Sex Differences in Case Fatality of Aneurysmal Subarachnoid Hemorrhage: A Systematic Review.

INTRODUCTION: Aneurysmal subarachnoid hemorrhage (SAH) is more common in women than in men, contrary to most cardiovascular diseases. However, it is unclear whether the case fatality rate (CFR) of SAH also differs by sex. Thus, we performed a systematic review to address the relationship between sex and SAH CFRs. METHODS: We conducted a systematic literature search in PubMed, Scopus, and Cochrane library databases. We focused on population-based studies that included both non-hospitalized and hospitalized SAHs and had either reported 1-month (28-31 day) SAH CFRs separately for men and women or calculated risk estimates for SAH CFR by sex. For quality classification, we used the Cochrane Collaboration Handbook and Critical Appraisal Skills Program guidelines. We pooled the study cohorts and calculated relative risk ratios (RR) with 95 % confidence intervals (CIs) for SAH death between women and men using a random-effects meta-analysis model. RESULTS: The literature search yielded 5,592 initial publications, of which 33 study cohorts were included in the final review. Of the 33 study cohorts, only three reported significant sex differences, although the findings were contradictory. In the pooled analysis of all 53,141 SAH cases (60.3 % women) from 26 countries, the 1-month CFR did not differ (RR = 0.99 [95 % CI 0.93-1.05]) between women (35.5 %) and men (35.0 %). According to our risk-of-bias evaluation, all 33 study cohorts were categorized as low quality. The most important sources of bias risks were related to the absence of proper confounding control (all 33 study cohorts), insufficient sample size (27 of 33 study cohorts), and poor/unclear diagnostic accuracy (27 of 33 study cohorts). CONCLUSION: Contrary to SAH incidence rates, the SAH CFRs do not seem to differ between men and women. However, since none of the studies were specifically designed to examine the sex differences in SAH CFRs, future studies on the topic are warranted.

Case Fatality of Aneurysmal Subarachnoid Hemorrhage Varies by Geographic Region Within Finland: A Nationwide Register-Based Study.

BACKGROUND AND OBJECTIVES: Previous studies have reported a substantial between-country variation in the case fatality rates (CFRs) of aneurysmal subarachnoid hemorrhage (SAH). However, contrary to comparisons among countries, nationwide comparisons within countries that focus on populations with equal access to health care and include out-of-hospital deaths in analyses are lacking. Thus, we aimed to investigate whether the SAH CFRs vary between geographic regions within Finland. METHODS: We identified all hospitalized and nonhospitalized (sudden-death) cases with aneurysmal SAH in Finland during 1998-2017 through 2 externally validated nationwide registers. According to the municipality of residence, we divided the cases with SAH into 5 geographic regions: Southern, Central, Western, Northern, and Eastern Finland, each served by a University Central Hospital with a neurosurgical service. In addition to overall 30-day CFRs, we computed sudden death rates and 30-day CFRs after hospitalization for each region. Using logistic and Poisson regression models, we calculated regional age-adjusted, sex-adjusted, and year-adjusted odds ratios and annual percent changes with 95% CIs for CFRs. RESULTS: During 1998-2017, we identified a total of 9,443 cases with SAH, of which 3,484 (36.9%) occurred in Southern Finland. In comparison with the overall 30-day CFR of Southern Finland (35.1%), the age-adjusted, sex-adjusted, and study year-adjusted odds of SAH death were 32% (16%-50%) higher in Central Finland (42.7%), 39% (23%-58%) higher in Eastern Finland (43.4%), and 52% (33%-74%) higher in Western Finland (47.1%). The regional differences were present among both sexes, in all age groups, in sudden death rates, and in 30-day CFRs after hospitalization. Between 1998 and 2017, the overall 30-day CFRs decreased in Central (2.4% [1.0%-3.8%] per year) and Southern (1.2% [0.2%-2.2%] per year) Finland, whereas CFRs remained stable in the other regions. In the last 4 years of the study period (2014-2017), Southern Finland had the lowest 30-day CFR (16.5%) among hospitalized patients. DISCUSSION: SAH CFRs seem to vary significantly even within a country with relatively equal access to health care. Future studies with detailed individual-level data are needed to explore whether health inequities explain the reported findings.

Case Fatality in Patients With Aneurysmal Subarachnoid Hemorrhage in Finland: A Nationwide Register-Based Study.

BACKGROUND AND OBJECTIVES: Although single-center studies have reported declining case fatality rates (CFRs) of aneurysmal subarachnoid hemorrhage (SAH), nationwide reports that also include sudden-death SAHs with long uninterrupted study periods have remained limited. Moreover, little is known about whether the time-dependent trends of SAH CFR differ by age and/or sex. Thus, we aimed to characterize the nationwide changes of SAH CFRs in Finland between 1998 and 2017. METHODS: We used 2 externally validated nationwide registers to identify all hospitalized and nonhospitalized (sudden-death) aneurysmal SAH events in Finland during 1998-2017. In addition to overall 30-day CFRs, we determined annual proportions of sudden-death and 30-day CFRs among hospitalized patients with SAH. To estimate time-dependent trends, we calculated annual age-adjusted and sex-adjusted CFR changes (percent with 95% CIs). RESULTS: Between 1998 and 2017, we identified 9,443 cases with SAH (57.6% women), of which 2,245 (23.8%) died before hospitalization and 3,715 (39.3%) died within 30 days after SAH. Among the 7,198 hospitalized patients with SAH, the 30-day CFR was 20.4%. During the study period, the overall age-adjusted and sex-adjusted CFR declined by an average of 1.8% (1.1%-2.6%) per year. The decreases were especially notable in the proportion of sudden deaths among middle-aged (aged 40-64 years) and older (aged 65 years or older) women (2.9% [1.1%-4.7%] and 2.3% [0.7%-4.0%] per year, respectively) and in the CFRs of hospitalized young (younger than 40 years) and middle-aged women (9.1% [2.3%-15.7%] and 4.3% [2.3%-6.5%] per year, respectively). On the contrary, the 30-day CFR of older (aged 65 years or older) hospitalized men increased by 3.5% (0.7%-6.3%) per year, while the proportions of older men who died before hospitalization remained unchanged. DISCUSSION: The overall CFR of SAH seems to be decreasing, at least among women. The continued high CFR of hospitalized older men requires attention from clinicians and epidemiologists, especially if this trend is also common in other countries.