Table 4.

SAH coil embolisation volumes immediately before and during the COVID-19 pandemic

	Overall volume						Monthly volume
	N	n1	n2	Relative (%) change	P value	N	Immediately before n=1670	During COVID-19 n=1075	Difference* (95% CI)	P value
				% (95% CI)			Median (IQR)
Overall	125	1170	1035	−11.5 (−13.5 to −9.8)	0.002	133	1.8 (1.0–4.0)	1.7 (0.67–3.3)	−0.25 (−0.58 to −0.08)	0.0004
Hospital COVID-19 volume†
Low	39	270	266	−1.5 (−3.7 to −0.58)	0.764	40	1.5 (0.88–2.5)	1.0 (0.50–2.8)	−0.29 (−0.67 to 0.08)	0.294
Int	33	319	287	−10.0 (−13.8 to −7.2)	0.151	35	2.5 (1.0–3.8)	2.0 (1.0–3.0)	−0.25 (−0.75 to 0.0)	0.041
High	31	329	256	−22.2 (−27.0 to −18.0)	0.002	34	2.0 (1.3–5.0)	2.0 (1.0–4.0)	−0.63 (−1.2 to 0.0)	0.007
Hospital SAH Coil embolisation volume‡
Low	46	107	151	41.1 (32.3 to 50.6)	0.008	49	0.75 (0.25–1.0)	0.67 (0.33–1.7)	0.0 (0.0 to 0.33)	0.044
Int	37	217	192	−11.5 (−16.5 to −7.9)	0.178	39	2.0 (1.8–2.5)	1.3 (0.67–2.7)	−0.75 (−1.1 to −0.08)	0.015
High	42	846	692	−18.2 (−20.9 to −15.8)	<0.0001	45	5.3 (4.0–8.8)	4.7 (2.7–6.3)	−1.8 (−2.3 to −0.67)	<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≤0.0001, low versus high≤0.0001, Int versus high≤0.0001.

‡P value: low versus Int=n/a; low versus high=n/a; Int versus high=0.019.

Int, intermediate; N, number of hospitals; n, number of procedures; n/a, not applicable; SAH, subarachnoid haemorrhage.