Relationship Between Primary Percutaneous Coronary Intervention, Door-to-balloon Times, and Mortality for Heart Attack Patients Across England

Study Overview
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Brief Summary
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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. 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. Our study found that higher adjusted mortality associated with off-hours admissions for PPCI could be partly explained by differences in DTB times.

Official Title
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The Relationship Between Off-hours Admissions for Primary Percutaneous Coronary Intervention, Door-to-balloon Time and Mortality for Patients With ST-elevation Myocardial Infarction in England: a Registry-based Prospective National Cohort Study

Conditions
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Myocardial Infarction

Intervention / Treatment
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* Other: Standard Hospital Care


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: STEMI patients admitted from 1 January 2007 to 31 December 2012 STEMI patients aged over 18 years STEMI patients admitted directly to '24/7' PPCI-capable hospitals for PPCI Discharge diagnosis of STEMI Provision of PPCI based on initial reperfusion strategy Exclusion Criteria: Hospitals performing less than 20 procedures per year Hospitals performing PPCIs only during regular hours Interhospital transfers PPCIs conducted within 6 hours on hospital arrival

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Hospital Admitted STEMI Patients<br>The analytical cohort for this study consisted of STEMI patients aged over 18 years admitted directly to '24/7' PPCI-capable hospitals for PPCI. STEMI patients were identified based on their discharge diagnoses and were selected as having received PPCI according to their initial reperfusion strategy. Hospitals performing only sporadic PPCI procedures, which we defined as less than 20 procedures per year, and only performing PPCIs during regular hours were not included in the analysis. Interhospital transfers were not included in the analysis, and we limited our analysis to PPCIs conducted within 6 hours on hospital arrival on the assumption that patients with a DTB time beyond this did not receive PCI as a primary reperfusion strategy. The analysis was conducted for the time period for which data were available-1 January 2007 to 31 December 2012. We conducted a complete-case analysis. | Other: Standard Hospital Care<br>* We described patient characteristics using percentages for categorical data, means and SD or medians and IQRs for normally and non-normally distributed continuous variables, respectively. Statistical comparisons for differences in baseline characteristics among patients admitted during regular hours and off-hours were performed using χ2 tests for categorical variables, t-tests and Wilcoxon rank sum tests for normally and non-normally distributed continuous variables, respectively. DTB times were described using median and IQR based on time of admission. All p values were calculated as two-tailed analyses, using a significance level of 5%.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 30-day mortality |  | 30 days post-discharge | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| In-hospital mortality |  | Patient length of stay in hospital until discharge, an average of 3 days |