Table 3.

Missingness conditions for the simulation, 1 being the reference condition

Condition	Attrition for OMA (%)	Attrition for TNFi (%)	CDAI12 OR for OMA	CDAI12 OR for TNFi	Missingness for CC, LOCF, LUNDEX, NRI, IPW1	Missingness for IPW2 and CARRAC
1	20	20	1	1	MNAR	MAR
2	10	20	1	1	MNAR	MAR
3	15	20	1	1	MNAR	MAR
4	25	20	1	1	MNAR	MAR
5	30	20	1	1	MNAR	MAR
6	10	10	1	1	MNAR	MAR
7	15	15	1	1	MNAR	MAR
8	25	25	1	1	MNAR	MAR
9	30	25	1	1	MNAR	MAR
10	20	20	1.07	1	MNAR	MNAR for OMA, MAR for TNFi
11	20	20	1.14	1	MNAR	MNAR for OMA, MAR for TNFi
12	20	20	1.07	1.07	MNAR	MNAR
13	20	20	1.14	1.14	MNAR	MNAR

Attrition for OMA of TNFi indicates the percentage of missing CDAI at 12 months for the other mode of action treatment (OMA) of the reference treatment TNFi, CDAI₁₂ OR are the OR of the CDAI value at 12 months (CDAI₁₂) in the generalised linear model predicting missingness of CDAI₁₂ used to create missing values in the simulation. A CDAI12 OR of 1.07 or 1.14 implies that the odds of having a CDAI12 missing is multiplied by 2 or by 4 for an increase of 10 points of CDAI12. The column ‘Missingness for CC, LOCF, LUNDEX, NRI, IPW1’ indicates if the missing data are MNAR or MAR for the methods CC, LOCF, LUNDEX, NRI, IPW not accounting for the reasons for treatment cessation in the attrition weights (IPW1). The column ‘Missingness for IPW2 and CARRAC’ does the same for IPW accounting for the reasons for treatment cessation in the attrition weights (IPW2) and CARRAC.

CARRAC, confounder-adjusted response rate with attrition correction; CC, complete case analysis; CDAI, Clinical Disease Activity Index; IPW, inverse probability weighting; LDA, low disease activity; LOCF, last observation carried forward; MAR, missing at random; MNAR, missing not at random; NRI, non-responder imputation; OMA, another mode of action; TNF, tumor necrosis factor.