Retained foreign bodies (RFB) after operative interventions are linked to an increased risk of morbidity and mortality, and represent a medico-legal liability. We aimed to identify associated risk factors and outcomes related to iatrogenic RFB in the United States.

A cross-sectional analysis was performed on all interventions that resulted in a secondary diagnosis of RFB in the Nationwide Inpatient Sample (NIS) from 2003 to 2009. Comparative controls were randomly selected from patients who underwent similar procedures.

We identified 3,045 cases of RFB, and 12,592 controls were included. The majority of incidents, 968 (31.8%), were reported after gastrointestinal interventions. Risk of RFB was higher in teaching hospitals (odds ratio [OR] 1.31, 95% CI [1.19, 1.45], p < 0.001). For abdominopelvic procedures, patients admitted with traumatic injuries did not demonstrate a higher risk of RFB compared with electively admitted patients (OR 1.70, 95% CI [0.94, 3.07], p = 0.08). However, for procedures unrelated to abdominopelvic surgery, patients admitted for trauma had a lower risk (OR 0.62, 95% CI [0.50, 0.78], p < 0.001). Obesity (BMI ≥ 30 kg/m²) and older age (≥65 years) were significantly associated with a higher risk only for abdominopelvic procedures (p < 0.01 for both). Retained foreign bodies were associated with a higher average cost of health services ($26,678.00 ± $769.69 vs $12,648.00 ± $192.80, p < 0.001).

Retained foreign bodies have unfavorable and nationally tangible clinical and economic outcomes. The risk profile for RFB at the national level seems to demonstrate an association with demographic and clinical factors including nature of the procedure, type of admission, and trauma status. Teaching hospitals are associated with a higher risk. Targeted efforts toward identified high-risk populations are needed to avoid these morbid and costly complications.