Surgical repair of paraesophageal hernia resolves unexplained iron deficiency anemia in the vast majority of patients: a propensity-matched multicenter study

BACKGROUND: Paraesophageal hernias (PEH) frequently associate with iron deficiency anemia (IDA) through unclear mechanisms. We investigated whether surgical repair effectively treats unexplained IDA in patients with PEH. METHODS: This multicenter retrospective study (2010-2024) analyzed 1700 patients undergoing hiatal hernia repair across Asuta Medical Centers. After excluding patients with identifiable bleeding sources (Cameron lesions, erosive gastritis, ulcers), 522 patients remained: 136 with unexplained IDA and 386 controls. Propensity score matching (1:3) aligned 99 anemic patients with 297 controls based on age, sex, BMI, and comorbidities. Primary endpoint was anemia resolution at 12 months (hemoglobin > 12 g/dL females, > 13 g/dL males without iron supplementation). RESULTS: Baseline hemoglobin was 10.5 ± 1.4 vs 13.9 ± 1.2 g/dL (p < 0.001). Anemia severity was mild (62.6%), moderate (31.3%), or severe (6.1%). Despite profound anemia, 42.4% were completely asymptomatic at presentation. Prior iron therapy had failed in 78.2% over 5.8 ± 3.2 months. Anemia resolution occurred in 93.4% (92/99) at 12 months, with 88.9% achieving normal hemoglobin by 3 months. Mean hemoglobin increased by 3.2 g/dL (95% CI 2.9-3.5, p < 0.001), with ferritin normalizing from 19.3 ± 11.8 to 95.3 ± 38.5 ng/mL. Iron supplementation was successfully discontinued in 82.8% of patients. Among 16 patients with hernia recurrence, 75% maintained normal hemoglobin despite anatomical failure. Control group hemoglobin remained unchanged (13.9 ± 1.2 to 13.9 ± 1.1 g/dL, p = 0.892). Due to only 7 non-resolution events, multivariate analysis was not performed; however, diabetes (71.4% vs. 28.3%) and chronic kidney disease (28.6% vs. 3.3%) were associated with persistent anemia. CONCLUSIONS: Unexplained IDA resolves in > 90% of patients following PEH repair, with durable results often maintained despite anatomical recurrence. These findings suggest PEH repair should be considered for patients with unexplained, refractory IDA. Prospective studies are needed to establish evidence-based criteria for this underrecognized indication.