Adherence of patients with type 2 diabetes mellitus to medications: the role of risk preferences.

OBJECTIVE: To examine whether risk tolerance is associated with adherence to oral hypoglycemic agents (OHAs).

METHODS: We performed a cross-sectional study among adult patients with type 2 diabetes mellitus (n = 308) presenting for routine out-patient visits, using validated questionnaires to estimate: risk preferences (risk-seeking, risk averse, risk neutral), motivation, self-efficacy, impulsivity, perception of the disease and of the interpersonal process of care, demographic and socioeconomic characteristics; computerized patient medical records to estimate disease severity and a computerized database for retrieval of medication adherence, 1 year before the interview. Adherence was estimated using prescription-based measures of proportion of days covered (PDC). Concurrent adherence was calculated as: PDC with ≥1 OHAs; average PDC; PDC of ≥80% for all OHAs.

RESULTS: Multivariable ordered logit model revealed that compared to others, risk-seeking patients had lower PDC with ≥1 OHAs (β = -0.50, p ≤ .1). Specifically, risk-seeking patients were 11.2 percentage points less likely to have ≥80% of the follow-up period covered with ≥1 OHAs available (p ≤ .1). In addition, risk-seeking patients had lower average PDC (β = -0.85, p ≤ .05). Specifically, these patients were 19.5 percentage points less likely to have an average PDC of ≥80% (p ≤ .05). Multivariable logistic model revealed that risk-seeking was associated with lower probability of having PDC ≥80% for all OHAs in the follow-up period (OR; 90% CI: 0.59; 0.35-0.97).

CONCLUSIONS: Risk-seeking patients are less adherent to OHA medications. Identifying these patients may enable practitioners to proactively tailor strategies to improve their adherence and health outcomes.