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. 2015 Sep 15;75(7):1336–1342. doi: 10.1136/annrheumdis-2015-207760

Table 1.

Summary of baseline covariates and their relation to prescription of tocilizumab (TCZ) as monotherapy

  Prescription of TCZ as monotherapy
Covariate Summary (n=2057) Proportion of mono (%) OR (95% CI) for mono (n=1359)
Age (years) 55 (13.1)
56 (46–64)
1.38 (1.11 to 1.71) per 20 years more
Sex (%) (n=2056) Male 21 24 Reference
Female 79 29 1.30 (0.92 to 1.83)
Disease duration (years) (n=1900) 11.4 (9.5)
9.1 (4.1–16.1)
1.11 (0.96 to 1.27) per 10 years more
Seropositivity (%) (n=1891) No 18 27 Reference
Yes 82 28 1.08 (0.75 to 1.54)
Number of prior biologics (%)
(n=2056)
0 19 29 Reference
1 26 26 0.82 (0.54 to 1.25)
≥2 55 28 0.76 (0.51to 1.13)
Corticosteroids (%) (n=2011) No 51 33 Reference
Yes 49 22 0.74 (0.56 to 0.99)
DAS28 (n=1914) 5.0 (1.4)
5.1 (4.1–6.0)
1.14 (0.89 to 1.45) per 2 units more
HAQ (n=1673) 1.4 (0.7)
1.5 (1.0–2.0)
0.95 (0.77 to 1.19) per 1 unit more
Year of TCZ initiation (%) 2009 15 19 Reference
2010 23 22 1.23 (0.78 to 1.96)
2011 20 24 1.40 (0.87 to 2.25)
2012 22 35 2.07 (1.30 to 3.28)
2013 20 38 2.58 (1.62 to 4.10)
Country (%) Czech Republic 12.9 23 0.66 (0.39 to 1.12)
Denmark 35.5 31 0.92 (0.60 to 1.39)
Finland 2.3 11 0.36 (0.10 to 1.27)
The Netherlands 2.4 28
Norway 3.8 52
Portugal 8.4 15 0.46 (0.24 to 0.87)
Russia 4.1 11 0.30 (0.12 to 0.79)
Slovenia 9.5 21 0.28 (0.14to 0.55)
Sweden 6.4 38 1.41 (0.82 to 2.44)
Switzerland 14.7 34 Reference

Sample sizes (n) equal the number of eligible patients presented in the header of column ‘Summary’ unless indicated otherwise. The column named ‘Summary’ provides a description of covariates in terms of mean (SD) and median (IQR) for discrete or continuous covariates and percentages for categorical covariates. The column named ‘Proportion of mono’ provides the frequency of monotherapy-initiated TCZ treatment for each category of a categorical covariate. The last column presents estimated ORs and 95% Wald CIs for prescribing TCZ as monotherapy (as compared to any type of combination therapy) based on multiple logistic regression. ORs for discrete or continuous covariates are presented for a difference corresponding approximately to the IQR. For categorical covariates, ORs with respect to the chosen reference category are shown. p Values from likelihood ratio tests for categorical covariates with more than two categories were 0.41 for number of prior biologics, <0.0001 for year of TCZ initiation and <0.0001 for country. The multiple logistic regression is based on all TCs with complete covariate information. The Netherlands (patchy data) and Norway (no HAQ recorded) lack TCs with complete covariate information.

DAS, disease activity score; HAQ, Health Assessment Questionnaire; TC, treatment courses.