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Economic impact of potentially inappropriate prescribing and related adverse events in older people: a cost-utility analysis using Markov models
  1. Frank Moriarty1,
  2. Caitriona Cahir2,
  3. Kathleen Bennett2,
  4. Tom Fahey1
  1. 1 HRB Centre for Primary Care Research, Department of General Practice, Royal College of Surgeons in Ireland, Dublin, Ireland
  2. 2 Division of Population Health Sciences, Royal College of Surgeons in Ireland, Dublin, Ireland
  1. Correspondence to Dr Frank Moriarty; frankmoriarty{at}rcsi.ie

Abstract

Objectives To determine the economic impact of three drugs commonly involved in potentially inappropriate prescribing (PIP) in adults aged ≥65 years, including their adverse effects (AEs): long-term use of non-steroidal anti-inflammatory drugs (NSAIDs), benzodiazepines and proton pump inhibitors (PPIs) at maximal dose; to assess cost-effectiveness of potential interventions to reduce PIP of each drug.

Design Cost-utility analysis. We developed Markov models incorporating the AEs of each PIP, populated with published estimates of probabilities, health system costs (in 2014 euro) and utilities.

Participants A hypothetical cohort of 65 year olds analysed over 35 1-year cycles with discounting at 5% per year.

Outcome measures Incremental cost, quality-adjusted life years (QALYs) and incremental cost-effectiveness ratios with 95% credible intervals (CIs, generated in probabilistic sensitivity analysis) between each PIP and an appropriate alternative strategy. Models were then used to evaluate the cost-effectiveness of potential interventions to reduce PIP for each of the three drug classes.

Results All three PIP drugs and their AEs are associated with greater cost and fewer QALYs compared with alternatives. The largest reduction in QALYs and incremental cost was for benzodiazepines compared with no sedative medication (€3470, 95% CI €2434 to €5001; −0.07 QALYs, 95% CI −0.089 to –0.047), followed by NSAIDs relative to paracetamol (€806, 95% CI €415 and €1346; −0.07 QALYs, 95% CI −0.131 to –0.026), and maximal dose PPIs compared with maintenance dose PPIs (€989, 95% CI -€69 and €2127; −0.01 QALYs, 95% CI −0.029 to 0.003). For interventions to reduce PIP, at a willingness-to-pay of €45 000 per QALY, targeting NSAIDs would be cost-effective up to the highest intervention cost per person of €1971. For benzodiazepine and PPI interventions, the equivalent cost was €1480 and €831, respectively.

Conclusions Long-term benzodiazepine and NSAID prescribing are associated with significantly increased costs and reduced QALYs. Targeting inappropriate NSAID prescribing appears to be the most cost-effective PIP intervention.

  • elderly
  • medications
  • appropriateness
  • economic evaluation
  • stopp

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Footnotes

  • Twitter @FrankMoriarty

  • Contributors FM, CC, KB and TF contributed to the conception and design of this study. FM collected the data inputs used and carried out the statistical analysis. All authors interpreted the data. The manuscript was drafted by FM and all authors were involved in the critical revision and approval of the final manuscript. FM is the guarantor.

  • Funding All authors have declared support from the Health Research Board (HRB) in Ireland through grant no. PHD/2007/16 (FM), grant no. HRC/2014/1 (TF) and grant no. RL/15/1579 (CC and KB) for this work.

  • Competing interests None declared.

  • Patient consent Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement Markov models coded in Microsoft Excel are available at https://doi-org.ezproxy.u-pec.fr/10.6084/m9.figshare.5818251.v1 and data inputs are included in the technical appendix (online supplementary appendix table A1).