Background Unplanned readmissions to hospital are used in many healthcare systems as a quality indicator of care. Identifying patients at risk of readmission is difficult; existing prediction tools are only moderately sensitive. Correlations exist between certain medicines and emergency readmission, but it is not known whether the association is direct or indirect.

Objectives To determine whether person-centred pharmaceutical care bundles, comprising individualised medicines information, risk management and/or support in taking medicines, might prevent unplanned readmissions by improving adherence and reducing avoidable harm from prescribed medications.

Methods We designed and implemented person-centred pharmaceutical care bundles for patients who were socially isolated and/or on high-risk medicines on one older people's medical ward for 1 year from February 2013. Another ward with similar patient demographics, service characteristics and a standard clinical pharmacy service was used as a comparator in a prospective cohort study. Readmission rates were retrospectively studied for 12 months before the intervention and during the 12-month intervention period.

Results The readmission rates for the intervention and control wards in the 12 months before the intervention were not significantly different. During the intervention period, the readmission rate was significantly lower on the intervention ward (69/418) than on the control ward (107/490; 17% vs 22%, p<0.05, z=2.05, two-sample z test for difference in proportions of unrelated samples).

Conclusions Person-centred pharmaceutical care bundles were significantly associated with reduced risk of emergency hospital readmission in this study. Further evaluation of the model is warranted.