Unintentional Nonadherence to Hydroxyurea Prevalent Among Sickle Cell Patients

Hydroxyurea is efficacious in managing sickle cell disease, yet adoption and adherence is low among patients.

Findings from a new study found that patient nonadherence was typically due to unintentional barriers than intention ones. Understanding the reasons behind treatment nonadherence can help healthcare providers have more tailored discussions with their patients regarding hydroxyurea as well as develop more nuanced interventions to address nonadherence factors.

Jason Hodges, PhD, MA, and colleagues employed the unintentional and intentional nonadherence framework to better understand the complexities behind patient choices that determine whether or not to adopt or stay on a treatment.

They conducted semi-structured interviews with 90 sickle cell disease patients who were participants in the Sickle Cell Disease Implementation Consortium (SCDIC). These interviews were completed across 5 of the 8 SCDIC sites and included patients with a mean age of 30.5 years. Female patients represented 57% of the participant population.

Among all interviewed participants, 57.8% indicated that they were currently taking hydroxyurea, 28.9% were former users of the medication, 13.3% have never used it but expressed familiarity with the medication.

They then divided adherence types into either intention or unintentional. Using a constructivist grounded theory approach, they discovered important themes that contributed to nonadherence. They further assigned these themes to either intentionality category.

For example, intentional themes included negative perceptions of hydroxyurea and aversion to taking any medications. Unintentional themes included forgetfulness and external influencers.

The investigators reported that, overall, participants more frequently endorsed barriers that fell into the unintentional nonadherence type (67.9%)—versus the intentional nonadherence type (31.1%).

Those who had formerly used hydroxyurea indicated 14 types of barriers to taking the medication. Of those barriers, 9 were considered unintentional nonadherence barriers. 

Among current users of the medication, 75.7% of the barriers were considered to be unintentional.

For all patients with any history of hydroxyurea use (87%), 69.9% endorsed unintentional barriers and 30.1% endorsed intentional ones.

On the contrary, patients with no history of medication use (13%) more commonly endorsed intentional nonadherence types (38.8%) than unintentional (31.1%).

Patients were also categorized into 3 phases of the adherence process—initiation, implementation, and discontinuation.

One of the most common barriers in the initiation phase was that patients were never introduced to the medication by their provider.

“Reasons that hydroxyurea may have not been introduced include provider barriers such as a lack of awareness leading to underprescribing, providers’ beliefs about a patient’s likelihood to be adherent, or providers with experience and knowledge making decisions that included consideration of a patient’s clinical characteristics,” the investigators wrote.

Among patients in the implementation phase—or those currently receiving hydroxyurea—the most common barriers leading to nonadherence included forgetfulness or a doctor’s/health team’s recommendation. These patients also tended to express negative beliefs about the medication.

The majority of patients in the discontinuation phase expressed changing attitudes and beliefs about hydroxyurea as their primary reason for treatment discontinuation. Few patients indicated their preference for chronic red cell transfusion, which either indicates a strong negative perception towards the medication or a considerable level of benefit attributed to transfusion.

“Adherence is challenging to address, and a greater understanding of complex barriers to adherence can inform strategies in the clinical and research settings for overcoming barriers,” the investigators concluded.

The study, “Intentional and unintentional nonadherence to hydroxyurea among people with sickle cell disease: a qualitative study,” was published online in Blood Advances.