Considerable differences exist between prevalent and incident myocardial infarction cohorts derived from the same
Brian S Buckley1, Colin R Simpson, David J McLernon
1Department of General Practice, Clinical Sciences Institute, National University of Ireland, Galway, Ireland. briansbuckley@gmail.com
Insights
Prevalent and incident cohorts for ischemic heart disease (IHD) show significant differences in patient characteristics and survival outcomes. Incident cohorts from the general population are recommended for accurate survival estimations in IHD research.
Area of Science:
- Cardiovascular Epidemiology
- Clinical Prognostics
Background:
- Epidemiological studies of ischemic heart disease (IHD) utilize both prevalent and incident cohorts.
- Understanding the distinctions between these cohort types is crucial for accurate data interpretation.
Purpose of the Study:
- To compare baseline characteristics and prognostic outcomes between prevalent and incident cohorts of acute myocardial infarction (AMI).
- To determine the most suitable cohort type for reliable survival estimations in IHD research.
Main Methods:
- Linked primary care, secondary care, and death certification data were used to identify prevalent and incident AMI cohorts from a single population.
- Cohorts were independently analyzed for baseline demographics, survival rates (all-cause and IHD-specific), revascularization procedures, and subsequent AMIs.
Main Results:
- Prevalent cohort members were older (mean age 71.0 vs. 64.7 years) and had higher 5-year mortality rates from any cause (31.4% vs. 18.0%) and IHD (18.5% vs. 12.2%) compared to incident cases.
- Mean time to death was shorter in the prevalent cohort, while the incident cohort experienced shorter mean time to a subsequent AMI.
- Fewer prevalent cases underwent coronary artery bypass grafting or percutaneous transluminal coronary angioplasty.
Conclusions:
- Significant disparities exist in baseline characteristics and prognosis between prevalent and incident IHD cohorts.
- Incident cohorts, particularly those derived from the general population, offer more reliable data for estimating survival in ischemic heart disease.
Objective:
Both prevalent and incident cohorts have been used in epidemiological and prognostic studies of ischemic heart disease (IHD). This study considers the differences between the cohort types.
Study Design And Setting:
Using linked primary care, secondary care, and death certification data, prevalent and incident cohorts of people with a first acute myocardial infarction (AMI) were formed from the same population. They were analyzed independently in terms of baseline characteristics and survival to revascularization, another AMI, or death.
Results:
55.7% of the prevalent cohort members were males, with a mean age of 71.0 years (standard deviation [SD]: 12.0). 59.0% of the incident cohort members were males, with a mean age of 64.7 years (SD: 13.3). Over 5 years, a greater proportion of prevalent cases died from any cause (31.4% [95% confidence interval(CI): 28.6-34.3]) and IHD (18.5% [95% CI: 16.2-21.0]) than incident cases (18.0% [95% CI: 15.0-21.4] and 12.2% [95% CI: 9.7-15.2], respectively). Mean time to death was shorter in prevalent cases. There was a small difference in the numbers of subsequent AMIs between cohorts. In the incident cohort, mean time to AMI was shorter. Fewer prevalent cases underwent coronary artery bypass grafting or percutaneous transluminal coronary angioplasty.
Conclusion:
Considerable differences existed between the two cohorts in terms of baseline characteristics and prognosis. Incident cohorts derived from whole populations should be sought for estimation of survival.
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