In this study stroke accounted 16.5 % of total medical admissions and 23.6 % of the total medical cases of in hospital mortality. This admission rate was higher than findings from Gambia in which the stroke patients made up 5% [32] and in southwestern Nigeria made up of 4.5% medical admission[33]. But the finding was in agreement with previous study conducted by Deresse B and Shaweno D in Hawasa Ethiopia in which stroke accounted for 13.7% of all medical admissions [19]. The elevated number of stroke admission in Ethiopia may be due to lack of awareness, poor risk factor control and being hospital based study with referral bias.
A total of 91(78.4%) patients were discharged being alive from the hospital with in hospital stroke mortality rate of (21.6%). From those discharged being alive more than half (57.8%) were discharged with improvement which was lower as compared to study by Masood et al in Pakistan (91%) [34], Jowi et al in kenya (93.8%) [35] and Tirschwell etal in Vietnam (65.8%) [21], but higher than study done by Gebremariam etal in Ethiopia (47.9%) [36]. But our finding was comparable with study done in Ethiopia by Greffie etal in which 59.18% of the patients were discharged with improvement [10]. The outcome/vital status of the patients during discharge may vary with the severity of stroke, set up of the hospital, complications, co morbidities associated with the patients and experts available in caring of the patient.
The median length of hospital stay was 9.21days which was shorter than previous studies by Walker etal 19 days [32], Jowi et al 12.5 days [35], Greffie etal 13 days [10], Gebremariam etal 11 days [36] and De Carvalho etal 15.4 days [37]. For the shorter length of hospital stay in our set up, multiple reasons could be explained. Some patients were rapidly improved and discharged due to the stroke unit provides better quality of care during the early phase as compared to other wards in the hospital. Secondly some patients were died rapidly, some discharged LAMA and others discharged with medical advice without improvement due to small bed occupy of the stroke unit of the hospital. In this regard, if the patient stayed longer than other patients and any improvement was observed, the bed would be left for new stroke patients. Additionally, in few patient’s delays in complimentary evaluations was one of the most feasible explanations for the prolonged admission time. This delayed evaluation will not only significantly increases the costs for stroke care, but also increases the risks for infection, other complications, and recurrence in patients with suboptimal treatment and evaluation.
The in-hospital stroke mortality (21.6%) was comparable with the study done by De Carvalho et al in Brazil 20.9% [37] and Desalu et al in Nigeria 23.8% [33]. But this was higher as compared study done by Deresse et al in Ethiopia 14.7% [19], Tirschwell etal in Vietnam 6.5% [21], Masood etal in Pakistan 9 % [34], Gebremariam etal in Ethiopia 12.0 % [36], Greffie et al in Ethiopia 13.3% [10] and Jowi et al in kenya (5%) [35]. In addition, this in hospital mortality was lower as compared to study done by Damasceno et al in Mozambique which was 33.3% [38], Atadzhanov etal in Zambia 40 % [20] and Walker et al in Gambia 57% [32]. The difference in hospital mortality rate could be due to different ways of stroke diagnosis, types of stroke, treatment approaches, risk factors, co morbidities, complications and in hospital patient care.
The prominent immediate causes suspected and forwarded by clinicians was increased intracranial pressure and respiratory failure secondary aspiration pneumonia, which complies with other studies particularly conducted in Ethiopia [10, 19]. Additionally, study done in Arabian Gulf countries reported that both neurologic and systemic complications accounted 63% of in hospital mortality [39]. But it was unlike to study conducted by Walker etal in Gambia revealing the most immediate cause of death was the initial stroke itself in 61% of patients [32]. The difference could be due to difference in physician’s duty note and prediction based on co morbidities as well as complications that were developed in the patient at the end of patient’s life. Prevention, early identification and management of complications like increased intracranial pressure and aspiration pneumonia factors would at least have salvage life of the some patients.
In general, the in hospital case mortality rate of stroke in this study was higher than reports from western studies, but was quite similar to SSA studies. This difference could reflect the limited access to hospital care, limited staffing, shortage of facilities for diagnosis, lack of necessary therapy and insufficient number of hospital beds for longer period care in developing countries. In addition to this some caregivers/patients belief that patients should die at their home origin, where they spent most of their lives, with family members around and caring for them. Absence of treatment with thrombolytic, the low frequency of treatment with antiplatelets for patients with ischemic stroke and lack of evaluation with neuroimaging suggest that suboptimal care be the most likely explanation for increased mortality of stroke in LMICs. Targeted interventions that reduce and control risk factors like hypertension, diabetes, hyperlipidemia and smoking as well as promoting physical activity and a healthy diet, could substantially reduce the burden of stroke [17].
