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Table 2 Criteria and benchmarks to assess certainty of the evidence using GRADE [10, 12, 16]

From: Functional electrical stimulation cycling exercise after spinal cord injury: a systematic review of health and fitness-related outcomes

GRADE criterion Meaning Benchmark used in this review
Risk of bias Quality of the evidence No risk of bias if at least one Level 1 study was present
Serious risk of bias if only one Level 2 was present
Very serious risk of bias if no Level 1 or 2 studies were present
Inconsistency Results for a given outcome not similar across studies No inconsistency if improvements shown in at least:
– Two thirds of Level 1 or 2 studies and half of Level 3 or 4 studies; or
– Half of Level 1 or 2 studies and two third of Level 3 or 4 studies; or
– Two thirds of Level 3 or 4 studies in absence of Level 1 or 2 studies
Imprecision Insufficient statistical power or wide confidence intervals No imprecision if at least one study was sufficiently powered and at least one study showed narrow confidence intervals surrounding the estimate of effects
Indirectness Evidence differs from study eligibility criteria (PICO) No indirectness if—across the studies—the following participant characteristics were represented: male/female, young and middle-aged adults (16–65 years) and older adults (> 65 years), time since injury > 1 year and > 1 year, and lesion characteristics (AIS and lesion level) with sufficient lower motor neuron capacity to respond to FES cycling
Publication bias Selective publication of studies Publication bias present if unpublished studies added to the evidence summary would have changed assessment of any of the criteria shown above
Reasons for upgrading level of certainty in the evidence If lower-quality studies provide convincing evidence Consistent effects across a large number of Level 2, 3 or 4 studies
Plausible bias caused by including participants not responsive to FES cycling
Dose–response gradient present in one study or across all studies
  1. GRADE certainty in the evidence can be ‘High’, ‘Moderate’, ‘Low’ or ‘Very Low’, subject to the presence of the criteria presented in this table [10, 12]
  2. AIS American Spinal Injury Association Impairment Scale, PICO Participants, Intervention, Comparator, Outcomes