Table 2.

Between‐phenotype differences for the isolated first MTP joint OA and polyarticular foot OA phenotype at 18 months using the no or minimal foot OA phenotype as the reference category^a

	Isolated first MTP joint OA			Polyarticular foot OA
	βadj b	ORadj b	95% CI	βadj b	ORadj b	95% CI
Foot pain severity in previous month (NRS)c	0.29		−0.27, 0.85	0.46		−0.21, 1.13
Rasch‐transformed MFPDI pain scored	0.02		−0.28, 0.33	0.37		−0.01, 0.74
Rasch‐transformed MFPDI function scored	0.00		−0.31, 0.31	0.27		−0.11, 0.65
SF‐12 PCS scored	−1.04		−2.96, 0.88	0.69		−3.11, 1.73
SF‐12 MCS scored	−0.49		−2.57, 1.59	−0.69		−3.32, 1.94
HADS anxiety scored	−0.08		−0.76, 0.60	−0.16		−0.96, 0.65
HADS depression scored	−0.06		−0.60, 0.49	0.20		−0.46, 0.86
Frequent foot pain in the previous monthe		0.94	0.57, 1.56		1.43	0.79, 2.59
Dissatisfaction with foot symptomsf		0.64	0.38, 1.09		1.00	0.55, 1.82
Bilateral hallux valgusg		1.45	0.75, 2.81		1.26	0.58, 2.72
Unilateral hallux valgus, left footg		2.96h	1.23, 7.12h		2.18	0.76, 6.30
Unilateral hallux valgus, right footg		0.67	0.30, 1.52		0.77	0.31, 1.95
Hip pain in the previous year		0.84	0.48, 1.49		0.94	0.46, 1.93
Knee pain in the previous year		0.82	0.43, 1.60		1.55	0.67, 3.59

^aMTP = metatarsophalangeal; OA = osteoarthritis; adj = adjusted; OR = odds ratio; 95% CI = 95% confidence interval; NRS = numeric rating scale; MFPDI = Manchester Foot Pain and Disability Index; SF‐12 = Short Form 12; PCS = physical component summary; MCS = mental component summary; HADS = Hospital Anxiety and Depression Scale.

^bAdjusted for baseline scores, age, sex, and body mass index.

^c0 = no pain and 10 = worst possible pain.

^dHigher MFPDI indicate more pain/functioning; higher SF‐12 PCS and MCS scores indicate better health; and higher HADS scores indicate worse psychiatric ratings.

^eDefined as frequent pain, aching, or stiffness on all or most days in the previous month.

^fDefined as participants being very or somewhat dissatisfied with the foot symptoms persisting for the rest of their lives.

^gHallux valgus was defined according to Roddy et al's 13 self‐report instrument and dichotomized definition.

^hStatistically significant (P < 0.05).