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Table 1 Quality assessment and scores of included studies using Downs and Black quality checklist

From: A systematic review of enteric dysbiosis in chronic fatigue syndrome/myalgic encephalomyelitis

  Reference
Armstrong et al. (2016) Frémont et al. (2016) Giloteaux et al. (2016) Mandarono et al. (2015) Rao et al. (2014) Sheedy et al. (2010) Shukla et al. (2009)
1 Objective of the study clearly described 1 1 1 1 1 1 1
2 Outcomes of interest clearly stated 1 1 1 1 1 1 1
3 Patient characteristics clearly described 1 1 1 1 1 1 1
4 Interventions of interest clearly described 1
5 Are the distributions of principle confounders in each group of subjects to be compared clearly described? 0 0 0 0 0 0 0
6 Main findings of the study clearly described 1 1 1 1 1 1 1
7 Does the study provide estimates of random variability in the data 1 1 1 1 1 1 1
8 Have all important adverse events that may be a consequence of the intervention been reported? 1
9 Have the characteristics of patients lost to follow-up been described? 1
10 Have actual probability values been reported for the main outcomes 1 1 1 1 1 1 1
11 Were the subjects asked to participate in the study representative of the entire population from which they were recruited 1 1 0 0 0 1 1
12 Were those subjects who participated representative of the entire population from which they were recruited 1 1 0 0 0 1 1
13 Were the staff, places and facilities where the patients were treated representative of the treatment the majority of patients receive 0  
14 Was an attempt made to blind study subjects to the intervention they received? 1
15 Was an attempt made to blind those measuring the main outcomes of the intervention 0
16 If any of the results were based on “data dredging”, was this made clear? 0 0 0 0 0 0 0
17 Do the analyses adjust for different lengths of follow-up of patients 1
18 Were the statistical tests used to assess the main outcomes appropriate? 1 1 1 1 1 1 1
19 Was compliance with the intervention reliable? 1
20 Were the main outcome measures used accurate (valid and reliable)? 1 1 1 1 1 1 1
21 Were the patients recruited from the same population? 1 1 0 0 1 1 1
22 Were subjects recruited over the same period of time? 0 0 0 0 0 1 1
23 Were study subjects randomised to intervention groups? 1
24 Was the randomised intervention assignment concealed from both patients and healthcare staff until recruitment was complete and irrevocable? 0
25 Was there adequate adjustment for confounding in the analyses from which the main findings were drawn? 0
26 Were the losses of patient to follow-up taken into account? 1
27 Did the study have sufficient power to detect a clinically important effect where the probability value for a difference being due to chance is less than 5%? 0 0 0 0 0 0 0
Score 73% 67% 47% 47% 56% 80% 80%