5 Factors that Predict Medication Nonadherence in Patients Taking Biologics for Rheumatic Disease

Analysis of questionnaire data has identified 5 factors that help predict which patients with chronic inflammatory rheumatic diseases such as psoriatic arthritis will abandon biologic treatment.

Investigators emailed the questionnaire to members of different patient associations and received 581 completed copies between June 16 and July 4, 2012. Patients answered questions about their demography, socio-economic status, and medical and therapeutic history. The medical questions focused in particular on their previous history with biologics, how they had administered biologic medications and what they believed in general about the efficacy and side effects of such medications.

Some 351 of the responders (60.4%) had ankylosing spondylitis, while 196 (33.7%) had rheumatoid arthritis, 30 (5.2%) had psoriatic arthritis and 4 (0.7%) had some other chronic inflammatory rheumatoid disease.

A total of 86 patients (14.8%) had decided to discontinue a prescribed biologic treatment at some point before the survey, and multivariate analysis comparing patients who had and had not discontinued biologic treatment revealed that certain patients were significantly more prone to self-discontinuation than others.

“Five predictive factors of this self-discontinuation were identified, which should be assessed in routine with patients with chronic inflammatory rheumatoid disease receiving biologic treatment: pain, treatment history, self-administration of injections, negative beliefs about treatment, and a lack of perceived medical and social support,” the investigators wrote in The Journal of Rheumatology.

The information from the new study supplements findings from research that has focused on all-cause withdrawal from biologic treatment among patients with chronic inflammatory rheumatoid disease.

A systematic review published in 2011 calculated that the rate of withdrawal for psoriatic arthritis patients using etanercept, adalimumab or infliximab is about 17% per year — a figure that includes patients who switch medications in hopes of greater efficacy or milder side effects as well as those who discontinue all biologic treatment.

“There does not appear to be any difference in withdrawal rates between etanercept and adalimumab. Infliximab appears to have a significantly higher withdrawal rate than etanercept,” the review authors wrote before noting that “Estimates of differences between drugs may be biased because infliximab was the first biologic to be marketed and may have been used on severe patients with low expectation of maintaining drug therapy.”

A 2011 analysis of Danish health data, one the other hand, found that patients stuck with infliximab significantly longer than other medications, but it found similar rates of treatment withdrawal among psoriasis patients who used biologics as a class.

Among patients who had never used anti-tumor necrosis factor-α (anti-TNF-α ) medications to treat their condition, the longest drug survival was observed for infliximab, followed by adalimumab (hazard ratio [HR] vs. infliximab, 3.70; 95% confidence interval [CI], 1.99 to 6.89) and etanercept (HR vs. infliximab, 3.18; 95% CI, 1.72 to 5.86). The 4-year drug survival, for such patients, was about 40% for etanercept or adalimumab and about 70% for infliximab, even though there was no difference in number of adverse events.

The study of Danish patients did not look to see whether socio-economic factors, demographics or other distinguishing patient characteristics influenced their decision to stop using a single drug. It focused, instead, on changing outcomes over time.

“The overall efficacy of anti-TNF-α drugs diminishes with time, as envisaged by the progressive loss of patient adherence to treatment,” the study authors wrote. “The major reasons for stopping treatment were loss of efficacy, followed by adverse events.”