Table 4

SAH in-hospital mortality rate 1 year previously compared with 1 year during the COVID-19 pandemic

	N	Overall volume
	N	aSAH admissions	Mortality	Mortality rate (%)	P value
Overall
Before COVID	144	5918	1129	19.08	0.12
During COVID	144	5654	1181	20.89
Hospital aSAH volume: low
Before COVID	46	325	94	28.92	0.936
During COVID	46	377	108	28.65
Hospital aSAH volume: medium
Before COVID	51	1402	310	22.11	0.678
During COVID	51	1407	302	21.46
Hospital aSAH volume: high
Before COVID	47	4191	725	17.30	0.003
During COVID	47	3870	771	19.90
Centre COVID-19 volume: low
Before COVID	47	1772	293	16.53	0.872
During COVID	47	1812	296	16.34
Centre COVID-19 volume: intermediate
Before COVID	42	1421	296	20.83	0.116
During COVID	42	1334	311	23.31
Centre COVID-19 volume: high
Before COVID	41	2035	445	21.87	0.003
During COVID	41	1907	495	25.96

The periods before and during COVID-19 pandemic were defined as 12 months before and during the COVID-19 pandemic, respectively.
aSAH, aneurysmal subarachnoid haemorrhage; n, number of hospitals; SAH, subarachnoid haemorrhage.