Table 1.

Characteristics and details of the included studies.

Ref.	Sample size (example)		Intervention		Age		Diagnostic criteria
	T	C	T	C	T	C
Sultan et al[16], 2010	53	49	Melatonin	Placebo	70.4 ± 7.1	72.3 ± 6.4	CAM
de Jonghe et al[17], 2014	186	192	Melatonin	Placebo	84.1 ± 8.0	83.4 ± 7.5	CAM
Wang et al[18], 2018	30	30	Melatonin	Placebo	70.7 ± 4.3	69.9 ± 4.5	CAM
Prabhat et al[19], 2019	50	50	Melatonin	Placebo	69.30 ± 4.05	70.64 ± 3.76	CAM
Ford et al[20], 2018	98	104	Melatonin	Placebo	69 ± 8.3	67.6 ± 8.0	CAM
Chen et al[21], 2020	45	45	Melatonin	Placebo	71.36 ± 7.12	73.56 ± 6.65	CAM
Javaherforoosh Zadeh et al[22], 2019	30	30	Melatonin	Placebo	60.26 ± 9.50	62.9 ± 8.08	CAM
Oh et al[23], 2020	33	38	Melatonin	Placebo	71.3 ± 5.1	71.6 ± 5.2	CAM
Al-Aama et al[24], 2010	61	61	Melatonin	Placebo	84.3 ± 5.9	84.6 ± 6.2	CAM
Hatta et al[25], 2014	33	34	Melatonin	Placebo	78.2 ± 6.6	78.3 ± 6.8	CAM
Agar et al[26], 2016	14	16	Melatonin	Placebo	76.3 ± 5.6	76.0 ± 5.3	CAM
Jaiswal et al[27], 2018	36	33	Melatonin	Placebo	75.3 ± 5.3	75.6 ± 5.7	CAM
Lawlor et al[28], 2020	30	30	Melatonin	Placebo	67 ± 5.9	67 ± 6.0	CAM
Mengel et al[29], 2021	164	164	Melatonin	Placebo	74 ± 1.3	73 ± 1.5	CAM
Vijayakumar et al[30], 2015	26	30	Melatonin	Placebo	36.9 ± 10.3	38 ± 14.4	CAM
Nishikimi et al[31], 2017	45	43	Melatonin	Placebo	68.0 ± 5.1	68.0 ± 5.3	CAM
Abbasi et al[32], 2018	67	70	Melatonin	Placebo	52.5 ± 18.4	49.9 ± 19	CAM
Jaiswa et al[33], 2019	59	58	Melatonin	Placebo	58.1 ± 14.1	56.1 ± 15.8	CAM

T: Experimental group; C: Control group; CAM: Delirium confusion assessment method standard determination.