Table 2:

Summary of Grading of Recommendations, Assessment, Development and Evaluation (GRADE) assessment (32)

OutcomeCohortGRADE assessment*Rating up§Overall certainty
Study designRisk of biasInconsistencyIndirectnessImprecisionPublication bias
PainAcute+4−1−1000+13
Subacute+4−1−1000+13
Persistent+4−1−10−20+11
DisabilityAcute+4−1−1000+13
Subacute+4−1−1000+13
Persistent+4−1−10−20+11
  • * Scores defined as follows: 0 = no serious concern, −1 = serious concern, −2 = very serious concern, +1 = well-defined pattern, +2 = very well-defined pattern.

  • Acute low back pain = < 6 weeks; subacute low back pain = 6 to less than 12 weeks and persistent low back pain =12 to less than 52 weeks.

  • Note that all longitudinal cohort studies initially provided high confidence and therefore started with a +4 rating.

  • § Rating up was considered if events over time followed a well-defined pattern (+1) or a very well-defined pattern (+2) that would increase confidence in the estimates.

  • Certainty scores defined as follows: 1 = very low certainty, 2 = low certainty, 3 = moderate certainty, 4 = high certainty.