Adherence to subcutaneous biological therapies in patients with inflammatory rheumatic diseases and inflammatory bowel disease: a systematic review.

Aim: To assess adherence to subcutaneous biologicals in adults with inflammatory rheumatic diseases or inflammatory bowel disease and evaluate factors possibly associated with adherence. Materials & methods: Systematic searches were conducted of main databases from January 2000 to June 2019. Results: 41 articles (32 full papers and nine abstracts) were included in the review. Among studies which used a medication possession ratio threshold of ≥80% as the end point, adherence varied from 28.8 to 89.4%. Possible predictors of adherence were older age, professional or family member support, belief in medication necessity, lower concerns about medication and monthly versus weekly administration. Conclusion: Considerable variability in adherence rates across published studies reflects study heterogeneity and the absence of a 'gold standard' to measure adherence.