Regimen complexity and medication nonadherence in elderly patients.

Objective: To assess whether the number of daily administrations of individual drugs, as a measure of regimen complexity, contributes to the profile of an elderly patient who adheres poorly to the prescribed therapy.

Population: Six hundred ninety patients over 64 years who were consecutively admitted to 11 acute medical care and three long term/rehabilitation wards in Italy.

Main Outcome Measure: Self-reported adherence to drugs taken at home before admission was measured by a single question assessment for each listed drug supplemented with a latter question about the circumstances of the missed administration. For cognitively impaired patients the question was put to patients' relatives or caregivers.

Methods: A structured multidimensional assessment was performed to identify nonadherence and its potential correlates. Correlates of nonadherence were identified by multivariable logistic regression.

Results: We recorded 44 cases (6.4%) of nonadherence to at least one drug. Being assisted by foreign caregivers (OR 2.17; 95% CI 1.02-4.63) and the use of at least one multiple daily dosing drug (OR 2.99; 95% CI 1.24-7.17) were significant independent correlates of medication nonadherence, while age, selected indexes of frailty and the cumulative number of prescribed drugs were not.

Conclusion: Regimen complexity and type of assistance are independent correlates of medication nonadherence.