Black race, polypharmacy, and increasing age were associated with poor adherence to lenalidomide in older patients with newly-diagnosed multiple myeloma, according to an analysis of Surveillance, Epidemiology, and End Results (SEER)–Medicare linked data.
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The objective of the study was to examine factors affecting adherence in older adults who received lenalidomide.
Of 793 patients diagnosed and treated between 2007 and 2014, 302 (38%) had poor adherence to lenalidomide, reported Hira Mian, MD, of McMaster University, Hamilton, Ont., and colleagues. The findings were published in Clinical Lymphoma, Myeloma & Leukemia.
The researchers studied patients 65 years and older who had received at least two lenalidomide prescriptions in the first year following diagnosis. Only patients who filled a prescription for lenalidomide within 60 days of a myeloma diagnosis were included.
The median age of the patients was 73 years; 43% were aged 75 years or older. Most of the patients included in the analysis were white.
The medication possession ratio, defined as the “ratio of the number of days the patient had pills in their possession to the number of days in the observation period,” was used to evaluate adherence to therapy. A ratio of less than 90% was deemed poor adherence by the researchers.
After analysis, the researchers found that black race (adjusted odds ratio, 1.72; P = .022), polypharmacy (aOR, 1.04 per drug; P = .008), and increasing age (aOR, 1.03 per year; P = .024) were all significantly associated with poor adherence to lenalidomide.
The mean medication possession ratio among study patients was 89.5%. Overall, 38% of patients in the study had poor adherence to lenalidomide, while just 7% of patients in the study had a medication possession ratio of 100%, indicating “perfect adherence.”
There was a trend toward inferior overall survival among patients with poor adherence to lenalidomide, but it was not statistically significant (hazard ratio 1.10, 95% confidence interval, 0.88-1.38).
“Our study emphasizes the need for both better clinical monitoring of adherence and for future prospective studies in accurately understanding the rates and predictors of adherence while simultaneously developing strategies for improving adherence for patients that are at high risk of nonadherence,” the researchers wrote.
The National Institutes of Health funded the study. No conflicts of interest were reported.
SOURCE: Mian H et al. Clin Lymphoma Myeloma Leuk. 2019 Oct 9. doi: 10.1016/j.clml.2019.09.618.