Table 2.
Summary of predictors
| Studies assessing the association |
Studies reporting a significant association |
|||||||
|---|---|---|---|---|---|---|---|---|
| Category | Baseline predictor | Maximum follow-up length | Number of studies | Number of patients | Number of studies | Number of patients | % of total sample in significant studies | Level of evidence§ |
| Demographics | Age at baseline | 20 | 18 | 10.7k | 13 | 9.8k | 91.6% | ✓✓ |
| Female gender | 15 | 21 | 11.3k | 13 | 9.9k | 87.4% | ✓✓ | |
| Patient reported outcomes | HAQ | 20 | 10 | 4.0k | 9 | 4.0k | 99.0% | ✓✓ |
| Pain VAS | 15 | 6 | 2.9k | 5 | 2.8k | 93.6% | ✓✓ | |
| Disease activity | DAS28 | 6 | 5 | 1.1k | 4 | 888 | 79.2% | – |
| Swollen joint count | 20 | 5 | 2.6k | 1 | 684 | 26.6% | ✗ | |
| Tender joint count | 15 | 4 | 2.5k | 2 | 2.1k | 84.5% | ✓ | |
| Ritchie Index | 6 | 2 | 233 | 2 | 233 | 100% | – | |
| CRP | 6 | 4 | 510 | 2 | 279 | 54.7% | – | |
| ESR | 20 | 6 | 2.2k | 2 | 1.6k | 72.3% | ✓ | |
| Serology | RF | 20 | 11 | 4.6k | 3 | 546 | 11.9% | ✗✗ |
| ACPA | 20 | 6 | 3.8k | 1 | 2.0k | 52.9% | – | |
| Other | Erosions | 20 | 5 | 2.7k | 1 | 191 | 7.0% | ✗✗ |
| Genetics | 20 | 8 | 4.0k | 1 | 2.2k | 54.6% | – | |
| Morning stiffness | 20 | 3 | 424 | 3 | 424 | 100% | – | |
| BMI | 15 | 1 | 1.6k | 1 | 1.6k | 100% | – | |
| Immigrant status | 15 | 1 | 1.4k | 1 | 1.4k | 100% | – | |
| SES | 5 | 2 | 1.0k | 2 | 1.0k | 100% | – | |
| Reproductive factors | 15 | 2† | –† | 2 | –† | – | ||
| Other biomarkers | 20 | 5 | –† | 2 | –† | – | ||
†Reproductive factors/other biomarkers included are heterogeneous and therefore analysis populations were not summed.
§Key.
✓✓ = ≥ 85% total participants in studies reporting significant association & ≥2000 total participants studied;
✓ = ≥ 60% & <85% total participants in studies reporting significant association & ≥2000 total participants studied;
– = ≥40% & <60% or <2000 total participants;
✗ = ≥15% & <40% total participants in studies reporting significant association & ≥2000 total participants studied;
✗✗ = <15% total participants in studies reporting significant association & ≥2000 total participants studied.
ACPA = anti-citrullinated protein antibody, BMI = body mass index, CRP = C-reactive protein, DAS28 = Disease activity Score (28), ESR = erythrocyte sedimentation rate, HAQ = Health Assessment Questionnaire, N = number, RF = rheumatoid factor, SES = socioeconomic status, VAS = visual analogue scale.