Exploring Geographic Heterogeneity in Anemia-Associated Outcomes Across Indian Intensive Care Units

Introduction: Severe anemia is common in critically ill patients, potentially highlighting health inequities in low- and middle-income countries like India, where cities are tiered by infrastructure and economy. We hypothesize that risk factors and ICU outcomes vary by city tier, and severe anemia adversely impacts outcomes, with tier-specific variations.


Methods: This multi-center analysis utilized data from a proprietary tele-ICU platform (Jan 2022- Jan 2025), encompassing 29,919 admissions across 260 ICUs in 179 cities from 22 Indian states. Severe anemia (N=2908) was defined as hemoglobin (Hgb) less than 7 g/dL at ICU presentation. Cities were categorized into Tier1 (N=4373), 2 (N=9841), or 3 (N=15705). Kruskal-Wallis, Dunn, Chi-square, and pair-wise proportion tests were used to compare risk factors and outcomes across tiers. Logistic and linear regressions were used for associations between anemia and outcomes


Results: Severe anemia increased the odds of adverse clinical outcomes, with disparities more pronounced in Tier2 and 3 cities. Risk factors (age, initial Hgb value, severe anemia, microcytic anemia) and outcomes (APACHE II score, length of stay, total days on ventilator, mortality) varied significantly by tier (p < 0.001), while gender and pressor use did not.Severe anemia increased mortality odds (OR 1.72 [1.53 – 1.93]). Among severely anemic patients, those in Tier3 had higher mortality odds compared to Tier2 (OR 1.78, p< 0.001). Severe anemia also increased the odds of being placed on pressors (OR 1.48 [1.18 – 1.83]), with no significant differences between tiers. Patients with severe anemia had an APACHE II score that was on average 4.37 points higher (p < 0.001) than those without. Among severely anemic patients, those in Tier2 (1.62 points, p< 0.01) and Tier3 (1.46 points, p< 0.01) had significantly higher APACHE scores than Tier1. No statistically significant difference in length of stay or total ventilator days was found between anemic and non-anemic groups.


Conclusions: Severe anemia correlates with worse clinical outcomes in critically ill Indian patients, including increased mortality, higher APACHE II scores, and greater need for pressor support. These risks are exacerbated in patients from Tier2 and 3 cities, suggesting that geographic disparities amplify the burden of severe anemia.