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Table 2 The GRADE evidence quality for primary outcome, sensitivity analysis, and secondary outcomes

From: Subglottic secretion suction for preventing ventilator-associated pneumonia: an updated meta-analysis and trial sequential analysis

Categaries Outcomes Number of studies Risk ratio or mean difference (95 % CI) P P for heterogeneity I2 (%) Quality
Primary outcome Sensitivity analysis VAP high-quality trials 4 [17, 20, 34, 42] 0.54 (0.40, 0.74) <0.00001 0.39 0 Moderatec
VAP total trials 20 [17, 2024, 3043] 0.55 (0.48, 0.63) <0.00001 0.85 0 Higha
  VAP invasive diagnosis 13 [17, 20, 22, 30, 31, 33, 3540, 42] 0.55 (0.47, 0.65) <0.00001 0.60 0 Higha
  VAP excluding trials with multiple manipulations 16 [17, 2224, 3034, 3643] 0.55 (0.48, 0.65) <0.00001 0.97 0 Higha
  VAP randomization 12 [17, 2022, 34, 35, 3742] 0.56 (0.47, 0.66) <0.00001 0.37 7 Higha
VAP allocation concealment 5 [17, 20, 34, 39, 42] 0.56 (0.42, 0.74) <0.00001 0.53 0 Moderatec
VAP assessment blinded 8 [17, 20, 23, 31, 34, 35, 38, 42] 0.53(0.42, 0.66) <0.00001 0.34 11 Moderatec
VAP participants more than 100 10 [17, 21, 22, 3032, 34, 38, 39, 42] 0.54(0.45, 0.65) <0.00001 0.55 0 Higha
VAP intermittent SSS 9 [2123, 30, 34, 37, 38, 42, 43] 0.52 (0.43, 0.64) <0.00001 0.25 22 Higha
VAP continuous SSS 11 [20, 22, 24, 3133, 35, 36, 3941] 0.61(0.5, 0.73) <0.00001 0.91 0 Higha
Secondary outcomes Early-onset VAP 9 [2224, 33, 3638, 42, 43] 0.34 (0.25, 0.47) <0.00001 0.84 0 Moderatec
Late-onset VAP 5 [22, 33, 36, 38, 42] 0.80 (0.62, 1.02) 0.07 0.17 35 Moderatec
Gram-negative bacteria 6 [31, 32, 3840, 42] 0.58(0.43, 0.77) 0.0002 0.69 0 Moderatec
Gram-positive bacteria 5 [31, 33, 38, 40, 42] 0.32 (0.17, 0.61) 0.006 0.61 0 Lowb
ICU mortality 8 [17, 20, 30, 31, 38, 39, 41, 42] 0.98(0.85, 1.13) 0.77 0.88 0 High
Hospital mortality 7 [17, 21, 32, 34, 37, 40, 42] 0.92 (0.80, 1.05) 0.20 0.82 0 High
Time-to-onset of VAPg 7 [3033, 37, 40, 41] 3.92 (2.56, 5.27) <0.00001 <0.00001 92 Moderated
Duration of MVg 6 [20, 32, 34, 37, 38, 41] −1.17 (–2.28, –0.06) 0.006 0.06 54 Moderated
ICU length of stayg 4 [32, 34, 38, 41] 37 −1.64 (–3.95, 0.66) 0.16 0.001 81 Moderated
Hospital length of stay 3 [32, 34] −1.44 (–3.93, 1.04) 0.25 0.99 0 High
Reintubation 4 [20, 32, 39, 42] 0.77 (0.45, 1.32) 0.34 0.19 38 Lowb
  Tracheotomyg 3 [32, 38, 42] 1.14 (0.75, 1.72) 0.55 0.79 54 Lowb
  1. CI confidence interval, GRADE Grading of Recommendations Assessment, Development, and Evaluation, ICU intensive care unit, MV mechanical ventilation, NA not available, SSS subglottic secretion suctioning, VAP ventilator-associated pneumonia
  2. aTotal number of events is more than 300
  3. bTotal number of events is less than 100
  4. cTotal number of events is less than 300
  5. dI2 > 50 %
  6. eThe total number of patients is relatively small (<500)
  7. fThe total number of patients is very small (100)
  8. gRandom-effect model
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