Table 4 -.
Associations between preoperative anemia status and outcomes according to sex
|
Males |
Females |
|||||||
|---|---|---|---|---|---|---|---|---|
| Moderate/severe§ | Mild§ | Moderate/severe§ | Mild§ | |||||
| Outcome | Estimate (95% CI) | p | Estimate (95% CI) | p | Estimate (95% CI) | p | Estimate (95% CI) | p |
| Acute kidney injury | 1.75 (0.95 to 3.23) | 0.073 | 1.45 (1.11 to 1.88) | 0.006 | 4.50 (2.17 to 9.31) | <.001 | 2.64 (1.63 to 4.27) | <.001 |
| Any perioperative RBCs‡ | - | - | 5.15 (4.16 to 6.37) | <.001 | 11.57 (4.10 to 32.64) | <.001 | 7.30 (5.10 to 10.45) | <.001 |
| Return to OR | 0.90 (0.47 to 1.70) | 0.736 | 0.94 (0.73 to 1.21) | 0.639 | 1.29 (0.69 to 2.42) | 0.431 | 1.53 (1.13 to 2.05) | 0.005 |
| Vascular complications | 1.46 (0.55 to 3.89) | 0.444 | 1.26 (0.81 to 1.95) | 0.302 | 0.90 (0.20 to 4.00) | 0.886 | 1.15 (0.60 to 2.20) | 0.672 |
| Hospital length of stay** | 1.34 (1.23 to 1.46) | <.001 | 1.08 (1.05 to 1.11) | <.001 | 1.28 (1.19 to 1.39) | <.001 | 1.04 (1.00 to 1.07) | 0.058 |
Results are from multivariable linear or logistic regression models. Estimates are odds ratios unless noted and reflect the sex-specific increase in odds associated with the given anemia category relative to patients without anemia. Moderate/severe anemia defined by hemoglobin <10 g/dL. Mild anemia defined by hemoglobin 10–12 g/dL (female) and 10–13 g/dL (males). For each outcome, a model was fit with covariates, categorical pre-operative anemia variable, and the sex by categorical pre-operative anemia interaction term. Covariables included type of surgery (valve vs. CABG), age, sex, BMI, smoking history, history of moderate to severe kidney disease, MI, stroke, diabetes, preoperative creatinine and platelet count, and cardio-pulmonary bypass duration.
To test whether the effect of WHO anemia category differed according to sex, the sex by WHO anemia category interaction term was assessed for each model. The two degree of freedom p-values associated with the interaction term were 0.032, 0.249, 0.040, 0.851, and <.001 for outcomes Acute kidney injury, Any perioperative RBCs, Return to OR, Vascular complications, and Hospital length of stay, respectively.
Effect of moderate/severe anemia is not estimable. All men classified as moderate to severely anemic required perioperative RBCs.
Estimates reflect the sex-specific multiplicative increase in geometric mean associated with the given anemia category relative to patients without anemia.