Association between Multi-Dose Drug Dispensing and Quality of Drug Treatment – A Register-Based Study

BACKGROUND: In the elderly in Scandinavia, multi-dose drug dispensing (MDD) is a common alternative to ordinary prescriptions (OP). MDD patients receive their drugs in unit bags, one for each dose occasion. The prescribing procedure differs between MDD and OP. The aim of the present study was to investigate the association between MDD and quality of drug treatment (QDT). METHODOLOGY/PRINCIPAL FINDINGS: A cross-sectional study was performed of all inhabitants in Region Västra Götaland alive on December 31st 2007, aged ≥65 years, with ≥1 prescribed drug and ≥2 health care visits for ≥2 diagnoses for obstructive pulmonary disease, diabetes mellitus, and/or cardiovascular disease in 2005–2007 (n = 24,146). For each patient, drug treatment on December 31st 2007 was estimated from drugs registered in the Swedish Prescribed Drug Register. QDT was evaluated according to established quality indicators (≥10 drugs, Long-acting benzodiazepines, Drugs with anticholinergic action, ≥3 psychotropics, and Drugs combinations that should be avoided). Logistic regression, with adjustments for age, sex, burden of disease, and residence, was performed to investigate the association between MDD and QDT. Mean age was 77 years, 51% were females, and 20% used MDD. For all quality indicators, the proportion of patients with poor QDT was greater in patients with MDD than in patients with OP (all P<0.0001). Unadjusted and adjusted odds ratios (95% confidence intervals) for poor QDT (MDD patients vs. OP patients) ranged from 1.47 (1.30–1.65) to 7.08 (6.30–7.96) and from 1.36 (1.18–1.57) to 5.48 (4.76–6.30), respectively. CONCLUSIONS/SIGNIFICANCE: Patients with MDD have poorer QDT than patients with OP. This cannot be explained by differences in age, sex, burden of disease, or residence. These findings must be taken into account when designing alternative prescribing systems. Further research is needed to evaluate causative factors and if the findings also apply to other dose dispensing systems.