Table 1

Relationship between serum bilirubin and ischaemic stroke outcomes

Study	Outcomes reported									Major findings
Study	Outcome 1	Unit	Follow-up point (days)	Outcome 2	Unit	Follow-up point (days)	Outcome 3	Unit	Follow-up point (days)	Major findings
Bhatia et al 65	Death	Mortality	30							Bilirubin did not differ significantly in the survivors and expired stroke patients.
Perlstein et al 35	Adverse stroke outcomes	A ‘Physical Function’ questionnaire	1							Higher TBIL level is associated with improved stroke outcomes.
Pineda et al 61	Neurological impairment	NIHSS score	1	Death or disability	mRS	At discharge	Poor functional outcome	mRS score >3	At discharge	Higher DBIL level is associated with greater stroke severity but not functional outcome among ischaemic stroke patients.
Kurzepa et al 54	Functional disability	BI score	90	Neurological impairment	NIHSS score	1, 3, 5 and 10				Serum bilirubin levels are poor prognostic factors for ischaemic stroke.
Arsalan et al 53	Neurological impairment	NIHSS score	7.25 (at discharge)	Death or disability	mRS	7.25 (at discharge)	Poor functional outcome	mRS score was from 4 to 6	7.25 (at discharge)	Higher serum bilirubin levels were associated with increased stroke severity, longer hospitalisation and poor prognosis.
Luo et al 57	Neurological impairment	NIHSS score	1	Relative severe stroke	NIHSS score ≥8	1				Serum bilirubins were in significant correlation with severity of AIS.
Luo et al 3	Neurological impairment	NIHSS score	1	Relative severe stroke	NIHSS score ≥8	1				The serum levels of DBIL and TBIL were increased after AIS, which linked to the severity of stroke.
Markaki et al 60	Death	Mortality	28 months							Bilirubin is an independent predictor of mortality in ischaemic cerebrovascular disease patients (ischaemic stroke and transient ischaemic attack).
Xu et al 58	Neurological impairment	NIHSS score	1	Higher severity	NIHSS score ≥10	1	Short-term clinical outcomes	NIHSS ≥10 at discharge or in-hospital death	At discharge	Serum bilirubin levels were associated with initial stroke severity closely but not short-term clinical outcomes among AIS patients.
Ademiluyi et al 56	Neurological impairment	NIHSS score	1	Severe stroke	NIHSS score >14	1				AIS patients with higher physiological range of serum bilirubin had more severe stroke (higher NIHSS values).
Sagheb Asl et al 59	Death	Mortality	14							TBIL, DBIL and IBIL levels were significantly associated with mortality in AIS patients.
Wang et al 55	Neurological impairment	NIHSS score	1, 7 and 14	Disability	mRS	30	Poor functional outcome	mRS score >3	30	Hyperbilirubinaemia might be a biomarker for a poor prognosis in the early identification of LAA strokes.

AIS, acute ischaemic stroke; BI, Barthel Index; DBIL, direct bilirubin; IBIL, indirect bilirubin; LAA, large-artery atherosclerosis; mRS, modified Rankin Scale; NIHSS, National Institutes of Health Stroke Scale; TBIL, total serum bilirubin.