Predictors of Intermediate-term Mortality of Stroke Patients in East Azerbaijan

Abstract

Introduction and background The current study aimed to consider the predictors of intermediate-term (six months) mortality in patients hospitalized for first ever stroke in East Azerbaijan. Methods: The present cohort study included all new cases of strokes hospitalized in Imam Reza and Razi hospitals of Tabriz from march 21st to November 21st in the year 2014. The severity of stroke was determined using National Institute of Health Stroke Scale (NIHSS). The questionnaire used in this study included demographic status and history of risk factors, diseases and medication history which was completed by patients or the persons accompanying them thorough face to face interviews. The patients were followed up for a period of six months. The predictors of six-month mortality were decided by Cox proportional Hazard model. P value less than 0.05 was considered as meaningful level. Data was analyzed using SPSS 21. Results: A total of 576 cases definitely diagnosed with strokes were included in this study.308 (53.5) cases were male and 268 (46.5 percent) were female. Their averaged age for males was 70.15 ±13.12. The mean age of dead patients in the six-month period was 73.54 (± 11.47) and for the survivors were 68/42 (± 28.13). There was a statistically significant difference between the mean age of the survivors and the dead patients after follow up (P <0.001). During the six-month follow up period, 135(23%) cases died. Six-month case-fatality rate was 10.8% in men and 12.7% in women and this difference was not found significant between male and female. (P = 0.05). Six months' case-fatality rate was 14.2% hemorrhagic and in ischemic type 2.9 percent. There was a significant difference between the stroke type and six months mortality mortality. Hemorrhagic stroke patients had a high case-fatality (P <0.001). According to the log rank test, there was a statistically significant difference in severity of stroke and typing stroke. According to model, after adjusting other variables, the type of hemorrhagic stroke with a hazard ratio (HR) of 2. 2 times compared to ischemic stroke (95 % CI 1.49-3.24), considering the category of ≤5 as our reference category of severity, the hazard ratio for the stroke severity in range 6-14, 4.22(95 % CI 2.36-7.56), and for severity ≥20 was 5.34 (95 % CI 2.81- 10.12). Increased age (over 65), equally, increased the risk of mortality. For example, in comparison with age group <65hazard ratio for ages of >65was 1.61(95 % CI 1.04– 2.51) were an independent risk factor for six months of stroke. Discussion and conclusion: The results of this study confirmed the effects of severity (NIHSS>15), increased age, hemorrhagic subtype on six-month mortality of stroke patients. It is recommended that in health care services special attention be given to these specific groups.