Table 1 Components of the effectiveness algorithm, assessed between the index date and the outcome visit date approximately one year later

High adherence to index drug (required)

For etanercept, adalimumab and oral medications, must be ≥ 80% adherent to therapy, calculated as a medication possession ratio [38]

For infliximab, must have received at least the number of infusions expected between the index and outcome visit dates to conform to a schedule of 0, 2, 6 and 14 weeks and every 8 weeks thereafter

For abatacept, must have received the number of infusions expected between the index and outcome visit dates to conform to a schedule of once-monthly dosing; missing one infusion is permissible

For rituximab, criterion is not applicable

Biologic switch or add (prohibited)

Between the index and outcome visit dates, patient cannot initiate therapy with a new biologic agent

Addition of a new nonbiologic DMARD (prohibited)

Between the index and outcome visit dates, patient cannot initiate therapy with a new nonbiologic DMARD (methotrexate, sulfasalazine, leflunomide or hydroxychloroquine) that they were not already taking during the 6 months prior to the index date

Increase in biologic dose or frequency (prohibited)

For etanercept and adalimumab, dose escalation of etanercept to 50 mg twice weekly or adalimumab 40 mg once weekly is prohibited

For infliximab, difference between ending and starting dose, with each dose rounded up to the nearest 100 mg cannot be ≥ 100 mg. The number of infusions must be within 120% of the number expected assuming a 0-, 2-, or 6-week load and an 8-week infusion schedule

For abatacept, difference between ending and starting dose cannot be ≥ 100 mg

For rituximab, criterion is not applicable

More than one glucocorticoid joint injection (prohibited)

Cannot receive glucocorticoid injections† on more than one unique calendar day between the index date + 90 days and the outcome visit date, inclusive

Increase in dose of oral glucocorticoid (prohibited)

For patients who received no prescriptions for oral glucocorticoids during the 6 months prior to the index date, cannot have received more than 30 days of oral glucocorticoids between the index date + 90 days and the outcome visit date, inclusive

For patients who received prescriptions for oral glucocorticoids in the 6 months prior to the index date, the cumulative glucocorticoid dose in the 6 months prior to the outcome visit date must be similar (that is, within 120%) to the cumulative dose in the 6 months prior to the index visit date