Opioid users show worse baseline knee osteoarthritis and faster progression of degenerative changes: a retrospective case-control study based on data from the Osteoarthritis Initiative (OAI)

Table 3 Differences in score progression over 4 years between opioid users^a and controls^b

	Longitudinal analysis			Sensitivity analysis, KOOS pain^e
Score	Coef.^c	95% CI	P^d	Coef.^c	95% CI	P^d
WORMS^f
Total	4.7	2.9, 6.5	< 0.001	4.7	2.8, 6.7	< 0.001
Cartilage	1.5	0.6, 2.3	0.001	1.4	0.5, 2.3	0.002
Meniscus	1.7	1.1, 2.3	< 0.001	1.7	1.0, 2.3	< 0.001
BMEL	−0.1	−0.6, 0.3	0.53	0.1	−0.4, 0.5	0.83
Subchondral cyst	0.5	0.1, 0.9	0.02	0.5	0.0, 0.9	0.03
KOOS^g
QOL	−3.8	−8.3, 0.7	0.10	−6.9	−11.6, −2.1	0.005
Symptom	1.3	−2.1, 4.7	0.45	−0.7	−4.4, 3.0	0.72
Pain	0.6	−3.3, 4.5	0.75	Omitted^h

^an = 79. ^bn = 158. ^cCoefficients indicate differences in scores between opioid users and controls. ^dSignificant P values are printed bold. ^eResults of the sensitivity analysis, adjusted for baseline KOOS pain. ^fA higher WORMS score indicates worse structural knee damage. ^gKOOS scores range from 0 to 100, with lower KOOS scores reflecting worse reported knee problems. ^hKOOS pain was omitted as outcome from the longitudinal analysis. WORMS, Whole-Organ Magnetic Resonance Imaging score; KOOS, Knee injury and Osteoarthritis Outcome Score; BMEL, bone marrow edema-like lesions; QOL, quality of life; Coef., coefficient; 95% CI, 95% confidence interval. All analyses are adjusted for age, sex, body mass index, race, and baseline Kellgren-Lawrence grade

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