Study Finds that Most Adherence Barriers to a Sickle Cell Therapy are Unintentional



In a new study of sickle cell disease patients, researchers found that nonadherence among patients in the study was largely due to unintentional barriers rather than intentional barriers.

Intentional vs. Unintentional Barriers

Intentional nonadherence refers to patients making deliberate decisions to not follow the prescribed treatment because, for example, they fear negative side effects or have doubts about the efficacy of the treatment. Unintentional nonadherence is when patients do not follow the prescribed treatment plan due to behaviors that are not deliberate, primarily forgetting to take the medication. This may be caused by the complexity of multiple drug regimes, competing life demands, etc.

Study Results

Researchers interviewed 90 sickle cell disease patients that were current or former users of the medication hydroxyurea (87%) or had never used hydroxyurea but were familiar with it (13%). Participants were asked about their reasons for not starting treatment, non-adherence to treatment, and discontinuation of therapy. Researchers found that 67.9% of the barriers that patients recounted were unintentional barriers; 31.1% of the barriers fell into the intentional barrier category. Among those taking hydroxyurea 75.7% of barriers sited were considered unintentional nonadherence barriers.


This study highlights the importance of understanding which barriers patients experience throughout their treatment journeys, the intentionality behind those barriers, and the behaviors that cause patients to not initiate or adhere to a therapy. Only once we have identified both the intentional and unintentional barriers can an adherence program successfully help patients overcome those barriers. 



1. Jason R. Hodges, Shannon M. Phillips, Sarah Norell, Chinonyelum Nwosu,...& Jerlym Porter; Intentional and unintentional nonadherence to hydroxyurea among people with sickle cell disease: a qualitative study. Blood Adv 2020; 4 (18): 4463–4473.

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