The role of executive functioning and prospective memory in subjective and objective measures of medication adherence among adults with type 2 diabetes

Abstract

Background: Research indicates high rates of poor medication adherence in diabetes. There is some evidence linking medication adherence with neuropsychological functioning, but further research is required to replicate findings in adults with type 2 diabetes. To extend this area of inquiry, the current study examined the association of multiple domains of executive functioning (EF) and prospective memory (ProM; subjective and objective measures) with medication adherence (subjective and objective measures). Methods: The sample consisted of 104 participants with type 2 diabetes mellitus who were recruited through Albert Einstein College of Medicine or Montefiore Medical Center. Objective Medication Event Monitoring System (MEMS) data, validated adherence self-ratings, neuropsychological test data, and Hemoglobin Al C (glycemic control) were collected. Results: Both measures of adherence were equivalently correlated with Al C (ps<.05). Linear regressions showed no significant relationships between EF and adherence after controlling for age, education, and insulin prescription. ProM was not associated with MEMS, but was significantly associated with self-rated adherence (beta=-.35, p=.004). However, EF was a significant moderator of this effect (beta=1.17, p=.020). Post-hoc probing showed there was no significant relationship between ProM and self-rated adherence at high levels of EF. However, at low levels of EF, ProM and adherence were significantly related (beta=-.43, p=.010). Conclusions: Results demonstrated that higher levels of ProM were closely linked to validated patient reports of medication adherence in type 2 diabetes, particularly when EF was impaired. This suggested that individuals in our study were likely to rely on a mechanism of ProM involving a spontaneous, reflexive associative memory system rather than the strategic process that demands more cognitive resources like executive functioning for the medication-taking task. Moreover, a high level of executive functioning may help compensate for any difficulties in prospective memory; however, the lack of a relationship between EF and adherence makes it hard to fully understand this relationship and further investigation with more comprehensive measures of EF is needed. Our findings have an important clinical implication for improving medication adherence by implementing specific strategies for prospective memory in type 2 diabetes population.