg urban area (within 35 km from the Sahlgrenska University Hospital), 18 years or older, admitted with a first time ischemic stroke (I63), intra cerebral haemorrhage (I61) or non-traumatic subarachnoid haemorrhage (I60) during 18 months in 2009–2010 at the neurosurgical clinic, stroke unit or the intensive care unit at the largest of the three hospitals creating Sahlgrenska University Hospital were eligible for inclusion in the present study. The Sahlgrenska University Hospital is the only centre in the area that provides interventions such as thrombectomy and thrombolysis.
Five years after stroke, the survivors received a questionnaire survey by mail. The survey included the Swedish version of the Stroke Impact Scale (SIS) 3.0 and the annual follow-up questionnaire from the Swedish Stroke Register. Only participants who replied to any of the SIS-questions were eligible for inclusion in the current study.
Baseline data from the acute phase were collected from medical charts. The National Institutes of Health Stroke Scale (NIHSS) (26) and the Hunt and Hess scale (H&H) (27) were assessed by medical doctor at hospital arrival. The NIHSS measures severity of neurological symptoms in ischemic stroke and intra cerebral haemorrhage and the scale range from 0–46, where a lower score is better. In the present study, a score of 0–2 was considered as very mild stroke, 3–4 as mild, 5–15 as moderate and > 16 as severe stroke. The H&H is used to assess severity of the subarachnoid haemorrhage. The H&H consists of five grades where a lower score suggests a less clinically severe presentation. The modified Rankin Scale (mRS) were assessed at discharge from hospital and was used to assess a person’s level of functional dependency. The mRS range from 0–5, and in the current study a dichotomisation of the mRS score was used where 0–2 represents functional independency and 3–5 functional dependency (28, 29). Cardiovascular disease (CVD) was considered as cardiac arrhythmias, coronary artery disease, heart failure, heart valve disease, or septal defects. Cardiovascular risk factor (CVR) was considered as CVD, diabetes, hypertension, or hyperlipidaemia.
The current study includes two questions from the annual Swedish Stroke Register questionnaire. Have you suffered a new stroke, with the answers yes or no. The second question, Do you feel depressed? has five possible answers which was dichotomised as followed: never/almost never/sometimes corresponding to not feeling depressed and often/all the time as feeling depressed (30).
The SIS questionnaire (31, 32) captures different aspects of stroke outcome and consists of 59 items in eight domains with questions rated in an ordinal scale 1–5 covering: strength, memory and thinking, mood and emotion control, communication and language, activities of daily living (ADL), mobility, hand function, and participation. Each domain score were then transformed using the following equation: domain score= (mean item score-1)/5 − 1 × 100, with each domain receiving a final total score out of 100 (31, 32). The composite physical domain (including strength, hand function, mobility and ADL) were used (31, 32). If a participant responded to less than 50% of the items in a domain, the results from the domain were excluded. The SIS-domain scores were dichotomised in the regression analysis, with scores ≥ 80 considered as full function (33). The SIS includes in addition a visual analogue scale (VAS) estimates the respondents self-perceived recovery from 1-100, a higher score is better.
All analyses were performed using IBM SPSS version 25.0. For analysing group differences, Mann–Whitney U test and Fischer’s exact test were used. Significance level was set to p < 0.05, two-tailed tests were used.
Based on the level of functional dependency (mRS), logistic regression analysis was used to; predict favourable outcome in each of the dichotomised SIS-domains: emotion, participation and composite physical. Potential predictor variables in each of the models were: recurrent stroke, feeling depressed, sex, age, stroke type, and CVR. Predictor variables were excluded prior to the multivariable analysis if: too few participants (< 5) in each subgroup, correlated rho > 0.7 or <-0.7 to other predictors, or if the contribution of the predictor variables were non-significant (p-value ≥ 0.25) in univariable regressions. Goodness of fit and accuracy of the multivariable regressions were tested using the Hosmer and Lemeshow test, the Nagelkerke R², and a Receiver Operating Characteristic (ROC)-curve. An area under the curve (AUC) of > 0.7 was considered acceptable accuracy, > 0.8 as excellent and > 0.9 as outstanding.