Prescription errors in older individuals with an intellectual disability: Prevalence and potential risk factors

OBJECTIVE: To determine the prevalence and potential risk factors of prescription errors in older individuals (≥ 50 years of age) with an intellectual disability (ID). DESIGN: Cross-sectional study. METHODS: The study population consisted of older individuals (≥ 50 years) with an ID with one or more medication orders, from the data file of the Erasmus MC Healthy Ageing and ID study. The medication used at the time of measurement was screened for errors by a hospital pharmacist/clinical pharmacologist and a Master's student pharmacy, using consensus methodology. Participants with one or more prescription errors were compared to participants without prescription errors by multivariate logistic regression, in order to identify potential risk factors. RESULTS: Among 600 randomly selected participants, 446 prescription errors were found affecting 285 participants. The prevalence of participants with at least one prescription error was 48% (CI95 44-52%). Variables independently associated with prescription errors were age (ORadj 1.03, CI95 1.01-1.06), ID level (moderate: ORadj 0.48, CI95 0.31-0.74; severe: ORadj 0.56, CI95 0.32-0.98), body mass index (ORadj 1.04, CI95 1.01-1.08), frailty index (0.39-0.54: ORadj 2.40, CI95 1.21-4.77; ≥ 0.55: ORadj 3.37. CI95 1.03-11.02), number of medicines (five or more: ORadj 8.06, CI95 5.59-11.62) and use of medicines acting on the central nervous system (one or more: ORadj 3.34, CI95 2.35-4.73). CONCLUSION: The prevalence of prescription errors in older individuals with an ID is 48%. The identified risk factors can help to focus interventions on high risk patients.