In a recent systematic review of studies evaluating adherence to iron chelation therapy (ICT) in young patients with thalassemia, researchers found a lack of consensus on the meaning of adherence and difficulty in comparing adherence rates between studies. However, they did identify some trends in reports, such as possible predictors of ICT adherence and outcomes associated with adherence. The findings of this review were reported in the journal Annals of Medicine.
The researchers had a few objectives with this review. They aimed to evaluate ICT adherence in children and adolescents with thalassemia, and to identify methods used to measure adherence. Finding predictors of adherence and assessing health outcomes associated with adherence were other study aims.
The review was based on literature searches involving multiple databases for articles related to ICT and thalassemia that were published between 1980 and 2020. The evaluated patient population was children and adolescents. Included studies addressed adherence or compliance and were based on original research.
The researchers found 543 publications, of which 36 articles were eligible for analysis based on inclusion and exclusion criteria. Recruitment was through a clinic in each included study. Among possible chelators, deferoxamine and deferasirox were the most commonly evaluated chelators.
Among evaluable studies, thresholds used to define adherence or compliance varied. Among methodologies for evaluating adherence, patient self-reporting or pill count were the most commonly used methods to determine adherence, and these 2 methods were used in 15 studies each, or 41.7% of studies each. Less often-used methods for assessing adherence were subcutaneous medication monitoring, used in 5 studies, or prescription refill history, which was used in 4 studies. Adherence was assessed based on parent reporting or physician/provider reporting in 2 studies each.
Across studies, adherence was evaluated either as categories that reflect degrees of adherence (29 studies), or it was based on a percentage of prescribed medication (7 studies). In studies using percentages for adherence, the median adherence rate was 89.5%, and rates of adherence ranged from 57% to 98.4%.
Factors linked to adherence were reported in 29 studies. Some factors that were considered predictors of ICT adherence included type of chelator, age, side effects/discomfort, psychological issues, family support, and others. However, studies differed in terms of which factors were associated with adherence. The researchers also found that adherence in this population showed associations with lower serum ferritin levels and with better outcomes for cardiac, hepatic, psychoneurological, and endocrine function in some studies.
“In conclusion, due to a lack of clinical consensus on what adherence is and how it is defined, it is difficult to compare the adherence reporting of different studies,” the researchers concluded in their report. However, they did consider the studies included in this analysis to indicate some factors were correlated with adherence in this population, which could be useful for guiding communication between physicians and patients.
Reddy PS, Locke M, Badawy SM. A systematic review of adherence to iron chelation therapy among children and adolescents with thalassemia. Ann Med. 2022;54(1):326-342. doi:10.1080/07853890.2022.2028894