Table 1.
Baseline characteristics of the full cohort, stratified by hemoglobin groups.
Table 2.
Index admission interventions and discharge medications in the full cohort, stratified by hemoglobin group.
Fig 1.
Covariate balance before and after adjustment.
Standardized mean differences (SMDs) are shown for each covariate in the original unmatched cohort (blue circles), after Mahalanobis distance matching (MDM; green squares), and after entropy balancing (EBAL; orange triangles). Vertical dashed lines mark SMD thresholds of 0.1 (red) and 0.2 (orange). CKD, chronic kidney disease; COPD, chronic obstructive pulmonary disease; AF, atrial fibrillation; IHD, ischemic heart disease; PVD, peripheral vascular disease; HTN, hypertension.
Table 3.
Clinical outcomes in the matched cohort (Mahalanobis distance matching, 3:3:1), stratified by hemoglobin group.
Fig 2.
Kaplan–Meier survival curves for patients in the matched cohort (Mahalanobis distance matching, 3:3:1), stratified by hemoglobin group.
The overall log-rank test showed a significant difference between groups (p = 0.027). In Cox proportional hazards analysis (reference = normocythemia), anemia was associated with higher mortality (HR 1.30, 95% CI 1.03–1.63, p = 0.026), whereas polycythemia was not (HR 0.90, 95% CI 0.64–1.27, p = 0.533). Post-hoc pairwise log-rank tests with Bonferroni correction were not statistically significant (anemia vs. normocythemia p = 0.073; anemia vs. polycythemia p = 0.109; normocythemia vs. polycythemia p = 1.000). Numbers at risk are displayed below the x-axis.
Fig 3.
Kaplan–Meier survival curves from the sensitivity analysis using entropy balancing (EBAL), stratified by hemoglobin group.
The overall weighted log-rank test was significant (p < 0.001). In weighted Cox proportional hazards analysis (reference = normocythemia), anemia was associated with higher mortality (HR 1.76, 95% CI 1.61–1.92, p < 0.001), whereas polycythemia was not (HR 1.14, 95% CI 0.83–1.57, p = 0.410). Post-hoc weighted log-rank tests with Bonferroni correction showed significant differences between anemia and normocythemia (p < 0.001) and between anemia and polycythemia (p = 0.015), but not between normocythemia and polycythemia (p = 0.931). Numbers at risk are not displayed because weighting alters group counts.