Mediation effects for outcome WOMAC pain over 24 months: association of change in cartilage thickness loss over 24 months, with change in WOMAC knee
| Exposure: cartilage thickness loss over 24 months | Mediator: synovitis score change over 24 months Mean change in WOMAC knee pain over 24 months* | Mediator: BML score change over 24 months Mean change in WOMAC knee pain over 24 months* |
| Exposure: 0.1 mm cartilage thickness loss over 24 months | ||
| Controlled direct effect | 0.28 (−1.68 to 2.24)† | 0.33 (−1.62 to 2.30)† |
| Indirect effect | 0.05 (−1.91 to 2.01) | 0.01 (−1.95 to 1.97) |
| Total effect | 0.33 (−1.63 to 2.29) | 0.34 (−1.62 to 2.30) |
| Proportion mediated | 14.11% (2.07% to 26.15%) | 2.77% (−1.71% to 7.25%) |
| Exposure: 0.05 mm cartilage thickness loss over 24 months | ||
| Controlled direct effect | 0.14 (−1.82 to 2.10) | 0.17 (−1.79 to 2.13) |
| Indirect effect | 0.02 (−1.92 to 1.98) | 0.004 (−1.96 to 1.96) |
| Total effect | 0.16 (−1.80 to 2.12) | 0.17 (−1.79 to 2.13) |
| Proportion mediated | 14.11% (2.07% to 26.15%) | 2.77% (−1.71% to 7.25%) |
Positive(+) coefficient indicates an increase in the outcome WOMAC pain.
Models for mediation by change in synovitis score adjusted for standard covariates above +baseline BML score.
Models for mediation by change in BML score adjusted for standard covariates above +baseline synovitis score.
*All models adjusted for age, sex, BMI, race, depressive symptoms (CESD) and baseline WOMAC pain.
†Values are unstandardised regression coefficients representing mean change in WOMAC knee pain over 24 months.
BMI, body mass index; BML, bone marrow lesion; CESD, Center for Epidemiologic Studies Depression Scale; WOMAC, Western Ontario and McMaster Universities Osteoarthritis Index.