To meet their clinical goals, it is crucial for rheumatoid arthritis (RA) patients to be adherent to their treatments over the long term. Improving treatment adherence remains a major unmet need in the RA disease space.

A recent study by Stolshek and colleagues (2018), published in the American Journal of Managed Care as part of a special Pharmacy Benefits issue, assessed the extended adherence of RA patients to treatment with a single biological DMARD (bDMARD) over a two-year time period. Overall, the study confirmed that the level of adherence among RA patients to bDMARD treatment was unsatisfactory.

However, it offered some insight into the types of patients who were most likely to remain adherent long-term. Specifically, this included patients who were persistent and adherent in the first year of treatment. It also included patients who were of older age, male sex, and had prior experience with DMARDs. GlobalData believes that these findings can serve as a useful starting point for industry and academia in the development of outreach efforts to help improve long-term adherence to bDMARD therapy.

The study analysed administrative claims data from a total of 10,374 bMARD-naïve patients with RA. Patients were assigned to a treatment cohort based on their initial or “index” bDMARD claims and remained in the assigned treatment group despite any future changes to their treatment regimen. Of the six bDMARDs explored in the study, abatacept, adalimumab, certolizumab pegol, etanercept, golimumab, and infliximab, the two most widely used were adalimumab (42.7%) and etanercept (37.8%).

Overall, less than half (46.0%) of all patients analyzed were adherent to index bDMARD treatment in the first year and about a third (33.6%) in the second year. Of these patients, only 29.7% (N = 3,076) were deemed as having been “effectively treated” in the first year. Effectively treated patients had shown high adherence (proportion of days covered ≥80%), had not increased the index bDMARD dose or dosing frequency, had not switched to a different bDMARD, had not received more than one glucocorticoid (GC) injection during the year, and had not increased oral GC dose.

In year two, 6,251 patients remained on the same index therapy as began in year one and thus were eligible for inclusion in adherence analyses in the second year of treatment. Of these patients, 44.4% were adherent in year two. This included 59.0% of the 2,934 patients deemed effectively treated in the first year and 31.5% of the 3,317 patients considered non-effectively treated. Among the non-effectively treated patients, 1,354 failed the adherence criterion alone, of which only 12% were found to be adherent in their second year. This suggests that adherence to therapy in the first year is an important factor in establishing adherence in year two.

Another factor evaluated for effect on second-year adherence was treatment persistence. Patients were considered persistent if they continued their index medication with no gaps for 90 days or more, for six months after beginning the index therapy. Patients persistent with their therapeutic treatment in the first six months showed greater adherence in their second year of treatment compared to those who were not (60.6% vs. 10.6%). These findings indicate that both adherence and persistence in the first year of bDMARD treatment are key factors in determining long-term adherence.

Who were the most adherent patients? Statistical predictors of high adherence in the first year and over the 24-month study period included older age, male sex, as well as prior experience with DMARDs. Additionally, when compared to etanercept, 24-month adherences were higher in patients receiving infliximab and lower in patients receiving golimumab. These statistical predictors suggest that younger, more inexperienced patients may need additional interventions and follow-up to better ensure long-term adherence. Additionally, certain drugs might promote better adherence in patients.

Taken together, findings from this study suggest that long-term adherence to bDMARD therapy remains an important unmet need in the RA space that requires industry and academic attention. It highlights the importance of promoting patient adherence and persistence to therapy within the first year and identifies certain patient groups that may need additional interventions and follow-up.

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