Severe anemia and red cell product ordering burden among women hospitalized with benign uterine disorders: a retrospective cohort study using MIMIC-IV.

Abstract

Background: Benign uterine disorders, including uterine leiomyomas and uterine endometriosis/adenomyosis-related conditions, are common causes of gynecologic morbidity and represent an important women's health issue. Although these conditions are generally non-malignant, a subset of hospitalizations may involve substantial anemia-related clinical burden. Evidence describing severe inpatient anemia, red cell product ordering, intensive care unit (ICU) use, and short-term hospital outcomes in this population remains limited.

Methods: We conducted a retrospective cohort study using hospital data from the Medical Information Mart for Intensive Care IV (MIMIC-IV). Adult female hospitalizations with diagnostic codes related to benign uterine disorders were identified. Hospitalizations with missing hemoglobin data, pregnancy- or obstetric-related diagnoses, and gynecologic malignancy-related diagnoses were excluded. The unit of analysis was hospitalization. Severe anemia was defined as a minimum inpatient hemoglobin level < 8 g/dL during hospitalization. The main outcome was red cell product ordering identified from Blood Bank provider order entry records, which was interpreted as a transfusion-related resource use indicator rather than confirmed red cell administration. Additional hospital burden outcomes included hospital length of stay, ICU admission during hospitalization, in-hospital mortality, and gynecologic procedure-related outcomes. Multivariable logistic regression was used to evaluate the association of severe anemia with red cell product ordering and ICU admission. Models were adjusted for age, race/ethnicity, insurance status, marital status, admission type, and disease group. Sensitivity analyses used hemoglobin < 10 g/dL as an alternative anemia threshold.

Results: The final cohort included 1,860 non-obstetric, non-malignant hospitalizations with available hemoglobin data. Severe anemia was present in 425 hospitalizations (22.8%). Compared with hospitalizations without severe anemia, those with severe anemia had a higher proportion of red cell product orders (63.29% vs. 5.09%), longer hospital length of stay [3.436 (1.911-6.389) vs. 2.310 (1.335-3.816) days], and more frequent ICU admission during hospitalization (15.06% vs. 6.13%). In-hospital mortality was uncommon overall and was analyzed only exploratorily. After multivariable adjustment, severe anemia was associated with red cell product ordering [adjusted odds ratio (OR) 33.61, 95% confidence interval (CI) 24.23-47.29] and ICU admission during hospitalization (adjusted OR 2.69, 95% CI 1.84-3.91). In the fibroid-only subgroup, the corresponding adjusted ORs were 35.55 (95% CI 24.96-50.64) for red cell product ordering and 2.68 (95% CI 1.83-3.92) for ICU admission. Sensitivity analyses using hemoglobin < 10 g/dL showed directionally consistent findings. Additional sensitivity analyses using earlier hemoglobin definitions showed that early 24-hour Hb < 8 g/dL remained strongly associated with red cell product ordering (adjusted OR 22.57, 95% CI 15.54-32.80), whereas the corresponding ICU admission estimate was attenuated and not statistically significant (adjusted OR 1.09, 95% CI 0.66-1.80).

Conclusions: Among women hospitalized with benign uterine disorders, severe inpatient anemia was common and was associated with greater red cell product ordering and higher hospital resource use. These findings suggest that severe inpatient anemia may serve as a practical marker of anemia-related hospital burden in this defined hospitalized population, while ICU-related findings and causal interpretation require caution.