Prevalence and determinants of pharmacy shopping behaviour

Background and objective: Discontinuity of care bears the risk of medication errors and poor clinical outcomes. Little is known about the continuity of care related to pharmacies. Therefore, we studied the prevalence and determinants of pharmacy shopping behaviour in the Netherlands.Methods: Beneficiaries from a Dutch pharmacy claims database who had visited two or more pharmacies in 2001 were indicated as 'shoppers' (n = 45 805). A random sample was taken from all the other beneficiaries who had received at least one prescription: 'non-shoppers' (n = 45 805). Shoppers were classified as light (all patients who visited more than one pharmacy at least once in 2001, except for patients defined as heavy or moderate shoppers), moderate (visited 3 or 4 pharmacies and had proportion of prescriptions elsewhere > 10% and number of prescriptions elsewhere > 10) or heavy (visited 5 or more pharmacies and had proportion of prescriptions elsewhere > 10% and number of prescriptions elsewhere > 10). Determinants of shopping behaviour were investigated as well as the association between any dispensing of Anatomical Therapeutic Chemical (ATC) classes of drugs and this behaviour.Results: 10.8% beneficiaries were identified as shoppers: 98.8% 'light shoppers', 1.0% 'moderate shoppers' and 0.2% 'heavy shoppers'. Female gender [odds ratio (OR)(adj) 1.2; 95% confidence interval (CI) 1.1-1.2], younger age (ORadj 1.7; 95%CI 1.7-1.8), the use of >= 3 drugs (ORadj 2.9; 95%CI 2.8-3.0) and visiting different kind of prescribers (ORadj 2.4; 95%CI 2.4-2.5) were associated with shopping behaviour. Shoppers more frequently received at least one prescription for systemic anti-infectives (51.7% vs. 30.8%; OR 2.4; 95%Cl 2.3-2.5) and for nervous system drugs (46.2% vs. 29.3%; OR 2.1; 95%Cl 2.0-2.1).Conclusions: Pharmacy shopping behaviour is limited in the Netherlands. However, it may put the patient at risk for unintentional problems, such as drug-drug interactions with anti-infectives. A small proportion of patients exhibit possibly intentional shopping behaviour with psychotropic drugs.