A study published in Haemophilia revealed significant discrepancies between subjective and objective measures of adherence to prophylaxis in patients with severe hemophilia.

Researchers conducted a cross‐sectional study at 2 hemophilia treatment centers in the state of São Paulo, Brazil, between August 2015 and January 2016. The investigators interviewed patients (or primary caregivers) to assess their self‐perceived adherence to treatment, measured using a 5-point Likert scale, and estimated the number of clotting factor concentrate (CFC) infusions they had missed during the last period of CFC dispensation. Interview results were then compared with the number of CFC vials returned by participants to the treatment center as an objective measure of adherence based on the frequency of prophylaxis infusions and dosing deviations.

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Data from 29 eligible male patients were included in the study. The participants’ self‐perceived degree of adherence was not significantly correlated with the objective classification of adherence (rho, 0.10; 95% CI, -0.28 to 0.46; P =.61). Similarly, participant adherence based on self-reported estimates of missed CFC doses was not significantly correlated with the objective classification of adherence (rho, 0.32; 95% CI, -0.01 to 0.59; P =.11). However, a moderate correlation existed between participant adherence based on self-reported estimates of missed CFC doses and the number of CFC vials returned (rho, 0.56; 95% CI, 0.24-0.77; P =.003).

According to the authors, these discrepancies “likely reflect the influence of social desirability bias in self‐reported measures and different concepts of adherence between patients/caregivers and hemophilia experts.” Furthermore, they hypothesized that studies of adherence to prophylaxis that rely solely on self-reported information may largely overestimate the degree of patient adherence.

Reference

1.     Guedes VG, Corrente JE, Farrugia A, Thomas S, Wachholz PA, Oliveira Vidal EI. Comparing objective and self‐reported measures of adherence in haemophilia [published online July 19, 2019]. Haemophilia. doi:10.1111/hae.13811