Table 3

Quality of the evidence and reasons for downgrading (in bold)

Prognostic factorFollow-upPopulationStudyRisk of biasImprecisionQuality
Demographic factors
Age2 yearsMixedGrøvle et al25LowOR 0.97 (0.93 to 1.00); NSLow
Age4 yearsMixedAtlas et al23LowOR 0.7 (0.6 to 0.8)Moderate
Age10 yearsMixedAtlas et al 24ModerateOR 0.42 (0.3 to 0.58); CI crosses 0.5Very low
Age3 monthsSurgicalThan et al28ModerateOR 0.92 (0.85 to 0.99)Low
Female sex2 yearsMixedGrøvle et al25LowOR 0.61 (0.31 to 1.22); NSLow
Male sex10 yearsMixedAtlas et al24ModerateOR 0.33 (0.09 to 1.0); NSVery low
Male sex3 monthsSurgicalThan et al28ModerateOR 0.22 (0.04 to 1.09); NSVery low
General health
General health2 yearsMixedGrøvle et al25LowOR 1.03 (1.01 to 1.05)Moderate
General health6 yearsMixedAtlas et al23LowOR 1.1 (1.0 to 1.2)Moderate
General health3 monthsSurgicalThan et al28ModerateOR 1.03 (0.98 to 1.08); NSVery low
Pain and disability
Low back pain intensity4 yearsMixedAtlas et al23LowOR 0.8 (0.6 to 0.9)Moderate
Low back pain frequency10 yearsMixedAtlas et al24ModerateNo data; NSVery low
Bothersomeness2 yearsMixedGrøvle et al25LowOR 0.89 (0.82 to 0.97)Moderate
Opioid use within 1 month postoperative3 yearsSurgicalO’Donnell et al27LowOR 0.44 (0.26 to 0.75); CI crosses 0.5Low
Physical function10 yearsMixedAtlas et al24ModerateOR 1.4 (1.1 to 1.8)Low
Physical function3 monthsSurgicalThan et al28ModerateOR 1.06 (0.997 to 1.13); NSVery low
Pain/disability presurgery2 yearsSurgicalSchade et al22ModerateNo CI presented; NS; <10 participants/PFVery low
Psychological factors
Fear avoidance2 yearsMixedGrovle et al25LowOR 0.93 (0.90 to 0.97)Moderate
Fear avoidance*6 monthsSurgicalden Boer et al26LowOR 1.09 (1.01 to 1.17)Moderate
Mental health10 yearsMixedAtlas et al24ModerateNo data; NSVery low
Depression*2 yearsSurgicalSchade et al22Moderate<10 participants/PFVery low
Psychiatric comorbidity3 yearsSurgicalO’Donnell et al27LowOR 0.19 (0.05 to 0.68); CI crosses 0.5Low
Occupational mental stress*2 yearsSurgicalSchade et al22Moderate<10 participants/PFVery low
Passive pain coping*6 monthsSurgicalden Boer et al26LowOR 1.08 (1.0 to 1.16)Moderate
Other health-related factors
Smoking status3 monthsSurgicalThan et al28ModerateOR 4.37 (0.82 to 23.27), NSVery low
Clinical examination
Positive SLR-test2 yearsMixedGrøvle et al25LowOR 0.44 (0.20 to 0.95)Moderate
Quebec classification10 yearsMixedAtlas et al24ModerateNo data; NSVery low
Care related factors
Physician expected benefit of surgery10 yearsMixedAtlas et al24ModerateOR 5.0 (1.65 to 17.7); CI crosses 2.0Very low
Initial treatment: surgery10 yearsMixedAtlas et al24ModerateOR 1.4 (0.46 to 4.6); NSVery low
Revision surgery with fusion3 yearsSurgicalO’Donnell et al27LowOR 0.56 (0.33 to 0.97)Moderate
Work-related factors
Receiving workers’ compensation4 yearsMixedAtlas et al23LowOR 0.6 (0.3 to 1.2); NSLow
Physical work load*6 monthsSurgicalden Boer et al26LowOR 1.19 (1.07 to 1.31)Moderate
Job satisfaction6 monthsSurgicalden Boer et al26LowNo CI presented; NSLow
Duration sick leave6 monthsSurgicalden Boer et al26LowNo CI presented; NSLow
  • *Prognostic factor for reduced return to work; CI, 95% CI; NS, non-significant; PF, prognostic factor.