Table 2

 Demographic and clinical characteristics of subjects with painful knee OA at baseline

CharacteristicsSubjectsp Value†
(n = 600)
Results are shown as mean (SD) unless indicated otherwise.
*K&L, Kellgren and Lawrence radiological grade ⩾3 observed in both femorotibial compartments and/or in femoropatellar compartment of the knee studied; †joint effusion was considered as a binary variable: “present” if graded moderate or important, “absent” if graded absent or minimal; only those subjects with effusion present are included here. ‡morning stiffness was also considered as a binary variable: yes, if ⩾30 minutes and no, if ⩽30 minutes; §WOMAC, Western Ontario and McMaster Universities OA Index, Fisher’s exact test for statistically significant differences between countries.
Age (years)66.7 (9.8)0.0125
Body mass index (kg/m2)29.9 (5.3)0.0001
    Male, No (%)165 (27.5)
    Female, No (%)435 (72.5)
Disease duration (years)6.0 (6.8)0.1029
K&L radiological grade ⩾3*, No (%)399 (66.5)0.0063
Knee pain intensity on VAS63 (18.5)0.0001
Joint effusion at clinical examination†, No (%)204 (34.0)0.0001
Sudden aggravation of knee pain in previous 2 weeks, No (%)107 (17.8)0.0001
Duration of morning stiffness (min):
    on VAS13.9 (17.9)0.5603
    ⩾30 minutes‡, No (%)100 (16.7)0.9571
Night awakenings due to knee pain, No (%)171 (28.5)0.0438
    Pain subscale (0–100)51.7 (20.2)0.0001
    Stiffness subscale (0–100)53.4 (25.3)0.0001
    Physical function subscale (0–100)52.0 (19.9)0.0001
Clinical knee OA severity on VAS (0-100)
    Patient’s global assessment64.2 (21.4)0.0001
    Physician’s global assessment55.8 (19.5)0.0001