Retrospective case-control analysis of the infectious complications of retained broken needles in people who inject drugs.

Retained broken needles (RBNs) in patients is a potentially underreported complication of intravenous drug use (IVDU) in people who inject drugs. Identification of RBNs poses a challenge for radiologists and clinicians due to subtle appearance on imaging and the complexities of patient presentations. A single-center case-control study was performed between January 1, 2021, and December 31, 2021. The cases included all patients with a history of IVDU who presented to the emergency department (ED) with RBNs. Data collected on the study population included RBN location and size, complications, and imaging modality. A control group of 2:1 matched on age, gender, and race/ethnicity with the cases was generated from patients with a history of IVDU from the same time period who had no RBNs. A total of 3920 total patients presented to ED with a history of IVDU and 70 patients were found to have RBN (1.8%). RBNs were most observed in the foot/ankle (32.9%) forearm (18.6%), and neck (17.1%). RBNs were found to be incidental in 82.9% (58 out of 70) of patients. Radiography located needle fragments (55.7%) slightly more often than CT (44.3%). Overall, among all the cases and controls combined, 33.8% had positive blood cultures. In the group of patients with a RBN, 47.1% presented with positive bacterial blood cultures during the hospital admission, whereas the group without an RBN showed 27.1% (P = .004). The RBN group showed significantly higher rates of abscess (72.9% vs 48.6%), cellulitis (70.0% vs 46.4%), and osteomyelitis (37.1% vs 13.6%) than the non-RBN group (all P ≤ .001). This study suggests that RBNs are likely underreported and patients with RBNs are at an increased risk of infectious complications. Increasing the awareness and refining our understanding of RBNs is crucial to mitigating these complications.