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Hospital admissions associated with medication non-adherence: a systematic review of prospective observational studies
  1. Pajaree Mongkhon1,2,
  2. Darren M Ashcroft3,4,
  3. C Norman Scholfield1,
  4. Chuenjid Kongkaew1,5
  1. 1 Centre for Safety and Quality in Health, Faculty of Pharmaceutical Sciences, Department of Pharmacy Practice, Naresuan University, Muang, Thailand
  2. 2 School of Pharmaceutical Sciences, University of Phayao, Muang, Phayao, Thailand
  3. 3 Centre for Pharmacoepidemiology and Drug Safety, School of Health Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre (MAHSC), University of Manchester, Manchester, UK
  4. 4 NIHR Patient Safety Translational Research Centre Greater Manchester, University of Manchester, Manchester, UK
  5. 5 Department of Practice and Policy, Research Department of Practice and Policy, School of Pharmacy, UCL, London, UK
  1. Correspondence to Dr Chuenjid Kongkaew, Centre for Safety and Quality in Health, Faculty of Pharmaceutical Sciences, Department of Pharmacy Practice, Naresuan University, Muang 65000, Thailand; chuenjid{at}


Background Medication non-adherence in ambulatory care has received substantial attention in the literature, but less so as it affects acute care. Accordingly, we aimed to estimate the frequency with which non-adherence to medication contributes to hospital admissions.

Methods We searched the Cochrane Library, EMBASE, Cumulative Index to Nursing and Allied Health Literature, International Pharmaceutical Abstracts and PubMed (until December 2017) to identify prospective observational studies that examined prevalence rates of hospital admissions associated with medication non-adherence. A quality assessment was performed using an expanded Crombie checklist. Data extraction covered patterns, circumstances, and patient and other key characteristics of non-adherence. Pooled estimates were obtained using a random-effect model.

Results Of 24 included studies, 8 were undertaken in North America, 7 from Europe, 6 from Asia and 3 from Australia. Most studies (79%) were rated as low risk of bias. All but three studies used combination measures to detect non-adherence, but approaches to assess preventability varied considerably. Across the studies, there was high heterogeneity among prevalence estimates (χ2=548, df 23, p<0.001, I2=95.8%). The median prevalence rate of hospital admissions associated with non-adherence was 4.29% (IQR 3.22%–7.49%), with prevalence rates ranging from 0.72% to 10.79%. By definition, almost all of these admissions were considered preventable. The underlying causes contributing to these admissions included medication cost and side effects, and non-adherence most often involved cardiovascular medicines.

Conclusions Hospital admissions associated with non-adherence to medication are a common problem. This systematic review highlights important targets for intervention. Greater attention could be focused on adherence to medication during the hospital stay as part of an enhanced medication reconciliation process. Standardisation in study methods and definitions is needed to allow future comparisons among settings; future studies should also encompass emerging economies.

  • adverse events, epidemiology end detection
  • hospital medicine
  • medication safety
  • patient Safety
  • compliance

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  • Contributors DMA and CK conceptualised the study. PM and CK performed the searches, screened all the titles and abstracts for compliance with the inclusion criteria, reviewed full-text articles of the potential studies, and completed data extraction. All included studies were assessed for methodological quality by PM and cross-checked by CK. PM and CK drafted the manuscript. CNS, DMA and CK extensively revised the manuscript. All authors have read and approved the final manuscript.

  • Funding Financial support from The Thailand Research Fund through the Royal Golden Jubilee PhD Program (Grant No PHD/0197/2557) and Naresuan University Research Fund (R2559C244) is gratefully acknowledged.

  • Competing interests None declared.

  • Patient consent Not required.

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