The utility of inpatient work-up of incidental anemia during hospitalization for an acute medical condition: A retrospective cohort study.

Introduction: The best timing for evaluation of anemia is not well defined and the clinical yield of performing workup during non-anemia-related hospitalization is unclear. We aimed to evaluate the prognostic value of inpatient laboratory anemia evaluation.

Methods: This was a retrospective propensity-matched cohort study between the years 2013-2022 in Rabin Medical Center Israel. We included all patients admitted for non-anemia-related reasons and were found to be anemic. Patients were divided into groups based on basic laboratory anemia evaluation. Outcomes were cancer diagnosis, colonoscopy rate, duration of admission, and all-cause mortality. Multivariable analysis with competing risk of death was performed and a p-value of 5 % was considered significant.

Results: Following matching, 4,238 patients were included in the evaluation group compared to 7,680 in the no-evaluation group. In-patient laboratory anemia evaluation was associated with gastrointestinal cancer and any cancer diagnosis - HR of 1.53 (95 % CI, 1.15- 2.05) and HR of 1.23 (95 % CI, 1.11-1.37) respectively. The rate of colonoscopy was higher, and anemia prevalence was lower in the evaluation group after 1-year follow-up. Intravenous iron treatment was more prevalent in the evaluation group. The laboratory anemia evaluation prolonged the admission (5 vs 4 days). There was no difference in the all-cause mortality across the 10-year follow-up.

Conclusion: Inpatient anemia evaluation with basic laboratory tests was found to be associated with an increase in outpatient gastrointestinal cancer diagnosis and showed clinical and diagnostic advantages. For patients who can benefit from early gastrointestinal cancer diagnosis, admission holds a valid opportunity to initiate the evaluation.