Sex Differences in 28-Day Mortality of Ischemic Stroke in Iran and Its Associated Factors: A Prospective Cohort Study

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Abstract

Introduction

The mortality and morbidity rates of stroke in men and women have been reported differently and its effective factors have been discussed. The purpose of this study was to investigate sex differences in 28-day mortality of ischemic stroke and its associated factors.

Materials and Methods

This is a prospective cohort study conducted from June 2018 to September 2019 in patients with ischemic stroke referred to Firoozgar, Shariati and Sina hospitals in Tehran. Demographic data, risk factors, disease history, drug use, severity of stroke, and patient functional status were recorded in the hospital. The patients' functional status and severity of stroke were measured using the Modified Ranking Scale (MRS) and the National Institutes of Health Stroke Scale (NIHSS). After 28 days, the patients' survival status was monitored. Logistic regression was used to analyze the data.

Results

In this study, 703 patients were enrolled; of them, 260 (37.00%) were female and 443 (63.00%) were male. After 28 days, 21 female cases (8.17%) and 26 male (6.08%) ones died (P = 0.299). Functional status (OR = 4.65; 95%CI: 2.09 to 10.38), diastolic blood pressure (OR = 0.91; 95%CI: 0.85 to 0.96), warfarin use (OR = 0.15; 95%CI: 0.04 to 0.55), and hemoglobin (OR = 1.17; 95%CI: 1.02 to 1.35) were associated with 28-day mortality. Poor functional status in men had a greater association with 28-day mortality than women (OR 4.65 vs. 1.64). High diastolic blood pressure had a negative association with the 28-day mortality of cases and this association is more in women than in men (OR 0.88 vs. 0.91). High hemoglobin is a risk factor in men and a protective factor in 28-day mortality in women (OR 1.73 vs. 0.73). Smoking also had a greater association with 28-day mortality in women than men (OR 2.67 vs. 1.2).

Discussion

Twenty eight-day mortality was more in women than in men, but this difference was not significant. Women were older, had more severe stroke and poorer functional status than men. Variables including functional status, diastolic blood pressure, hemoglobin level, and smoking had interaction with sex, and their association with 28-day mortality rate was different between men and women. Sex differences should be considered, so that we can better manage stroke patients.

Introduction

Stroke is the second leading cause of death and the third leading cause of burden of disease, worldwide.1 The incidence and prevalence of this disease in men and women are increasing.2 Based on a systematic review, the incidence and prevalence of stroke in men are higher than women around the world.3 However, the burden of stroke and its mortality rate are higher in women than men, and nearly 60% of stroke-related deaths is among women.4 The outcome of stroke in women is worse than men, and according to the National Institutes of Health Stroke Scale (NIHSS) index, women experience more severe disease.5 Post-stroke functional status is also poorer in women than men and women require more care.6,7

Studies showed that the mortality rate in women in the first year following the stroke is 35% higher than in men, which could be due to women's older age, more severe strokes, and poorer functional status prior to stroke.8 The length of hospital stay has been reported to be longer in women than men. Furthermore, there was difference in response to treatment between the two sexes; however, the reason for this difference remained unknown. There are also controversies about post-stroke outcomes in men and women and its differences.9,10 Although information about sex differences in outcome of stroke is available worldwide, there are limited epidemiological information on sex differences in the developing countries.2 Iran is one of the middle-income countries and the prevalence of stroke in Iran, especially among young people, is significantly higher than the Western countries, but there is limited information on stroke and its related sex differences in Iran.11, 12, 13

Gathering comprehensive information about burden of stroke disease among men and women is required for management and planning of the health care system's priorities and allocation of the resources to each sex group. Furthermore, determining the associated factors on the sex differences could lead to decrease in complications of stroke.14 The aim of this study was to assess the sex differences in 28-day mortality rate of patients with ischemic stroke and determine factors which are associated with survival of these patients among the two sex groups.

Section snippets

Patients and settings

This study is a prospective cohort study on patients with ischemic stroke who were admitted to Firoozgar, Shariati and Sina teaching hospitals of Tehran from June 2018 to September 2019. These hospitals have neurology ward and intensive care unit (ICU), and stroke patients are managed by neurologists. In this study, the inclusion criteria were occurrence of ischemic stroke for the first time or recurrent stroke. Patients with Transient Ischemic Attack (TIA), hemorrhagic stroke or patients who

Demographic and clinical information of patients stratified by sex

In the present study, 703 patients with ischemic stroke were enrolled; of them 260 (37.00%) were female and 443 (63.00%) were male. The mean age of the subjects was 65.47±14.53 years, which was 64.91±14.48 in males and 66.42±14.60 in females.

Demographic and clinical data of the participants at the beginning of the study by sex are reported in Table 1. According to the results, women were older and had more severe stroke and poorer functional status than men. Diabetes, hypertension, history of

Discussion

In the current study, the mean age for men and women was 64.91years and 66.42 years, respectively, similar to other studies in which women's mean age was higher than men's.6,9,13,17, 18, 19 However, in the present study, the mean age of those individuals with stroke, from both men and women, was lower than its peer in some other studies.9,14,17,20 Likewise, Azarpazhooh et al. reported that the mean age of stroke in their study from Iran was lower than in Western countries.12 Besides, there was

Conclusion

In this study, we assessed the differences in risk factors and mortality rate 28 days after stroke between men and women. The results showed that the risk factors and outcome were different between men and women. Women were more likely to suffer from hyperlipidemia, hypertension and diabetes than men, and women were older and had poorer functional status and more severe strokes. The 28-day mortality rate in women was higher than in men but this difference was not statistically significant in

Acknowledgement

The authors appreciate the neurosurgery staff at Shariati, Firoozgar and Sina hospitals for their cooperation.

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    • Grant support: Tehran University of Medical Sciences

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