Table 1.
An overview of the included systematic reviews showing the review objective and geographical locations where the reviews of primary studies were conducted
| First author (year) | Period of review | Research setting | Number of primary studies included | Number of primary studies describing nurse staffing levels and patient outcomes in non-ICU settings* | Geographical locations of studies and frequency | Number of low/middle-income countries included (%) | Number of high-income countries included (%) |
| Griffiths (2018)10 | 2006–2016 | Adult hospital inpatient wards | 18 | 17 | Kuwait: 1, Europe: 3, UK: 1, Sweden: 1, USA†: 7, Lebanon†: 1, Switzerland: 1, Italy: 1, South Korea: 2 | 1 (5.6) | 17 (95.4) |
| Assaye (2020)22 | UR– 2019 | Acute care hospital settings | 27 | 6 | Brazil: 1, Thailand: 2, China: 1, Ethiopia: 1, Lebanon: 1 | 6 (100.0) | 0 (0.0) |
| Thungjaroenkul (2007)40 | 1990–2006 | ICUs, medical and surgical units | 17 | 5 | USA: 5 | 0 (0.0) | 5 (100.0) |
| Twigg (2021)19 ‡ | 2000–2020 | General medical, surgical, step-down units, emergency departments, intensive care and nursing homes | 22 | 7 | USA: 6, Australia: 1 | 0 (0.0) | 7 (100.0) |
| Shin (2019)43 | 2000–2018 | Medical and surgical units | 19 | 17 | USA: 10, South Korea: 2, Finland†: 1, Netherlands†: 1, Lebanon: 1, Belgium: 1, China: 1, Japan: 1 |
2 (11.1) | 16 (88.9) |
| Lang (2004)‡ | 1980–2003 | Acute care hospitals | 43 | 24 | USA: 24 | 0 (0.0) | 24 (100.0) |
| Lankshear (2005)42 | 1990–2004 | Acute care hospitals | 22 | 19 | USA: 18, Canada: 1 | 0 (0.0) | 19 (100.0) |
| Kane (2007)14 | 1990–2006 | Acute care hospitals | 28 | 17 | USA: 17 | 0 (0.0) | 17 (100.0) |
| Bourgon (2019)38 | 1996–2018 | Surgical units | 44 | 28 | USA: 17, Europe: 2, South Korea: 1, UK: 2, New Zealand: 1, Australia: 2, Belgium: 2, Japan: 1 | 0 (0.0) | 28 (100.0) |
| Wilson (2011)39 | 1993–2010 | Paediatric wards | 8 | 5 | USA: 2, France: 1, Canada: 1, UK: 1 | 0 (0.0) | 5 (100.0) |
| Engineer (2016)41‡ | 2000–2012 | Acute care hospitals | 16 | 2 | USA: 2 | 0 (0.0) | 2 (100.0) |
| Stalpers (2015)36 | 2004–2012 | Acute care hospitals | 29 | 16 | USA†: 12, Belgium†: 1, New Zealand: 1, Australia: 1, UK: 1, Sweden: 1 |
0 (0.0) | 17 (100.0) |
| Mitchell (2018)28 | 2000–2015 | Hospital wards | 54 | 19 | USA: 13, Thailand: 1, Australia: 1, Taiwan: 1, Canada:2, multicountry: 1 |
1 (4.3) | 18 (95.7) |
| Hill (2017)37 | 1994–2017 | Acute care hospitals | 5 | 5 | USA: 3, UK: 2 | 0 (0.0) | 5 (100.0) |
*These are the number of studies that met the original review criteria, that is, conducted in a regular ward setting on the role of nurse staffing and patient care outcomes.
†One study conducted across both countries.
‡Restricted search criteria to high-income countries.
ICU, intensive care unit; UR, unreported.