Three definitions of high users of inpatient services captured significantly different groups of patients. This has implications for targeting subgroups for intervention and highlights important considerations for selecting the most suitable definition for a given objective.

This study aimed to estimate the frequency of hospital adverse events (AEs) and explore the rate of AEs over time, and across and within hospital populations.Methods: Validated search terms were run in MEDLINE and EMBASE; gray literature and references of included studies were also searched. Studies of any design or language providing an estimate of AEs within the hospital were eligible. Studies were excluded if they only provided an estimate for a specific AE, a subgroup of hospital patients or children. Data were abstracted in duplicate using a standardized data abstraction form. Study quality was assessed using the Newcastle-Ottawa Scale. A random-effects meta-analysis estimated the occurrence of hospital AEs, and meta-regression explored the association between hospital AEs, and patient and hospital characteristics.Results: A total of 45,426 unique references were identified; 1,265 full-texts were reviewed and 94 studies representing 590 million admissions from 25 countries from 1961 to 2014 were included. The incidence of hospital AEs was 8.6 per 100 patient admissions (95% confidence interval [CI], 8.3 to 8.9; I 2 = 100%, P < 0.001). Half of the AEs were preventable (52.6%), and a third resulted in moderate/significant harm (39.7%). The most evaluated AEs were surgical AEs, drug-related AEs, and nosocomial infections. The occurrence of AEs increased by year (95% CI, −0.05 to −0.04; P < 0.001) and patient age (95% CI = −0.15 to −0.14; P < 0.001), and varied by country income level and study characteristics. Patient sex, hospital type, hospital service, and geographical location were not associated with AEs.Conclusions: Hospital AEs are common, and reported rates are increasing in the literature. Given the increase in AEs over time, hospitals should reinvest in improving hospital safety with a focus on interventions targeted toward the more than half of AEs that are preventable.

ObjectiveTo evaluate the validity of COVID-19 International Classification of Diseases, 10th Revision (ICD-10) codes and their combinations.DesignRetrospective cohort study.SettingAcute care hospitals and emergency departments (EDs) in Alberta, Canada.ParticipantsPatients who were admitted to hospital or presented to an ED in Alberta, as captured by local administrative databases between 1 March 2020 and 28 February 2021, who had a positive COVID-19 test and/or a COVID-19-related ICD-10 code.Main outcome measuresThe sensitivity, positive predictive value (PPV) and 95% CIs for ICD-10 codes were computed. Stratified analysis on age group, sex, symptomatic status, mechanical ventilation, hospital type, patient intensive care unit (ICU) admission, discharge status and season of pandemic were conducted.ResultsTwo overlapping subsets of the study population were considered: those who had a positive COVID-19 test (cohort A, for estimating sensitivity) and those who had a COVID-19-related ICD-10 code (cohort B, for estimating PPV). Cohort A included 17 979 ED patients and 6477 inpatients while cohort B included 33 675 ED patients and 18 746 inpatients. Of inpatients, 9.5% in cohort A and 8.1% in cohort B received mechanical ventilation. Over 13% of inpatients were admitted to ICU. The length of hospital stay was 6 days (IQR: 3–14) for cohort A and 8 days (IQR: 3–19) for cohort B. In-hospital mortality was 15.9% and 38.8% for cohort A and B, respectively. The sensitivity for ICD-10 code U07.1 (COVID-19, virus identified) was 82.5% (81.8%–83.2%) with a PPV of 93.1% (92.6%–93.6%). The combination of U07.1 and U07.3 (multisystem inflammatory syndrome associated with COVID-19) had a sensitivity of 82.5% (81.9%–83.2%) and PPV of 92.9% (92.4%–93.4%).ConclusionsIn Alberta, ICD-10 COVID-19 codes (U07.1 and U07.3) were coded well with high validity. This indicates administrative data can be used for COVID-19 research and pandemic management purposes.

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