Risk factors related to death in patients with ischemic stroke

Background

Ischemic stroke is a disease with high mortality and morbidity because of the limited advance in therapeutics and lack of adequate technology for its treatment in some hospitals. The objective of our study is to demonstrate which factors are related to higher mortality, so they can be taken into account in selecting high risk groups at the time of treatment.

Methods

A retrospective study was made in patients who were admitted with diagnosis of ischemic stroke at the Hospital Médico Quirurgico del ISSS in a period of 18 months, from July 2000 to December 2001. Twenty-eight variables were analyzed, including clinical criteria, laboratory and imagining. A total of 106 patients were studied, excluding 14 patients who did not fulfill inclusion criteria. The statistical analysis was realized by chi-square test and Student t test and we took P < 0.05 to consider a significant difference. The odds ratio (OR) was determined for each variable.

Results

Ninety-two patients were studied, of which 36 (39.1%) were female with average age of 71 years, and 56 (60.9%) were male with average age of 69 years. Twenty-four (26.1%) died and 68 (73.9%) were discharged. We found only 10 variables to be statistically significant: mean arterial pressure (MAP) at admittance, seizures, temperature > 37.5°C, hyperglycemia, sepsis, age, arrhythmia, cardiovascular complications, computerized tomography (CT) results at admittance, and leucocytosis (Table 1). The average MAP in deceased patients was 91 mmHg, and pressures below this value were related to death with an OR = 5.92 (range: 1.93–18.59) and P = 0.0003. Patients who were given hospital discharge had an average MAP of 107 mmHg, and pressures = 107 mmHg had an OR = 0.24 (range: 0.06–0.85) and P = 0.012, which shows it is beneficial to maintain a relatively high MAP to ensure adequate cerebral perfusion. Other significant variables related to death were: temperature > 37.5°C at admittance, with OR = 13, and P = 0.000038; seizures with OR = 17.63, and P = 0.011; hyperglycemia (> 200 mg/dl) with OR = 6.27, and P = 0.00031; leucocytosis (WBC > 12,000) with OR = 13.11, and P = 0.0000005. In patients with a negative CT at admittance, an OR = 0.04 was found, with P = 0.000076. All patients with ischemic stroke and sepsis died.

Table 1

Conclusions

There are risk factors closely related to mortality in patients with ischemic stroke, some of which may be modified at admittance, such as temperature > 37.5°C, MAP < 91 mmHg, and hyperglycemia. Some require early detection to avoid further complications, such as seizures, arrhythmias and leucocytosis. Certain factors are related to lower mortality rate: age ≤ 69 years, negative CT at admittance and MAP ≥ 107 mmHg.