I would like to share with you the abstract and highlights of an interesting publication about adherence.
This is the first published study of these variables, and it was supported by research funding from Novartis to Matrix45.
Prevalence, determinants, and outcomes of nonadherence to imatinib therapy in patients with chronic myeloid leukemia: The ADAGIO study
Blood-2008-12-196543, apr 6 2009
Imatinib mesylate (imatinib) has been shown to be highly efficacious in the treatment of chronic myeloid leukemia (CML). Continuous and adequate dosing is essencial for optimal outcomes and with imatinib treatment possibly being life-long, patient adherence is critical. The ADAGIO study aimed to assess prospectively over a 90-day period the prevalence of imatinib nonadherence in CML patients; to develop a multivariate canonical correlation model of how various determinants may be associated with adherence levels. A total of 202 patients were recruited from 34 centers in Belgium, of whom 169 were evaluated. One-third of patients were considered to be nonadherent. Only 14.2% of patients were perfectly adherent with 100% of prescribed imatinib taken. On average, patients with suboptimal response had significantly higher mean percentages of imatinib not taken (23.2%) than did those with optimal response (7.3%). Nonadherence is more prevalent than patients, physicians, and family members believe it is, and therefore should be assesed routinely. It is associated with poorer response to imatinib. Several determinants may serve as alert signals, many of which are clinically modifiable.
1) WHO defines patient adherence as “the extent to which a person’s behavior corresponds whith the agreed recommendations of a healthcare provider”
The definition is very relevant in this study because after measuring the self perception of the patient in regards to adherence it was found that there is a significant difference between what patients believe (most of the patients had the perception that they were adherent) and what patients do (only 14.2% of the patients were adherent). The research suggests that assessment of patient’s adherence behavior is more important than their self perceptions of adherence.
2) Being more knowledgeable about disease and treatment, showing greater self-efficacy in long term medication behavior, and having at least a secondary school education are all associated with better adherence behavior. Having to take more medications on a daily basis is also associated with imatinib adherence.
3) On average, patients with a lesser response (cytogenetic) had taken between 74.0% and 76.8% of prescribed dose, compared to 89.9% and 92.7% for patients with a better response. This constitutes strong initial evidence that nonadherence to imatinib treatment is associated with poorer treatment outcomes, and that 100% adherence with imatinib treatment is an essencial clinical target.
4) Based on self-report and pill count, this sample exhibited higher nonadherence than reported in a meta analysis of 569 studies across 17 diseases (24.8%), including 65 studies in cancer (79.1%). This is surprising because of the severity of CML as a disease, the high efficacy of imatinib, its tolerability profile relative to other antineoplasic agents, the high morbidity and mortality of CML prior to the advent of imatinib, and the convenience of oral administration. Those factors should be convincing reasons for CML patients to be highly adherent.
5) There was virtually no relationship between adherence to imatinib and time since CML diagnosis, lenght of imatinib treatment, adverse events, and patient-reported symptoms and their bothersomeness.