Background The degree to which elevated mortality associated with weekend or night-time hospital admissions reflects poorer quality of care (‘off-hours effect’) is a contentious issue. We examined if off-hours admissions for primary percutaneous coronary intervention (PPCI) were associated with higher adjusted mortality and estimated the extent to which potential differences in door-to-balloon (DTB) times—a key indicator of care quality for ST elevation myocardial infarction (STEMI) patients—could explain this association.
Methods Nationwide registry-based prospective observational study using Myocardial Ischemia National Audit Project data in England. We examined how off-hours admissions and DTB times were associated with our primary outcome measure, 30-day mortality, using hierarchical logistic regression models that adjusted for STEMI patient risk factors. In-hospital mortality was assessed as a secondary outcome.
Results From 76 648 records of patients undergoing PPCI between January 2007 and December 2012, we included 42 677 admissions in our analysis. Fifty-six per cent of admissions for PPCI occurred during off-hours. PPCI admissions during off-hours were associated with a higher likelihood of adjusted 30-day mortality (OR 1.13; 95% CI 1.01 to 1.25). The median DTB time was longer for off-hours admissions (45 min; IQR 30–68) than regular hours (38 min; IQR 27–58; p<0.001). After adjusting for DTB time, the difference in adjusted 30-day mortality between regular and off-hours admissions for PPCI was attenuated and no longer statistically significant (OR 1.08; CI 0.97 to 1.20).
Conclusion Higher adjusted mortality associated with off-hours admissions for PPCI could be partly explained by differences in DTB times. Further investigations to understand the off-hours effect should focus on conditions likely to be sensitive to the rapid availability of services, where timeliness of care is a significant determinant of outcomes.
- Healthcare quality improvement
- Health policy
- Duty Hours/Work hours
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Contributors EM, SJ and SS-V designed the paper. SJ, SS-V and FC extracted the data. SJ conducted the statistical analyses. SJ and SS-V wrote the manuscript. FC reviewed the manuscript. HMK and EM contributed to the interpretation of results and provided critical review of the paper. All authors have approved the final version of the paper.
Funding This research was funded by LSE Health and the National Institute for Health Research (NIHR) Imperial Patient Safety Translational Research Centre. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health and Social Care.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval Ethical approval was not required by our university for this study, as confirmed by the internal Research Ethics Review conducted as part of the Healthcare Quality Improvement Partnership (HQIP) data request submission and NHS Health Research Authority ethics review tool for health research in the UK.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement No data are available. Additional information from the study (such as full results from sensitivity analyses, statistical programming) are available from the corresponding author.
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