Baseline demographics, disease activity and reasons for terminating TNFi treatment according to smoking status at the baseline visit
| Smoking status | Smoking status unknown | |||||
|---|---|---|---|---|---|---|
| Current | Never | Previous | p Value* | p Value† | ||
| Number, n (%) | 380 (33) | 466 (41) | 302 (26) | 240 (17) | ||
| Age, years | 47 (38–55) | 47 (37–56) | 52 (44–57) | 0.9 | <0.01 | 47 (37–55)¤ |
| Disease duration, years | 3 (1–8) | 5 (2–10) | 4 (1–10) | <0.01 | <0.01 | 6 (2–11)¤ |
| Women, n (%) | 197 (48) | 204 (44) | 156 (48) | 0.02 | 0.06 | 122 (51) |
| Body Mass Index, kg/m2 | 27 (23–30) | 28 (24–31) | 28 (25–32) | 0.01 | 0.01 | 26 (23–31)¤ |
| TNFi drug type, n (%) | ||||||
| Adalimumab | 182 (48) | 208 (44) | 152 (50) | 0.1 | 0.01 | 92 (38) |
| Etanercept | 71 (19) | 115 (25) | 74 (25) | 62 (26) | ||
| Infliximab | 127 (33) | 143 (31) | 76 (25) | 86 (36) | ||
| TNFi start year, n (%) | ||||||
| 2000–2003 | 18 (5) | 22 (5) | 9 (3) | 0.4 | 0.1 | 26 (10)¤ |
| 2004–2007 | 112 (29) | 165 (35) | 99 (34) | 134 (55) | ||
| 2008–2011 | 250 (66) | 279 (60) | 194 (64) | 80 (33) | ||
| Methotrexate use, n (%) | 205 (54) | 247 (53) | 155 (52) | 0.8 | 0.5 | 139 (58) |
| CRP, mg/L | 8 (3–18) | 9 (3–21) | 8 (4–17) | 0.2 | 0.4 | 12 (4–29)¤ |
| Tender joint count (0–28) | 6 (2–13) | 6 (2–10) | 6 (2–13) | 0.4 | 0.5 | 8 (3–14) |
| Swollen joint count (0–28) | 2 (0–5) | 3 (1–6) | 2 (0–5) | 0.1 | 0.1 | 4 (1–8)¤ |
| HAQ | 1.1 (0.7–1.5) | 1.0 (0.5–1.5) | 0.9 (0.5–1.5) | 0.03 | 0.07 | 0.9 (0.5–1.4) |
| DAS28 | 4.6 (3.7–5.4) | 4.5 (3.6–5.3) | 4.6 (3.6–5.3) | 0.5 | 0.8 | 4.9 (3.9–5.6) |
| Patient's global (0–100), mm | 72 (54–87) | 68 (50–80) | 66 (48–82) | 0.01 | 0.01 | 65 (45–80)¤ |
| Pain (0–100), mm | 65 (45–80) | 63 (42–75) | 62 (38–75) | 0.08 | 0.08 | 60 (40–73) |
| Fatigue (0–100), mm | 72 (51–86) | 63 (40–77) | 63 (46–78) | <0.01 | 0.01 | 62 (38–76)¤ |
| Doctor's global (0–100), mm | 35 (22–55) | 30 (20–50) | 37 (25–52) | 0.8 | 0.09 | 33 (22–50) |
| Stop reason, n (%)‡ | ||||||
| Lack of efficacy | 112 (47) | 112 (47) | 88 (53) | 0.7 | 0.8 | 74 (48) |
| Adverse events | 87 (37) | 85 (36) | 55 (33) | 46 (30) | ||
| Other | 30 (13) | 36 (15) | 18 (11) | 23 (15) | ||
| Unknown | 8 (3) | 4 (2) | 4 (3) | 10 (7) | ||
Numbers are medians (IQRs) unless otherwise stated.
*Test of difference between current and never smokers (Mann–Whitney, χ2).
†Test of difference between current, previous and never smokers (Kruskal†Test of difference between current, previous and never smokers (Kruskal–Wallis).
‡Percentages of patients according to smoking status who have terminated treatment.
¤Significantly different (p <0.05) compared to patients with known smoking status.
TNFi, tumour necrosis factor alpha inhibitor; CRP,CRP, C reactive protein; DAS28DAS28, Disease Activity Score (28 joints, based on CRP); HAQHAQ, Health Assessment Questionnaire; VASVAS, Visual Analogue Scale.