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Table 3 Quality assessment summary clustered by research design

From: Impact of contextual factors on patient outcomes following conservative low back pain treatment: systematic review

Reference (year) Quality of reporting
(10 items)
Range: 0–11 points
External validity
(3 items)
Range: 0–3 points
Internal validity
(7 items)
Range: 0–7 points
Selection bias/confounding
(6 items)
Range: 0–6 points
Statistical power
(1 modified item)
Range: 0–1 points
Total score
(27 items)
Range: 0–28 points
Overall grading
Excellent (24–28)
Good (19–23)
Fair (14–18)
Poor (< 14)
Randomised controlled trials (RCTs)        
[35] (2011) 11 2 7 6 0 26 (92.9%) Excellent
[36] (2013) 10 3 7 5 0 25 (89.3%) Excellent
[37] (2014) 11 0 7 6 1 25 (89.3%) Excellent
[38] (2022) 11 2 6 5 1 25 (89.3%) Excellent
[39] (2019) 11 1 6 6 1 25 (89.3%) Excellent
[40] (2016) 10 2 6 6 0 24 (85.7%) Excellent
[41] (2017) 10 3 7 4 0 24 (85.7%) Excellent
[42] (2010) 10 1 6 6 0 23 (82.1%) Good
[43] (2020) 10 2 5 5 1 23 (82.1%) Good
[44] (2021) 10 2 4 6 1 23 (82.1%) Good
[45] (2017) 10 0 6 5 1 22 (78.6%) Good
[46] (2019) 9 2 6 3 0 20 (71.4%) Good
Reference (year) Quality of reporting
(10 items)
Range: 0–11 points
External validity
(3 items)
Range: 0–3 points
Internal validity
(7 items)
Range: 0–7 points
Selection bias/confounding
(4 items)
Range: 0–4 points
Statistical power (1 modified item)
Range: 0–1 points
Total score
(25 items)
Range: 0–26 points
Overall grading
Excellent (22–26)
Good (18–21)
Fair (13–17)
Poor (< 13)
Controlled clinical trials (CCT; non-randomised)a        
[47] (2017) 10 2 6 4 1 23 (88.5%) Excellent
[48] (2012) 10 1 5 3 0 19 (73.1%) Good
[49] (2018) 7 1 5 3 1 17 (65.4%) Fair
Reference (year) Quality of reporting
(10 items)
Range: 0–11 points
External validity
(3 items)
Range: 0–3 points
Internal validity
(5 items)
Range: 0–5 points
Selection bias/confounding
(2 items)
Range: 0–2 points
Statistical power (1 modified item)
Range: 0–1 points
Total score
(21 items)
Range: 0–22 points
Overall grading
Excellent (19–22)
Good (16–18)
Fair (11–15)
Poor (< 11)
Quasi-experimental (uncontrolled)b        
[50] (2015) 9 3 5 2 0 19 (86.4%) Excellent
[51] (2017) 10 1 5 2 0 18 (81.8%) Good
Reference (year)  Quality of reporting
(9 items)
Range: 0–10 points
External validity
(3 items)
Range: 0–3 points
Internal validity
(5 items)
Range: 0–5 points
Selection bias/confounding
(3 items)
Range: 0–3 points
Statistical power (1 modified item)
Range: 0–1 points
Total score
(21 items)
Range: 0–22 points
Overall grading
Excellent (19–22)
Good (16–18)
Fair (11–15)
Poor (< 11)
Observational Cohort (uncontrolled)c        
[52] (2013) 10 3 5 3 0 21 (95.5%) Excellent
[53] (2013) 10 2 5 3 0 20 (90.9%) Excellent
[54] (2011) 10 2 4 2 1 19 (86.4%) Excellent
[55] (2019) 8 2 5 3 1 19 (86.4%) Excellent
  1. The following inapplicable items were not included in the quality assessment for this study design:
  2. aSelection bias sub-scale: -Q23. Were study subjects randomised to intervention groups?; Q24. Was the randomised intervention assignment concealed from both patients and health care staff until recruitment was complete and irrevocable?
  3. bInternal validity sub-scale:—Q14. Was an attempt made to blind study subjects to the intervention they have received?; Q15. Was an attempt made to blind those measuring the main outcomes of the intervention? Selection bias sub-scale:—Q22. Were study subjects in different intervention groups (trials and cohort studies) or were the cases and controls (case–control studies) recruited over the same period of time?; Q23. Were study subjects randomised to intervention groups?; Q24: Was the randomised intervention assignment concealed from both patients and health care staff until recruitment was complete and irrevocable?; Q25. Was there adequate adjustment for confounding in the analyses from which the main findings were drawn?
  4. cReporting sub-scale: -Q8. Have all important adverse events that may be a consequence of the intervention been reported?; Internal validity sub-scale:—Q14. Was an attempt made to blind study subjects to the intervention they have received?; Q15. Was an attempt made to blind those measuring the main outcomes of the intervention?; Selection bias sub-scale:—Q22. Were study subjects in different intervention groups (trials and cohort studies) or were the cases and controls (case–control studies) recruited over the same period of time?; Q23. Were study subjects randomised to intervention groups?; Q24: Was the randomised intervention assignment concealed from both patients and health care staff until recruitment was complete and irrevocable?