TABLE 3.
Hazard ratios for risk of coronary heart disease according to visit-to-visit HbA1c variability
| Quartile 1 | Quartile 2 | Quartile 3 | Quartile 4 | P for trend | Per 1-unit increasea | |
|---|---|---|---|---|---|---|
| HbA1c SD | ||||||
| No. of patients | 6768 | 7406 | 7517 | 7569 | ||
| No. of cases | 399 | 651 | 672 | 626 | ||
| Person-years | 24 108 | 27 633 | 28 357 | 27 019 | ||
| Age, sex and race, adjusted HR (95% CI) | 1.00 | 1.39 (1.23–1.57) | 1.46 (1.29–1.66) | 1.71 (1.50–1.94) | <.001 | 1.30 (1.24–1.37) |
| Model 1, HR (95% CI)b | 1.00 | 1.32 (1.16–1.50) | 1.32(1.15–1.51) | 1.52 (1.32–1.74) | <.001 | 1.16(1.08–1.25) |
| Model 2, HR (95% CI)c | 1.00 | 1.31 (1.14–1.49) | 1.40 (1.22–1.60) | 1.71 (1.46–2.01) | <.001 | 1.27(1.15–1.37) |
| HbA1c CV | ||||||
| No. of patients | 6851 | 7388 | 7488 | 7533 | ||
| No. of cases | 394 | 637 | 681 | 636 | ||
| Person-years | 24 429 | 27 672 | 28 212 | 26 804 | ||
| Age, sex and race, adjusted HR (95% CI) | 1.00 | 1.40 (1.23–1.59) | 1.54 (1.36–1.74) | 1.77(1.55–2.01) | <.001 | 1.27 (1.20–1.35) |
| Model 1, HR (95% CI)b | 1.00 | 1.31 (1.15–1.50) | 1.41 (1.23–1.60) | 1.55 (1.35–1.79) | <.001 | 1.15 (1.08–1.22) |
| Model 2, HR (95% CI)c | 1.00 | 1.30 (1.14–1.49) | 1.46 (1.28–1.66) | 1.65 (1.42–1.90) | <.001 | 1.20(1.12–1.29) |
| Adjusted HbA1c SD | ||||||
| No. of patients | 6641 | 7414 | 7560 | 7645 | ||
| No. of cases | 375 | 656 | 667 | 650 | ||
| Person-years | 23 366 | 27 597 | 28 589 | 27 566 | ||
| Age, sex and race, adjusted HR (95% CI) | 1.00 | 1.45 (1.27–1.64) | 1.48 (1.30–1.68) | 1.77 (1.55–2.01) | <.001 | 1.32 (1.23–1.42) |
| Model 1, HR (95% CI)b | 1.00 | 1.34 (1.17–1.54) | 1.30(1.12–1.50) | 1.58(1.36–1.81) | <.001 | 1.20 (1.10–1.30) |
| Model 2, HR (95% CI)c | 1.00 | 1.40 (1.23–1.60) | 1.42 (1.22–1.61) | 1.71 (1.46–2.03) | <.001 | 1.32 (1.21–1.45) |
Abbreviations: CI, confidence interval; CV, coefficient of variation; SD, standard deviation.
a
Per 10 unit increase for HbA1c CV.
b
Model 1 adjusted for age, race, sex, smoking, body mass index, systolic blood pressure, non-HDL/HDL ratio, estimated glomerular filtration rate, insurance type, hypoglycaemia events, glucose-lowering medications, antihypertensive medications, lipid-lowering medications and antiplatelet and anticoagulant medications by category differences.
c
Model 2 adjusted for covariates in model 1 plus the updated mean value of HbA1c.