Predictors of In-hospital Mortality of Acute Ischemic Stroke in Adult Population

INTRODUCTION

Stroke is the second most common cause of death and third leading cause of disability worldwide.[1] The in-hospital mortality rate of stroke of general ward group is 14.7% and 6.9% for stroke care unit group.[2] Advancing age, unconsciousness, severe stroke, large vessel stroke, atrial fibrillation, previous history of stroke, hyponatremia, high fasting blood sugar, and aspiration pneumonia were some of the predictors of mortality for a stroke.[3456] There is no consensus regarding the predictors of mortality in acute ischemic stroke among the researcher thus a definite scoring system for predicting the mortality of patient of acute ischemic stroke is still not practiced.

The management of acute stroke in low to middle-income countries is in snail's pace thus becoming a difficult task to handle the burden of acute stroke in health-care centers. Predicting the mortality of patient with stroke, identifying the high-risk patient and managing them with utmost care is still the unmet need of the country like Nepal. The data regarding the predictors of mortality from low to middle-income countries, where still the concept of stroke unit care is in infancy stage are limited.

This study is our endeavor to determine the predictor of the mortality of the patient of acute ischemic stroke in a tertiary care center in eastern Nepal by doing a retrospective analysis of patient of acute ischemic stroke admitted to the hospital.

MATERIALS AND METHODS

RESULTS

As shown in Table 1, we enrolled 257 patients with acute ischemic stroke in this study. The majority of the patient was male (58%). It occurred predominantly in the elderly population. Among the study population, 39.7% were a smoker and 41.2% had a history of alcohol intake. Most of the patient (57.6%) had a history of hypertension. Out of total participants, 53 patients (20.5%) patients died during hospital stay. The average length of hospital stay of admitted patients with acute ischemic stroke is 4 days.

Table 1 Baseline characteristics of study population

As shown in Table 2, patients with in-hospital mortality had significantly lower GCS score than those patients who survived (9 vs. 12, P < 0.001). There was no statistically significant difference in blood pressure in between survival and mortality group. Pulse rate (91 vs. 83, P = 0.009) and respiratory rate (24 vs. 21, P < 0.001) was significantly higher in mortality group than in survival group. Patients who died had a low saturation of oxygen than those who survived at baseline. There was no significant difference between the level of random blood sugar, haemoglobin, serum sodium in mortality and survival group.

Table 2 Clinical and laboratory parameters of study population who survived and had in-hospital mortality

DISCUSSION

In this 5-year retrospective analysis of acute ischemic stroke in a tertiary care center in eastern Nepal, The in-hospital mortality rate of acute ischemic stroke was 20.5%. This mortality rate is higher than reported by Dewan and Rana[7] from the tertiary care center in Central Nepal. This contrast in finding is due to the fact that the majority of patient recruited by them had the National Institutes of Health Stroke Scale (NIHSS) scale <15 which reflects a less severe form of stroke and may be due to the availability of specialized neurology care in their center. The in-hospital mortality rate of acute ischemic stroke was 4.5% in German stroke registry group as reported by Heuschmann et al.[8] This discrepancy in mortality rate from developed country reflects the urgent need of improvising the stroke care in middle- to low-income countries.

Modifiable risk factors such as hypertension, smoking, alcoholism, and diabetes mellitus were present in the majority of patient and similar findings were reported by studies in the other parts of Nepal.[910] These data coincide with the increasing prevalence rate of noncommunicable disease in the country[11] and raises the concern of stakeholder to focus on primary and secondary prevention of noncommunicable diseases.

In this study, the population who had in-hospital mortality had lower GCS score than those who survived (P < 0.001). GCS score is routinely practiced easy and noninvasive tool to prognosticate the traumatic brain injuries, stroke, and nontraumatic coma.[12] Mittal et al. reported GCS score of <8 as a predictor of the mortality,[13] which is similar to our finding.

The data showed that population who expired had a lower saturation of arterial oxygen than survival group (92% vs. 95%, P < 0.001). Hypoxia in acute ischemic stroke may be due to the aspiration pneumonia, brain stem stroke, heart failure, pulmonary embolism, and obstructive sleep apnea.[14] It increases the respiratory distress and may result in mortality of the patient. However, the data regarding the hypoxia and its impact on mortality of acute ischemic stroke are limited.

We found that higher respiratory rate as one of the predictors of the mortality of acute ischemic stroke (P < 0.001). Respiratory dysfunction in strokes such as Cheyne–Stokes breathing and tachypnea was associated with increased mortality of acute stroke.[15] Patient with tachypnea should be given utmost care and should evaluate them for the need of mechanical ventilation even at the emergency room.

Pulse rate was higher in mortality group than survival group. The causes of higher admission pulse rate are the large stroke, severe stroke (NIHSS >15), and atrial fibrillation.[16] The data from this study corroborate with Böhm et al. who reported in their study that faster admission heart rate predicts the mortality and poor functional outcome in a patient with acute ischemic stroke.[17] Admission pulse rate should be monitored carefully and those with higher pulse rate should be taken with utmost care.

CONCLUSION

In a patient with acute ischemic stroke, poor GCS, lower arterial oxygen saturation, tachypneic, and higher pulse rate predicts the in-hospital mortality.