Seasonality in surgical outcome data: a systematic review and narrative synthesis

Emma Spencer; Michael Berry; Peter Martin; Antonio Rojas-Garcia; S Ramani Moonesinghe

doi:10.1016/j.bja.2021.10.043

Seasonality in surgical outcome data: a systematic review and narrative synthesis

Br J Anaesth. 2022 Feb;128(2):321-332. doi: 10.1016/j.bja.2021.10.043. Epub 2021 Dec 4.

Authors

Emma Spencer¹, Michael Berry², Peter Martin³, Antonio Rojas-Garcia⁴, S Ramani Moonesinghe⁵

Affiliations

¹ University College London Hospital, London, UK.
² King's College NHS Foundation Trust, London, UK.
³ Department of Applied Health Research, University College London, London, UK.
⁴ Public Health Policy Evaluation Unit, School of Public Health, Imperial College London, London, UK.
⁵ Centre for Perioperative Medicine, Research Department for Targeted Intervention, Division of Surgery and Interventional Science, University College London, London, UK; University College London Hospitals, National Institute for Health Research Biomedical Research Centre, London, UK. Electronic address: ramani.moonesinghe@nhs.net.

PMID: 34872715
DOI: 10.1016/j.bja.2021.10.043

Abstract

Background: Seasonal trends in patient outcomes are an under-researched area in perioperative care. This systematic review evaluates the published literature on seasonal variation in surgical outcomes worldwide.

Methods: MEDLINE, Embase, Cochrane, CINHAL, and Web of Science were searched for studies on major surgical procedures, examining mortality or other patient-relevant outcomes, across seasonal periods up to February 2019. Major surgery was defined as a procedure requiring an overnight stay in an inpatient medical facility. We included studies exploring variation according to calendar and meteorological seasons and recurring annual events including staff turnover. Quality was assessed using an adapted Downs and Black scoring system.

Results: The literature search identified 82 studies, including 22 210 299 patients from four continents. Because of the heterogeneity of reported outcomes and literature scope, a narrative synthesis was undertaken. Mass staff changeover was investigated in 37 studies; the majority (22) of these did not show strong evidence of worse outcomes. Of the 47 studies that examined outcomes across meteorological or calendar seasons, 33 found evidence of seasonal variation. Outcomes were often worse in winter (16 studies). This trend was particularly prominent amongst surgical procedures classed as an 'emergency' (five of nine studies). There was evidence for increased postoperative surgical site infections during summer (seven of 12 studies examining this concept).

Conclusion: This systematic review provides tentative evidence for an increased risk of postoperative surgical site infections in summer, and an increased risk of worse outcomes after emergency surgery in winter and during staff changeover times.

Clinical trial registration: PROSPERO CRD42019137214.

Keywords: July effect; perioperative outcomes; seasonal variation; seasonality; staff changeover; surgical outcomes; winter pressures.

Publication types

Systematic Review

MeSH terms

Humans
Perioperative Care / methods
Risk
Seasons*
Surgical Procedures, Operative / adverse effects
Surgical Procedures, Operative / methods*
Surgical Wound Infection / epidemiology*
Treatment Outcome