Clinical-epidemiological predictors of phlebitis associated with peripheral intravenous catheters in Spanish hospitals: results of a national cohort study.

Background: Peripheral intravenous catheters (PIVC) are essential medical devices, yet they frequently lead to complications such as phlebitis, infiltration, and occlusion. Identifying risk factors is key to reducing these complications. Objectives: To estimate the incidence of PIVC‑associated phlebitis in Spanish hospitals and identify clinical and epidemiological risk factors. Methods: We performed a prospective cohort study in 80 Spanish hospitals from 1 to 28 February 2023. Adult inpatients (≥18 years) receiving PIVCs in non‑ICU, non‑emergency, non‑pediatric wards were eligible. A total of 13,812 PIVCs in 9387 patients were followed daily by trained nurses until catheter removal, phlebitis onset (Maddox grade ≥ 2), or 15 days. We calculated cumulative incidence and incidence density per 100 catheter‑days. Multivariable Cox proportional hazards models estimated hazard ratios (HRs) for predictors-sex, age group, number of infused medications, hospital size, and dwell time. Results: Phlebitis occurred in 1302 PIVCs (cumulative incidence 9.43 %; incidence density 0.14 per 100 person‑hours). Independent risk factors were female sex (HR 1.32, 95 % CI 1.21-1.45), age 65-79 years (HR 1.25, 95 % CI 1.12-1.40), administration of ≥ 2 medications (HR 1.50, 95 % CI 1.35-1.67), and hospital size ≥ 1000 beds (HR 1.30, 95 % CI 1.12-1.52). Phlebitis risk peaked 48-96 h post‑insertion. Conclusions: Phlebitis incidence remains above recommended levels. Multivariable analysis identified female sex, a higher number of infused medications, older patient age, larger hospital size, and longer PIVC dwell time as the main independent predictors of phlebitis.