Myocardial Infarction as the First Manifestation of Coronary Heart Disease: Rates of Heralded and Unheralded Myocardial Infarction
Some myocardial infarctions (MI) occur as the first manifestation of coronary artery disease. These are termed 'unheralded' events as they have not been preceded by other forms of coronary artery disease. Unheralded MIs are important because of the high likelihood of missed opportunities for prevention. The proportion of MIs that are 'unheralded' is unknown.
This study aims to quantify the proportion of MIs that occur 'unheralded' and also give an estimate of the incidence of 'unheralded' MI in the UK, compared to 'heralded' MI and those with angina of recent onset (MIs with premonitory symptoms).
|Study Design:||Time Perspective: Retrospective|
|Official Title:||Myocardial Infarction as the First Manifestation of Coronary Heart Disease: Rates of Heralded and Unheralded Myocardial Infarction. A CALIBER Study|
- First myocardial infarction (MI) [ Time Frame: Average time frame: patients in the GPRD are followed from registration until they experience the outcome, leave the practice, die, or 31st December 2009, whichever occurs first. ] [ Designated as safety issue: No ]
First MIs will be divided into three groups:
(i) Those with previous manifestations of cardiovascular disease, diagnosed or treated more than 90 days before the MI. These are the 'Heralded MIs'.
(ii) Those with a diagnosis or treatment of cardiovascular disease occurring only within 90 days before MI. These are the 'MIs with premonitory symptoms'.
(iii) Those without any previous manifestation of cardiovascular disease at any time before MI. These are the 'Unheralded MIs'.
|Study Start Date:||September 2009|
|Estimated Study Completion Date:||December 2014|
|Estimated Primary Completion Date:||December 2013 (Final data collection date for primary outcome measure)|
All patients included in "up to standard" GPRD practices that agreed to the linkage with the MINAP database are included in this cohort.
This study is part of the CALIBER (Cardiovascular disease research using linked bespoke studies and electronic records) programme funded over 5 years from the NIHR and Wellcome Trust. The central theme of the CALIBER research is linkage of the Myocardial Ischaemia National Audit Project (MINAP) with primary care (GPRD) and other resources. The overarching aim of CALIBER is to better understand the aetiology and prognosis of specific coronary phenotypes across a range of causal domains, particularly where electronic records provide a contribution beyond traditional studies. CALIBER has received both Ethics approval (ref 09/H0810/16) and ECC approval (ref ECC 2-06(b)/2009 CALIBER dataset).
Using data from MINAP and GPRD, patients experiencing their first myocardial infarction (MI) will be separated into three categories:
- 'Heralded MI': patients who have been diagnosed or treated for cardiovascular disease for more than 90 days before MI.
- 'MI with premonitory symptoms': patients who have been diagnosed or treated for cardiovascular disease within the 90 days prior to MI.
- 'Unheralded MI': patients without a cardiovascular disease diagnosis or treatment at any time before MI.
Patients with MI will be identified in the linked GPRD-MINAP record. Using GPRD population denominators, this study will establish the absolute incidence rates of first 'unheralded' MI by calendar year, age, sex, season, MI subtype (ST-elevation MI and non ST-elevation MI) and region and compare these to the rates of first 'heralded' MIs and first 'MI with premonitory symptoms'.
|London School of Hygiene and Tropical Medicine|
|London, United Kingdom, WC1E 7HT|
|Principal Investigator:||Emily Herrett, MSc||London School of Hygiene and Tropical Medicine|
|Study Director:||Harry Hemingway, FRCP||University College, London|