Table 1

SAH hospitalisation volumes immediately before and during the COVID-19 pandemic

	Overall volume						Monthly volume
	N	n1	n2	Relative (%) change	P value	N	Immediately before n=2838	During COVID-19 n=1645	Difference* (95% CI)	P value
				% (95% CI)			Median (IQR)
Overall	118	2044	1585	−22.5 (−24.3 to −20.7)	<0.0001	124	4.5 (2.5–7.1)	3.3 (1.3–6.3)	−0.88 (−1.1 to −0.58)	<0.0001
Hospital COVID-19 volume†
Low	32	432	367	−15.1 (−18.7 to −12.0)	0.014	33	3.5 (2.5–6.5)	3.3 (1.7–6.0)	−0.83 (−1.9 to 0.50)	0.076
Int	32	589	458	−22.2 (−25.8 to −19.1)	<0.0001	34	4.9 (3.5–6.8)	3.7 (1.7–6.0)	−0.83 (−1.9 to −0.17)	0.001
High	33	731	513	−29.8 (−33.2 to −26.6)	<0.0001	36	6.0 (3.0–8.4)	4.2 (2.2–7.2)	−1.0 (−2.0 to −0.67)	<0.0001
Hospital SAH coil embolisation volume‡
Low	42	370	293	−20.8 (−25.2 to −17.0)	0.002	45	2.5 (1.3–3.8)	2.0 (1.0–3.3)	−0.25 (−0.75 to 0.08)	0.141
Int	35	490	385	−21.4 (−25.3 to −18.0)	0.0002	36	4.4 (2.9–5.6)	3.0 (1.5–4.7)	−1.0 (−1.5 to −0.17)	0.007
High	35	1014	783	−22.8 (−25.5 to −20.3)	<0.0001	36	7.3 (5.9–11.6)	6.7 (4.0–9.3)	−2.0 (−3.1 to −0.75)	<0.0001

n1 is based on 3 months before the pandemic (December 2019–February 2020). Immediately before is based on 4 months before the pandemic (November 2019–February 2020). n2 and during COVID-19 are based on March 2020–May 2020.
P value is from Poisson means test (overall volume analysis) and Wilcoxon signed-rank test (monthly volume analysis).
*Difference denotes the median difference between the two time periods.
†P value: low versus Int=0.004, low versus high=<0.0001, Int versus high=0.002.
‡P value: low versus Int=0.831, low versus high=0.429, Int versus high=0.541.
Int, intermediate; N, number of hospitals; n, number of admissions; SAH, subarachnoid haemorrhage.