Table 2. Discrimination and Calibration of the Pooled Cohort Equations Across Body Mass Index Categories.
| BMI category | C statistic (95% CI) | Mean E/O RRa (95% CI) | ||||
|---|---|---|---|---|---|---|
| All cohorts | Derivation cohort studiesb | Nonderivation cohort studiesc | All cohorts | Derivation cohort studiesb | Nonderivation cohort studiesc | |
| Total | 0.760 (0.753-0.767) | 0.758 (0.746-0.770) | 0.761 (0.752-0.770) | 1.22 (1.18-1.26) | 0.97 (0.92-1.02) | 1.32 (1.28-1.36) |
| Underweight (<18.5) | 0.789 (0.731-0.848) | 0.777 (0.651-0.903) | 0.793 (0.727-0.859) | 1.01 (0.79-1.35) | 0.69 (0.41-1.58) | 1.09 (0.84-1.55) |
| Normal weight (18.5 to <25) | 0.785 (0.772-0.798) | 0.777 (0.755-0.799) | 0.792 (0.777-0.807) | 1.21 (1.14-1.28) | 0.87 (0.79-0.96) | 1.36 (1.27-1.45) |
| Overweight (25 to <30) | 0.759 (0.748-0.770) | 0.758 (0.739-0.777) | 0.759 (0.745-0.773) | 1.17 (1.12-1.22) | 0.94 (0.87-1.01) | 1.28 (1.21-1.35) |
| Mild obesity (30 to <35) | 0.738 (0.722-0.755) | 0.744 (0.718-0.770) | 0.734 (0.713-0.755) | 1.24 (1.17-1.32) | 1.03 (0.93-1.16) | 1.32 (1.21-1.43) |
| Moderate to severe obesity (≥35) | 0.742 (0.721-0.763) | 0.737 (0.697-0.777) | 0.739 (0.715-0.764) | 1.36 (1.25-1.47) | 1.23 (1.03-1.47) | 1.38 (1.26-1.51) |
Abbreviations: BMI, body mass index (calculated as weight in kilograms divided by height in meters squared); E/O RR, expected-to-observed risk ratio.
a
An RR of 1 indicates perfect calibration across the full spectrum of risk; greater than 1, overestimation of risk; and less than 1, underestimation of risk.
b
Atherosclerosis Risk in Communities, Coronary Artery Risk Development in Young Adults, and Cardiovascular Health Study.
c
Dallas Heart Study, Framingham Heart Study Third Generation, Jackson Heart Study, Multi-Ethnic Study of Atherosclerosis, and Reasons for Geographic and Racial Differences in Stroke.