The prevalence, severity and nature of preventable patient harm across medical care settings: a systematic review and meta-analysis.

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We aimed to systematically quantify the prevalence, severity and nature of preventable patient harm across a range of medical settings globally.
Systematic review and meta-analysis of observational studies (mainly case record reviews).
We searched eight bibliographic databases including Medline, PubMed, PsycINFO, Cinahl and Embase, WHOLIS, Google Scholar and SIGLE from January 2000 to January 2019. The reference lists of eligible studies and other relevant systematic reviews were hand-searched.
Observational studies reporting preventable patient harm in medical care. The core outcomes were the prevalence, severity and types of preventable patient harm reported as percentages and their 95% confidence intervals. Data extraction and critical appraisal were undertaken by two reviewers working independently. Random-effects meta-analysis was employed followed by univariable and multivariable meta-regression. Heterogeneity was quantified using the I2 statistic, and publication bias was evaluated.
Of the 7,313 records identified, 69 studies involving 345,226 patients were included in the meta-analysis. The pooled prevalence for preventable patient harm was 6% (95% CI= 5 to 7). A pooled proportion of 14% (95% CI= 11 to 17) of preventable patient harm was severe or led to death. Incidents related to medication (25%, 95% CI=16 to 34) and other therapeutic management (24%, 95% CI=21 to 30) accounted for the largest proportion of preventable patient harm. Compared to general hospitals (where most evidence originated), preventable patient harm was more prevalent in advanced specialities (intensive care/surgery; regression coefficient b=0.05, 95% CI 0.03 to 0.08).
Around one in 20 patients are exposed to harm in medical care which is preventable. Although a focus on preventable patient harm has been encouraged by the international patient safety policy agenda, there are limited quality improvement practices specifically targeting incidents of preventable patient harm rather than overall patient harm (preventable and non-preventable). Developing and implementing evidence-based mitigation strategies specifically targeting preventable patient harm could lead to major service quality improvements in medical care which could also be more cost-effective.
Original languageEnglish
Article numberl4185
JournalBritish Medical Journal
Early online date17 Jul 2019
Publication statusPublished - 17 Jul 2019


  • preventable patient harm
  • patient safety
  • medical care settings
  • meta-analysis


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