Table 1.
General characteristics of included studies (N=26)
| Characteristics | Number, n | Percentage |
| Publication year | ||
| 2000–2004 | 4 | 15.4 |
| 2005–2009 | 4 | 15.4 |
| 2010–2015 | 18 | 69.2 |
| Location of the study | ||
| Australia | 5 | 19.2 |
| Canada | 2 | 7.7 |
| Finland | 1 | 3.8 |
| Iran | 1 | 3.8 |
| Netherlands | 1 | 3.8 |
| New Zealand | 1 | 3.8 |
| Sweden | 1 | 3.8 |
| Switzerland | 1 | 3.8 |
| Taiwan | 3 | 11.5 |
| UK | 6 | 23.1 |
| USA | 4 | 15.4 |
| Study design | ||
| Cross-sectional | 11 | 42.3 |
| Randomised controlled trial | 8 | 30.8 |
| Cohort | 1 | 3.8 |
| Phenomenological | 4 | 15.4 |
| Observational | 1 | 3.8 |
| Mixed method | 1 | 3.8 |
| Elective surgery specialty* | ||
| General surgery | 10 | 37 |
| Ophthalmology | 0 | 0 |
| Neurosurgery | 0 | 0 |
| Orthopaedics | 10 | 37 |
| ENT | 1 | 3.7 |
| Urology | 1 | 3.7 |
| Gynaecology | 0 | 0 |
| Bariatric/cosmetic/plastic surgery | 3 | 7.4 |
| Thoracic surgery | 1 | 3.7 |
| Craniofacial surgery | 0 | 0 |
| Cancer-related surgery | 1 | 3.7 |
*There were no studies reporting ophthalmology, neurosurgery, gynaecology, thoracic surgery or craniofacial surgery. One study included urological and general surgery.
ENT, ear, neck and throat.