The in hospital median survival time for patients who died in hospital was 4.38 days which was earlier as compared to study by Walker etal 7.5 days [32], Greffie etal 6 days [10] and Damasceno et al 6 days [38]. However it was relatively comparable with the study done by Deresse et al Ethiopia reporting that median survival time of the patients was 4.5 days after admission [19]. It has been stated that the high mortality rate in this study during the first one-week (17.2%) might be due to acute complications developed among patients like raised intracranial pressure and aspiration pneumonia.
Brain edema, urine incontinence, NIHSS>13 during hospital arrival and diagnosis of stroke clinically alone were the independent predictors of time to in hospital mortality. Except stroke severity other factors were not reported on study conducted study by Atadzhanov et al in Zambia [20]. In this study increased NIHSS was associated with stroke severity constituting decreased level of consciousness. High NIHSS score as a predictor of mortality was consistent with previous study by Deresse et al in Ethiopia [19]. But according to study by Sweileh et al chronic kidney disease, number of post-stroke complications and stroke subtype were independent predictors of in-hospital mortality among stroke patients [40].
In our current study brain edema as complication was one predictor of in hospital mortality unlike study by Mamushet et al in Ethiopia in which mortality was not significantly associated with increased intracranial pressure [41]. We believe that the number of in hospital complications was a reflection of the severity of stroke attack and therefore an independent predictor of in-hospital mortality in stroke patients. The difference in predictors of in hospital mortality could be due to sample size, study design, significance value considered and eligibility criteria of the patient.
The in hospital mortality was higher for hemorrhagic stroke (more than triple) compared to ischemic stroke patients that complies with previous findings [19, 20, 24]. As study by Das et al early onset mortality is common in hemorrhagic stroke, where late mortality is prevalent amongst ischemic stroke [42]. In contrary to our finding, study by Mamushet etal in Ethiopia showed that mortality was significantly higher for ischemic stroke cases compared to hemorrhagic stroke (P=0.049) [41]. This contrary finding by Mamushet et al might be due to the study design, study population and co morbidity of the cases. Similar to our finding, study by Deresse etal showed that the rate of stroke mortality was not different by age and sex [19].
Strength and limitation of the study
Strength of the study
This study had its own strength and unique contributions. The major strengths of this study was its prospective study design and the enrollment of consecutive patients. This prospective cohort study allowed for collection of accurate data on time-varying prevalence of multiple variables. We have assessed every factor longitudinally with a continuous clinical follow-up as far as possible within our setup, then we come to the conclusion by a standard statistical method. We used core and supplementary ascertainment strategies, combined with an independent direct assessment, to achieve recommended gold-standard ascertainment methods. Inclusion of incident cases and all events (first-ever and recurrent) within the study period provided a more accurate reflection of the burden of stroke.
The study provides a preliminary database on mortality and functional outcome which can inform stroke management strategies. The degree of the neurologic deficit on discharge was evaluated based on functional status score, unlike in other areas practical reasons which was categorized into those with and those without neurologic deficit. We have performed a detailed assessment including a NIHSS stroke scale allowing us to evaluate for determinants of outcome in series of patients with stroke. In addition we have used survival analysis method with competing risk that allowed us to estimate the risks of stroke mortality.
Limitation of the study
The study was associated with some limitations and drawbacks. First, this study was a hospital-based study rather than large community based study. Hospital based study may not reflect true picture of the stroke as extremely critical patients died before hospitalization and mild cases may have not reported to hospital. Additionally, hospital based study is subjected to referral bias, as most of the acute stroke patients’ visit our hospital only from the south western part of Ethiopia directly without any selection. These referral bias, single setup as well as convenience sampling approach used might not reflect the true burden and outcome of the stroke in our community. Hence extrapolations and generalization to the rest of the community should be done with caution. Even though the study was hospital based, having only one referral center might probably reflect the actual magnitude of stroke in the country. As well as, the mean age, the proportion of young adults, male predominance, incidence and mortality indices of our data were quite similar to other stroke epidemiological studies.
Secondly, etiologic investigation for stroke was infrequently performed by the lack of systematic cardiological examinations and brain imaging’s. Even about half the patients were diagnosed clinically alone to have stroke. Clinical way of diagnosis based on clinician judgment rather than biological may distort accuracy and reliability of the data. Diagnostic investigations were undertaken on the basis of the subject’s syndrome, rather than complete evaluation of the cases to rule out, as evidenced by the similar proportions of inadequate workup. Poor risk factor identification and diagnosis may underestimate or overestimates some factors. In many cases the investigators were not the primary treating physicians and it was difficult to validate some of the diagnosis made by other physicians. Finally, the sample size was small hampering the analysis of some prognostic indicators due to the short recruitment period. Indeed, a prospective community-based cohort design would require thousands of stroke-free subjects who would need to be followed up for several years to absolutely know the outcome of patient. In LMIC setting, resources are not available for this and results are urgently required to help implement the stroke intervention quadrangle.