Table 1.
Characteristics of the Studies
| Study (Country) | Participants (the Type of Surgery) | Sample Size, Gender, Age (Melatonin/Placebo) | Interventions (Daily Dose, Route of Administration, Time) | Outcomes |
|---|---|---|---|---|
| Andersen 201424 (Denmark) | LC | MEL: 20, all female, 57 (23–69) PLA: 21, all female, 45 (20–67) Data are median and range |
MEL-10mg (25 mL ethanol/saline solution containing 10 mg of melatonin), intravenous infusion, the time of surgical incision |
VAS |
| Borazan 201020 (Turkey) | Prostatectomy | MEL: 26, all male, 57 ± 7 PLA: 26, all male, 58 ± 6 Data are mean ± SD |
MEL tablet-6mg, oral, PERD1 (11 p.m.) and 1 h before surgery |
Incidence of poor sleep quality |
| Fan 201719 (China) | Hip arthroplasty | MEL: 69, 25 male/44 female, 74.6 ± 5.4 PLA: 70, 28 male/42 female, 74.5 ± 5.7 Data are mean ± SD |
MEL preparation-1mg, oral, PERD1 (1 h before sleep) and POD1-5 |
VAS |
| Gögenur 200925 (Denmark) | LC | MEL: 60, 19 male/41 female, 44 ± 13 PLA: 61, 16 male/45 female, 47 ± 12 Data are mean ± SD |
MEL capsule-5mg, oral, 30 min before sleep in POD1-3 |
VAS SL, TST, number and duration of awakenings, number and duration of daily naps |
| Hansen 201427 (Denmark) | Breast cancer surgery | MEL: 28, all female, 51 (46–66) PLA: 26, all female, 60 (49–68) Data are median and 25–75% IQR |
MEL tablet-6mg, oral, 1 h before sleep from PERD7 to 12 weeks after surgery |
VAS SE |
| Kirksey 201523 (USA) | Knee arthroplasty | MEL: 19, 5 male/14 female, 70 ± 9.3 PLA: 18, 12 male/6 female, 61.4 ± 14.3 Data are mean ± SD |
MEL tablet-5mg, oral, shortly before sleep for 7 days from PERD3 to POD3 |
SQS |
| Madsen 201626 (Denmark) | Breast cancer surgery | MEL: 27, all female, 51 (38–74) PLA: 21, all female, 59 (34–74) Data are median and range |
MEL tablet-6mg, oral, 1 h before sleep from PERD3 to 12 weeks after surgery |
VAS SL, TST, SE, number of awakenings, number of daily naps |
| Samarkandi 200531 (Saudi Arabia) | Minor elective surgery (inguinal hernia, undescended testis, hydrocoele and hypospadias) |
MEL1: 15, 8 male/7 female, 3.9 (3.1–4.6) MEL2: 15, 9 male/6 female, 3.7 (3–4.3) MEL3: 15, 12 male/3 female, 3.1 (2.7–3.6) PLA: 15, 9 male/6 female, 3.6 (2.9–4.2) Data are median and 25–75% IQR |
MEL1: 0.1mg/kg MEL2: 0.25mg/kg MEL3: 0.5mg/kg, oral, 1 h before surgery |
Incidence of sleep disorders |
| Seet 201532 (Singapore) | Wisdom teeth extraction | MEL: 36, 24 male/12 female, 22.7 ± 2.2 PLA: 37, 23 male/14 female, 23.0 ± 2.8 Data are mean ± SD |
MEL tablet-6mg, oral, 90 min before surgery |
VAS |
| Vij 201830 (India) | LC | MEL: 50, 13 male/37 female, 42.8 ± 9.81 PLA: 50, 9 male/41 female, 41.4 ± 10.85 Data are median ± SD |
MEL tablet-3mg*2, oral, 45 min before sleep for POD1-3 |
VAS SL, TST, number and duration of awakenings, number and duration of daily naps |
Note: Comparisons were all placebo and not listed in Table 1.
Abbreviations: LC, laparoscopic cholecystectomy; MEL, melatonin; PLA, placebo; SD, standard deviation; IQR, interquartile range; PERD1, 1 day before surgery; PERD3, 3 days before surgery, PERD7, 7 days before surgery; POD3 3 days after surgery; POD1-3, 1 to 3 days after surgery; POD1-5, 1 to 5 days after surgery; SL, sleep latency; TST, total sleep time; SE, sleep efficiency.