Table 2.

Multivariate regression analysis for hip OA at 2-years and/or 5-year follow up according to the ACR classification criteria (n = 198, 80 cases, a priori risk = 0.40)

Baseline characteristics	Analysis per category OR (95% CI)	Multivariate analysis OR(95% CI)	PPV	NPV	LR+	LR-
Demographics
Age (<= 50vs. > 50 years)	0.53(0.28–1.01)	0.90(0.41–1.99)	0.36	0.48	0.84	1.6
Complaints and symptoms
Pain last week, NRS	1.15(0.99–1.33)	1.04(0.87–1.26)	na	na	na	na
Morning stiffness hip (yes = 1/no = 0)	2.60 (1.14–3.71)	2.39 (1.14–4.98)	0.51	0.66	1.56	0.75
Comorbidities and interventions
Knee pain (yes = 1/no = 0)	0.63 (0.33–1.20)	0.71 (0.32–1.55)	0.37	0.51	0.89	1.42
Painkillers (yes = 1/no = 0)	2.01 (1.12–3.59)	1.60 (0.75–3.41)	0.5	0.67	1.47	0.73
Physical examination
Painful hip internal rotation (yes = 1/no = 0)	2.59 (1.43–4.67)	2.53 (1.23–5.19)	0.53	0.69	1.71	0.66
Hip flexion ROM (0 = > 115° vs. 1 = <= 115°)	2.00 (1.12–3.67)	2.33 (1.17–4.64)	0.5	0.67	1.47	0.73
Diagnostic tests
ESR < 20 mm/h	3.54 (1.30–7.13)	2.94 (1.13–7.61)	0.46	0.77	1.22	0.4

Bold values indicate significant values (p < 0.05) in the final model

ACR American College of Rheumatology, OR odds ratio, PPV positive predictive value, NPV negative predictive value, NRS numeric rating scale, ROM range of motion, LR+ positive likelihood ratio, LR- negative likelihood ratio, na not applicable (continuous variable), ESR erythrocyte sedimentation rate