Table 3

(A) Endovascular coiling admissions overall, monthly volumes before and during the COVID-19 pandemic, and (B) surgical clipping admissions overall and monthly volumes before and during the COVID-19 pandemic

(A)
	N	Overall volume				Monthly volume*
		n1	n2	Change	P vaue	N	Before COVID-19	During COVID-19	P value
		n1	n2	% (95% CI)	P vaue	N	Adjusted mean (SE)
Overall	152	3464	3374	−2.6 (−3.2 to −2.1)	0.276	166	2.06 (0.44)	2.02 (0.43)	0.518
Hospital endovascular coiling volume stratified by prepandemic aSAH volume††
Low	42	183	231	26.2 (20.4 to 33.1)	0.019	47	0.35 (0.09)	0.45 (0.10)	0.058
Int.	54	842	813	−3.4 (−4.9 to −2.4)	0.476	56	1.28 (0.15)	1.26 (0.15)	0.783
High	50	2240	2135	−4.7 (−5.7 to −3.9)	0.112	55	4.13 (0.82)	3.97 (0.81)	0.269
Hospital endovascular coiling volume stratified by hospital COVID-19 volume‡‡
Low	45	851	870	2.2 (1.4 to 3.5)	0.647	49	1.44 (0.46)	1.48 (0.45)	0.729
Int.	42	798	828	3.8 (2.7 to 5.3)	0.457	45	1.35 (0.45)	1.41 (0.44)	0.495
High	44	1047	990	−5.4 (−7.0 to −4.2)	0.207	48	2.12 (0.78)	2.0 (0.78)	0.273

(B)
	N	Overall volume				Monthly volume*
		n1	n2	Change	P value	N	Before COVID-19	During COVID-19	P value
		n1	n2	% (95% CI)	P value	N	Adjusted mean (SE)
Overall	140	1848	1676	−9.3 (−10.7 to −8.1)	0.004	151	1.29 (0.42)	1.18 (0.43)	0.067
Hospital clipping volume stratified by prepandemic aSAH volume§§
Low	40	91	101	11.0 (6.1 to 19.1)	0.471	45	0.13 (0.05)	0.14 (0.06)	0.616
Int.	50	350	368	5.1 (3.3 to 8.0)	0.502	51	0.61 (0.11)	0.63 (0.12)	0.826
High	47	1392	1202	−13.6 (−15.6 to −12.0)	0.0002	51	2.65 (0.90)	2.32 (0.93)	0.034
Hospital clipping volume stratified by hospital COVID-19 volume ¶¶
Low	45	650	672	3.4 (2.2 to 5.1)	0.545	47	0.40 (0.68)	0.44 (0.72)	0.655
Int	37	411	387	−5.8 (−8.5 to −4.0)	0.396	41	0.68 (0.46)	0.63 (0.48)	0.308
High	42	519	401	−22.7 (−26.5 to −19.3)	0.0001	44	1.16 (0.29)	0.89 (0.23)	0.102

*The monthly volume analysis is adjusted for the date of peak COVID-19 volume for each country, the start date of the second wave, and the continent.
†P value: low versus int.=N/A, low versus high=N/A, int. versus high=0.115.
‡P value: low versus int.=0.056, low versus high=N/A, int. versus high=N/A.
§P value: low versus int.=0.040, low versus high=N/A, int. versus high=N/A.
¶P value: low versus int.=N/A, low versus high=N/A, int. versus high≤0.0001.
aSAH, aneurysmal subarachnoid haemorrhage; int., intermediate; n1, number of admissions during 12 months before COVID-19 pandemic; n2, number of admissions during 12 months of COVID-19 pandemic; N/A, not applicable; n, number of hospitals; SAH, subarachnoid haemorrhage.