Table 1

Baseline characteristics by disease onset group compared using ANOVA

VariableAll patientsConcordant MD vs patient-reported RA symptom onset date (<30 days)Discordant MD vs patient-reported symptom onset date (>30 days)P value
Patient onset precedes MD datePatient onset after MD date
N26831940497246
Symptom duration by MD (days), median (IQR)166 (138)161 (133)163 (140)213 (144)<0.001
Symptom duration by patient (days), median (IQR)178 (163)160 (135)373 (430)132 (126)<0.001
Age, years, mean (SD)54 (15)55 (15)52 (16)54 (16)0.003
Female (%)1911 (71)1375 (71)356 (72)180 (73)0.738
Caucasian (%)2179 (81)1598 (82)391 (79)190 (77)0.042
Education >high school (%)1454 (56)1045 (56)277 (58.1)134 (57)0.725
Income >US$50 000 (%)805 (45)559 (45)168 (43)174 (45)0.755
Smoking (%)
 Never1177 (44)834 (43)230 (46)113 (46)0.370
 Past smoker1030 (38)755 (39)182 (37)93 (38)0.594
 Current smoker465 (17)341 (18)84 (17)40 (16)0.822
# of comorbidities2 (2)2 (2)2 (2)2 (2)0.715
 Fibromyalgia (%)57 (2)35 (2)17 (3)5 (2)0.085
 Osteoarthritis (%)314 (12)225 (12)61 (12)28 (11)0.909
2010 ACR criteria (%)2052 (76)1488 (77)354 (73)200 (81)0.047
RF positive (%)1402 (59)994 (57)259 (62)149 (69)0.001
ACPA positive (%)1005 (53)739 (52)166 (52)100 (60)0.162
ACPA titre87 (139)82 (135)101 (136)110 (167)0.009
Erosions (%)522 (20)376 (19)95 (19)51 (21)0.851
DAS284.9 (1.5)4.9 (1.5)4.7 (1.4)4.9 (1.4)0.015
Swollen joint count (0–28)7 (6)7 (6)6 (6)7 (6)0.010
Tender joint count (0–28)8 (7)8 (7)8 (7)8 (6)0.204
HAQ-DI (0–3)1 (1)1 (1)1 (1)1 (1)0.085
ESR27 (22)27 (23)24 (20)27 (22)0.006
CRP14 (18)14 (19)12 (16)16 (20)0.024
MD global score (0–10)4.6 (2.5)4.6 (2.5)4.7 (2.5)5.1 (2.5)0.003
Patient global score (0–10)5.7 (3.0)5.7 (2.9)5.6 (3.0)5.9 (2.9)0.398
CDAI25 (14)26 (14)24 (14)26 (14)0.153
SDAI27 (15)27 (15)26 (15)27 (14)0.202
Baseline oral steroid (%)777 (29)606 (31)112 (22)59 (24)<0.001
Baseline parenteral steroid (%)740 (28)542 (28)132 (27)66 (27)0.797
Oral steroid at 3 months (%)633 (24)479 (25)102 (21)52 (21)0.095
Parenteral steroid at 3 months321 (12)220 (11)61 (12)40 (16)0.079
 Initial RA treatment (%)
 MTX monotherapy725 (27)1517 (27)144 (29)64 (26)0.543
 MTX combination1062 (40)798 (41)162 (33)102 (42)0.002
 Other DMARDs494 (18)355 (18)99 (20)40 (16)0.466
 Biologic49 (2)37 (2)10 (2)2 (1)0.455
 None of the above353 (13)233 (12)82 (16)38 (15)0.016
RA treatment at 3 months (%)
 MTX monotherapy608 (23)432 (22)128 (26)48 (20)0.113
 MTX combination1201 (45)901 (46)185 (37)115 (47)0.001
 Other DMARDs433 (16)305 (16)90 (18)38 (15)0.415
 Biologic104 (4)77 (4)19 (4)8 (3)0.858
 None of the above337 (13)225 (12)75 (15)37 (15)0.052
  • Results are in mean (SD) if not specified otherwise.

  • Statistically significant values are indicated in bold.

  • ACPA, anticitrullinated protein antibodies; ACR, American College of Rheumatology; ANOVA, analysis of variance; CDAI, Clinical Disease Activity Index; CRP, C reactive protein; DAS28, Disease Activity Score based on 28 joint count; DMARD, disease-modifying antirheumatic drug; ESR, erythrocyte sedimentation rate; HAQ-DI, Health Assessment Questionnaire-Disability Index; MD, medical doctor; MTX, methotrexate; RF, rheumatoid factor; SDAI, Simplified Disease Activity Index.