Objectives To determine the prevalence of inappropriate prescribing in elderly patients with polypharmacy admitted to a long-term care hospital (LTCH) and to evaluate the impact of an interdisciplinary pharmacotherapy quality programme on improvement of prescribing appropriateness.

Methods An interventional, longitudinal, prospective study was conducted in a Spanish LTCH (October 2013 to July 2014) including 162 elderly (≥70 years) patients with polypharmacy (≥5 medications). Pharmacists conducted the pharmacotherapy follow-up of patients with medication reconciliation, pharmacotherapeutic optimisation and educational interviews from admission to discharge. Reconciliation errors, potentially inappropriate medications (PIMs), potentially prescribing omissions (PPOs) and significant drug interactions rates were calculated. The impact of the programme was evaluated considering the difference between the inappropriateness score per patient (total number of reconciliation errors, PIMs, PPOs and significant drug interactions) before and after implementing pharmacotherapy recommendations.

Results At admission, 163 reconciliation errors (median(range), 1(1-6)) in 92 (56.8%) patients (65.6% drug omissions), 335 PIMs (2(1-6)) in 147 (90.7%) patients (39.3% use ≥2 anticholinergic drugs), 43 PPOs (1(1-3)) in 32 (19.8%) patients (48.5% statin omission) and 594 significant drug interactions (4(1-19)) in 130 (80.2%) patients were detected. After implementing pharmacotherapy recommendations, statistically significant reductions in admission reconciliation errors (8.3% to 0.1%), PIMs (17.0% to 12.2%), PPOs (2.2% to 0.7%) and significant drug interactions (30.2% to 26.8%) rates were found. The programme achieved a 31% improvement in prescribing appropriateness, with a statistically significant reduction in the inappropriateness score (6(IQR:4–9) to 4(IQR:2–7)).

Conclusion Reconciliation errors, PIMs and drug interactions are highly prevalent in elderly patients with polypharmacy admitted to an LTCH. This interdisciplinary pharmacotherapy quality programme seems to be a useful approach in the improvement of prescribing appropriateness in a high-risk older population.