Background: Outpatient parenteral antimicrobial therapy (OPAT) is common among patients requiring intravenous antibiotics beyond hospitalization. However, OPAT is associated with catheter-related adverse events (AEs), which occur more frequently than drug-related AEs and may lead to care interruptions or harm. We compared AEs related to the most common venous catheters used for OPAT: midline catheters (midlines) and peripherally inserted central catheters (PICCs).
Methods: The Michigan Hospital Medicine Safety (HMS) consortium collects patient-level demographic and clinical data on a sample of midline and PICC placements on medical patients admitted in 69 participating hospitals. We analyzed data from catheters placed from February 2017 through April 2023 on hospitalized patients who were transitioned to OPAT upon discharge. Patients were followed until catheter removal, death, or 30 days from catheter placement, whichever came first. The primary outcome of interest was the composite of catheter-related AEs: occlusion, bloodstream infection (BSI), and venous thromboembolism (VTE, including upper extremity deep venous thrombosis and pulmonary embolism). We evaluated the association between the type of catheter (midline vs. PICC) and primary outcome using Cox proportional hazards model to account for variation in catheter dwell time while adjusting for age, sex, Charlson comorbidity score, history of VTE, history of central line-associated bloodstream infection, active malignancy, presence of another central vein catheter, catheter lumens, and catheter size.
Results: Of 5,337 catheters used for OPAT, 2,496 (47%) were midlines and 2,839 (53%) were PICCs. Patients with midlines were older compared to those with PICCs (median, 66.8 vs 64.0 years, p < 0.001); otherwise, both groups were similar in terms of body mass index, Charlson score, and place of residence (Table 1). Catheters < 5Fr in size were used for all midlines and for 84% of PICCs. Single-lumen catheters accounted for 97.8% of midlines vs. 88.7% of PICCs (p < 0.001). Midlines were used for shorter durations compared to PICCs (median, 11 vs. 20 days, p < 0.001). Taking catheter dwell into account and after adjusting for patient and device factors, a lower hazard of the composite of catheter-related adverse events was observed in patients with midlines compared to those with PICCs (Hazard Ratio [HR], 0.68; 95% confidence interval [CI], 0.51-0.90) (Table 2).
Conclusions: When used for outpatient parenteral antimicrobial therapy, midlines are associated with a lower risk of catheter-related adverse events compared to PICCs. Since antimicrobials vary in physicochemical characteristics, future studies are necessary to evaluate the risk of adverse events from specific treatments.
