Table 4.
Quality appraisal of included studies (n = 37)
| Citation | Positive association ✔ or X | Sampling approach (score range: 0–1) | Confounding variables (score range: 0–2) | Response rate (score range: 0–2) | Validity of social connectedness measure (score range: 0–2) | Validity of outcome measure (score range: 0–2) | Total score Total score divided by total maximum score (9) |
Risk of bias |
|---|---|---|---|---|---|---|---|---|
| Achille & Ogloff (2004) [68] | ✔ | 0 | 0 | 2 (77%) | 2 | 1 | 56% | Medium |
| Arnold (2004) [69] | ✔ | 0 | 1 | 0 | 2 | 0 | 33% | High |
| Berkman et al. (1999) [67] | ✔ | 1 | 0 | 1 (34–36%) | 2 | 0 | 44% | Medium |
| Blank et al. (2001) [70] | X | 0 | 1 | 1 (48%) | 0 | 0 | 22% | High |
| Breitbart et al. (1996) [71] | X | 0 | 1 | 0 | 2 | 1 | 44% | Medium |
| Breitbart et al. (2000) [22] | ✔ | 0 | 2 | 1 (22%) | 2 | 2 | 78% | Low |
| Buiting et al. (2012) [63] | X | 1 | 0 | 2 (69%) | 2 | 0 | 56% | Medium |
| Cheung et al. 2020 [78] | X | 1 | 0 | 1 (100%; analysis of routine clinical records) | 1 | 0 | 33% | High |
| Chochinov (1995) [79] | X | 0 | 1 | 1 (23%) | 0 | 2 | 44% | Medium |
| Cicirelli (1997) [64] | X | 0 | 2 | 0 | 2 | 0 | 44% | Medium |
| Comby & Filbet (2005) [56] | X | 0 | 0 | 1 (100% but very small sample) | 0 | 1 | 22% | High |
| Emanuel et al. (2000) [13] | X | 0 | 0 | 2 (87%) | 2 | 0 | 44% | Medium |
| Ganzini et al. (1998) [72] | X | 0 | 0 | 2 (71%) | 2 | 0 | 44% | Medium |
| Ganzini et al. (2006) [57] | X | 0 | 0 | 1 (44%) | 2 | 0 | 33% | High |
| Ganzini et al. (2008) [58] | X | 0 | 0 | 1 (38%) | 0 | 2 | 33% | High |
| Ganzini et al. (2009) [59] | X | 0 | 0 | 1 (31%) | 0 | 0 | 11% | High |
| Himchak (1997) [73] | X | 0 | 2 | 0 | 2 | 1 | 56% | Medium |
| Kelly et al. (2003) [80] | ✔ | 0 | 2 | 1 (49%) | 2 | 1 | 67% | Low |
| Lulé et al. (2014) [74] | X | 0 | 1 | 0 | 2 | 2 | 56% | Medium |
| Marrie et al. (2017) [75] | X | 0 | 1 | 2 (70%) | 2 | 0 | 56% | Medium |
| O’Mahony (2005) [23] | ✔ | 0 | 0 | 1 (49%) | 2 | 2 | 56% | Medium |
| O’Mahony (2010) [81] | ✔ | 0 | 1 | 1 (49%) | 2 | 1 | 56% | Medium |
| Pacheco et al. (2003) [76] | X | 0 | 0 | 2 (79%) | 1 | 0 | 33% | High |
| Rodin et al. (2007) [82] | X | 1 | 2 | 1 (59%) | 2 | 2 | 89% | Low |
| Rosenfeld et al. (2000) [83] | X | 0 | 0 | 2 (60%) | 2 | 2 | 67% | Low |
| Rosenfeld et al. (2006) [84] | X | 1 | 2 | 2 (87%) | 2 | 2 | 100% | Low |
| Rosenfeld et al. (2014) [85] | X | 0 | 2 | 1 (13%) | 2 | 2 | 78% (7/9) | Low |
| Ruijs et al. (2014) [53] | X | 0 | 0 | 1 (51%) | 1 | 2 | 44% | Medium |
| Schroepfer (2008) [62] | ✔ | 0 | 2 | 0 | 0 | 0 | 22% | High |
| Seidlitz et al. (1995) [66] | X | 1 | 1 | 0 | 0 | 0 | 22% | High |
| Smith et al. (2011) [52] | X | 0 | 0 | 1 (38%) | 1 | 2 | 44% | Medium |
| Smith et al. (2015) [60] | X | 0 | 0 | 0 | 2 | 2 | 44% | Medium |
| Snijdewind et al. (2015) [11] | ✔ | 1 | 0 | 2 (91%) | 0 | 2 | 56% | Medium |
| Stolz et al. (2017) [65] | ✔ and X | 1 | 2 | 2 (85%) | 1 | 0 | 67% | Low |
| Stutzki et al. (2014) [77] | ✔ | 1 | 0 | 1 (50%) | 0 | 0 | 22% | High |
| Virik & Glare (2002) [55] | X | 0 | 0 | 1 (100% but very small sample size) | 0 | 2 | 33% | High |
| Wilson et al. (2007) [61] | ✔ | 1 | 0 | 1 (41%) | 1 | 0 | 33% | High |
Footnote: Grading of the adapted QATSO scores was as follows: 0% -33% = low quality i.e., high risk of bias; 34%- 66% = medium quality i.e., medium risk of bias; 67% -100% = high quality i.e., low risk of bias