2. Centre
Cérébrovasculaire
COMORBIDITY ANALYSIS AND 3 MONTHS FUNCTIONAL OUTCOME IN ACUTE ISCHEMIC STROKE: DATA FROM ACUTE STROKE REGISTRY AND ANALYSIS OF LAUSANNE (ASTRAL)
Kakaletsis Nikolaos 1, Papavasileiou Vasileios 1, Lambrou Dimitrios 2, Eskandari Ashraf 2,Ntaios George 2, Michel Patrik 2
Department of Clinical Neurosciences and Preventive Medicine, Danube University in Krems, Austria
2. Stroke Center, Neurology Service, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland.
LARISSA 
21 March 2015

3. Introduction
Comorbidity has been shown to be highly prevalent in stroke patients, especially in the older population.
The phenomenon of comorbidity is relevant because it often has a negative impact on health outcomes, quality of life, and health care use.
There is limited information on the prevalence and impact of comorbidities in stroke patients.
Clinical prognostic models in acute stroke would be helpful in predicting outcome in future patients (informing them and their relatives of reasons for treatment and clinical decisions, creating clinical risk groups and stratifying patients by disease severity in clinical trials).
Definitions: Comorbidity The medical conditions that exist at the time of diagnosis of the index disease or later, but that are not a consequence of the index disease and it is likely to be a significant factor influencing mortality and resource use in the hospital
Guralnik JM. Assessing the impact of comorbidity in the older population. Ann Epidemiol. 1996;6(5): van den Akker et al. Multimorbidity in general practice: prevalence, incidence, and determinants of co-occurring chronic and recurrent diseases. J Clin Epidemiol. 1998;51(5): Gijsen R, eta al. Causes and consequences of comorbidity: a review. J Clin Epidemiol. 2001;54(7): Ording AG, et al. Concepts of comorbidities, multiple morbidities, complications, and their clinical epidemiologic analogs. Clin Epidemiol. 2013;5: Feinstein AR. The pre-therapeutic classification of co-morbidity in chronic disease. Journal of Chronic Diseases. 1970;23(7):

4. Aim - Methods
We assessed 2,590 consecutive AIS patients from the ASTRAL-registry regarding 3 months unfavorable outcome, defined as a modified Rankin score of >2.
We constructed multivariable logistic regression models by including 45 comorbidities plus age or NIHSS or age & NIHSS or the ASTRAL-score as independent variables.
The β-coefficient of each covariate was used to generate an integer-based point scoring system.
We assessed the discriminatory power of the indexes and compared them by calculating the area-under-the-curve (AUC).
The aim was to evaluate the prevalence of comorbid diseases and their impact on handicap prediction in patients with acute ischemic stroke (AIS) in medium-term and to test whether they can add further predictive value in addition to already existing clinical predictive models (ASTRAL-score).
ASTRAL is the prospective registry of all consecutive patients admitted to the stroke unit or intensive care unit of the Central University Hospital of Vaud (CHUV) with acute ischemic stroke within 24 hours after last proof of well-being.

5. ASTRAL-score:
Was introduced recently for the prognosis of functional outcome in patients with AIS
It has been externally validated in three independent and ethnically diverse cohorts, showing remarkable consistency on predicting three-month functional outcome
Recently, it was validated externally for the prognosis of five-year dependence and mortality
Integer-based prognostic ASTRAL-score for the calculation of probability of unfavorable outcome in patients with acute ischemic stroke
Covariates
Score points
Age: for every 5 y a 1
Severity: for every NIHSS point a
Time delay from onset to admission>3hb 2
Range of visual field defect c
Acute glucose>7.3 or<3.7 mmol/L d
Level of consciousness decreased e 3
ASTRAL score Age, Severity, Time delay between stroke onset (or last proof of good health) and admission; R Range of visual field defect; A Acute glucose; and L Level of consciousness; NIHSS NIH Stroke Scale.
a. Counted from 0, b. 0 points when onset-to-admission time was 3 hours, c. 2 points for any stroke-related visual field defect; 0 points in the absence of visual field defect, d. 0 points for glucose 3.7 and 7.3 mmol/L, e. 0 points for normal level of consciousness.

6. Comorbidity Index for Handicap at 3 months
RESULTS
6 variables were positively and 2 negatively associated with 3 months handicap. The AUC of the derived comorbidity index differed slightly but statistically significantly from the pure ASTRAL-score’s AUC (0.857vs.0.846, p<0.001).
Comorbidity Index for Handicap at 3 months
points
ASTRAL-score 2
Renal Failure 3
Chronic Pulmonary Disease
Depression 4
Dementia
Coagulopathy
Metastatic Cancer -2
Hyperlipidemia -3
Patent foramen ovale
Conclusions
Adding an ASTRAL-derived comorbidities index to the existing ASTRAL-score slightly improves prediction of 3 months handicap.
This improvement is of limited clinical use because it more than doubles the number of variables needed for its calculation.