Re-calibration methods
| Background info: Re-calibration methods |
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| It is inevitable that a scale degenerated from one population will predict inaccurately when applied directly to an ethnically distinct group of people (e.g. Caucasians and Asians) |
| However, it will be financially draining if a separate scale were to be degenerated for each individual type of population |
| To combat this problem, methods of recalibration were devised to substitute baseline values of a new population into the formula of a scale. Theoretically, this will improve the predictive ability of the calibrated-scale given that the relationship between the risk factors and the disease measured is constant in all the different populations. |
- From the authors of Framingham
- With recalibration, the Framingham mean values of the risk factors are replaced by the mean values of the risk factors from a non-Framingham cohort, while the Framingham average incidence rate is replaced by the cohort’s own average incidence rate.
- Recalibration does not affect relative risk comparisons or discrimination evaluations.
(D’Agostino RB, Sr, Grundy S, Sullivan LM, Wilson P. Validation of the Framingham coronary heart disease prediction scores: results of a multiple ethnic groups investigation. JAMA. 2001;286:180-187. http://www.ncbi.nlm.nih.gov/pubmed/11448281)
- Asia pacific population study
- Substitution of the Framingham baseline survival at 8 years (the complement of the average incidence rate of cardiovascular disease) and mean vales (or prevalence) of the risk factors from the target population
(Barzi F, Patel A, Gu D, Sritara P, Lam TH, Rodgers A, Woodward M. Cardiovascular risk prediction tools for populations in Asia. Journal of Epidemiology and Community Health 2007; 61: 115-121.)
- Substitution of the Framingham baseline survival at 8 years (the complement of the average incidence rate of cardiovascular disease) and mean vales (or prevalence) of the risk factors from the target population
- Framingham-RECIGOR (Spain)
- The recalibration procedure consists of replacing the Framingham means of the risk factors and the average event rate by those of the target population, under the assumption that the effects of the risk factors are reasonably universal.
(Marrugat J, D’Agostino R, Sullivan L, Elosúa R, Wilson P, Ordovás J, Solanas P, Cordón F, Ramos R, Sala J, et al.: An adaptation of the Framingham coronary heart disease risk function to European Mediterranean areas. J Epidemiol Community Health 2003, 57:634-638)
- The recalibration procedure consists of replacing the Framingham means of the risk factors and the average event rate by those of the target population, under the assumption that the effects of the risk factors are reasonably universal.