Table 3.

IRR of ischaemic stroke following COVID-19 in the SCCS

	Number of events	IRR (95% CI)	p value
Ischaemic stroke analysis 1 (day 0 out of the risk period)
Control period	123	1 (ref)	..
Buffer period: days −28 to −4	57	1·95 (1·25–3·04)	0·0031
Pre-exposure period: days −3 to 0	33	11·28 (7·15–17·80)	<0·0001
Risk period: days 1 to 7	16	2·97 (1·71–5·15)	0·0001
Risk period: days 8 to 14	14	2·80 (1·60–4·88)	0·0003
Risk period: days 15 to 28	11	2·10 (1·33–3·32)	0·0015
Ischaemic stroke analysis 2 (day 0 in the risk period)
Control period	123	1 (ref)	..
Buffer period: days −28 to −4	57	1·89 (1·21–2·96)	0·0048
Pre-exposure period: days −3 to −1	8	3·96 (1·85–8·45)	0·0004
Risk period: days 0 to 7	41	6·18 (4·06–9·42)	<0·0001
Risk period: days 8 to 14	14	2·85 (1·64–4·97)	0·0002
Risk period: days 15 to 28	11	2·14 (1·36–3·38)	0·0011

IRR=incidence rate ratio. SCCS=self-controlled case series.