Response in the first year of anti-TNF treatment appears to be a strong predictor of whether people with SpA will stay on treatment in the long-term, an observational study suggests.

The researchers from several rheumatology clinics in Greece say their findings suggest that close disease activity monitoring in the early years of treatment could be a valuable tool for predicting long-term outcomes.

The observational industry-sponsored study involved 1,077 patients with SpA participating in the Hellenic Registry of Biologic Therapies who started treatment with anti-TNFs between 2004 and 2014.

Results showed that 60% percent of the patients remained on treatment at five years and 49% at 10 years.

Having a diagnosis of AS and limited axial phenotype predicted longer drug adherence compared to a comparative analysis of people with PsA and undifferentiated SpA.

But achieving a major response during the first year of treatment in either axial or peripheral arthritis was the strongest predictor of remaining on therapy (HR 0.33 for ASDAS and HR 0.35 for DAS-28).

For the 37.5% of patients who did discontinue therapy, treatment inefficacy was the most frequent reason (43%) followed by adverse events (39%).

Male sex predicted higher treatment retention both for efficacy and safety reasons whereas the use of methotrexate was protective against treatment discontinuation for adverse events.

“To our knowledge, we are the first to report that clinical variables quantifiable early in the treatment course, such as ADAS-CRP inactive disease state and DAS28- remission state, could predict a 2 to 3.5 fold higher chance of 10-year drug survival in everyday clinical practice,” the research team wrote in their paper published in The Journal of Rheumatology.

“We support close disease activity monitoring as a valuable tool to predict long-term outcomes,” they concluded.