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The impact of hospital harm on length of stay, costs of care and length of person-centred episodes of care: a retrospective cohort study


Background — There is a lack of data in Canada on the longitudinal effects of adverse events that occur in hospital, specifically in the period after discharge. Our objective was to quantify the impact of adverse events on hospital length of stay, length of person-centred episodes of care (PCEs) and costs of PCEs, as well as their impact on the total health system.

Methods — We conducted a population-based, retrospective cohort study using linked health administrative databases. We included adults in Ontario who had an acute hospital admission between Apr. 1, 2015, and Mar. 31, 2016. We grouped hospital admissions into 1 of 9 episode types and used the Canadian Institute for Health Information methodology for hospital harm to measure adverse events. We specified generalized linear models to estimate the impact of hospital harm on the following: incremental length of index acute hospital admission, incremental length of the PCE, and incremental costs of the PCE.

Results — Out of 610 979 hospital admissions, 36 004 (5.9%) involved an occurrence of harm. The impact of harm on the incremental length of hospital stay ranged from 0.4 to 24.2 days (p < 0.001); the incremental length of the PCE ranged from 0.3 to 30.2 days (p < 0.001); and the incremental costs of the PCE ranged from $800 to $51 067 (p < 0.001). Total hospital days attributable to hospital harm amounted to 407 696, and the total attributable cost to the Ontario health system amounted to $1 088 330 376.

Interpretation — We found that experiencing harm in hospital significantly affects both in-hospital and post-discharge use of health services and costs of care, and constitutes an enormous expense to Ontario’s publicly funded health system.



Tessier L, Guilcher SJT, Bai YQ, Ng R, Wodchis WP. CMAJ. 2019; 191(32):E879-85. Epub 2019 Aug 12.

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