Case Fatality of Aneurysmal Subarachnoid Hemorrhage Varies by Geographic Region Within Finland

Abstract

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 healthcare 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 non-hospitalized (sudden-death) aneurysmal SAH cases in Finland during 1998-2017 via two externally validated nationwide registers. According to the municipality of residence, we divided the SAH cases into five 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-, sex-, and year-adjusted odds ratios and annual percent changes with 95% confidence intervals for CFRs.Results:During 1998-2017, we identified a total of 9 443 SAH cases, of which 3 484 (36.9%) occurred in Southern Finland. In comparison to the overall 30-day CFR of Southern Finland (35.1%), the age-, sex-, 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, and in sudden death rates as well as 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 four years of the study period (2014-2017), Southern Finland had the lowest 30-day CFR (16.5%) among hospitalized patients.Discussion:SAH CFRs appear to vary significantly even within a country with relatively equal access to healthcare. Future studies with detailed individual-level data are needed to explore whether health inequities explain the reported findings.

Fresh Insights Into Variable Mortality From Subarachnoid Hemorrhage Across Regions of Finland

“…The most obvious one, that of differences in access to hospital care or state-of-the-art management strategies across regions, seems most unlikely given the ready access of the population to advanced health care in Finland. Moreover, acute phase transfer of care for critical conditions across regions rarely occurs in Finland, 5 and the temporal trends applied to all deaths from SAH, both within and outside hospital. This leads one to consider the influence of regional differences in risk factors for SAH.…”

“…Substantial geographic variability in the incidence of SAH has also been noted across the country, with associations in relation to age, sex, and risk factors. 4 In this issue of Neurology ®, Asikainen et al 5 publish a study in which they extend their prior observations into an analysis of regional differences in deaths from SAH in Finland.…”

“…Using administrative data from 2 registries, the Case Register for Health Care and the National Cause of Death Register, the authors identified a total of 9,443 first-ever nonfatal and fatal cases of SAH in Finland during a period of almost 20 years (1998–2017). 5 The unique ability to identify a high proportion (24%) of out-of-hospital sudden deaths from SAH was made possible by the government's legislation which requires postmortem examinations to be performed on all sudden deaths that occur outside hospital facilities. The key finding was a highly variable 30-day case fatality ratio across the 5 geographic regions (that is, Northern, Southern, Western, Eastern, Central) of Finland, where each is served by a University Central Hospital with neurosurgical and neurointerventional expertise in a country with a relatively homogeneous population and high standard of public access to health care.…”