Predictors of Severity in Adverse Reactions to Subcutaneous Medications: A Nationwide Pharmacovigilance Study in...

Adverse drug events (ADEs) associated with subcutaneous (SC) medication use represent an escalating public health concern. However, data regarding the severity and associated risk factors of these events in Brazil remain limited, which impedes the development of effective safety interventions. This study aimed to characterize ADE reports linked to SC drug administration in Brazil from 2019 to 2024 and to identify sociodemographic and clinical predictors of severity.

A cross-sectional analysis was conducted utilizing 4954 ADE reports from the Brazilian VigiMed pharmacovigilance database. The variables assessed included patient demographics, reporter type, drug class, and event severity (eg, hospitalization, death). Associations were evaluated using χ 2 tests, and multivariate logistic regression was used to identify independent predictors of severity.

The majority of reports involved female patients (69.2%) and individuals aged 60 years or older (54.9%). Endocrine and metabolic agents were the most frequently implicated drug class (54.4%). Severe ADEs accounted for approximately one-third of all reports, with hospitalization (27.3%) and death (8.3%) being the most common outcomes. After adjustment, male sex [adjusted odds ratio (aOR) 1.31], age ≥60 years (aOR 1.48), reports from health care services (aOR 3.80), and nonspontaneous notifications (eg, clinical studies; aOR 1.52) were significantly associated with increased severity.

Subcutaneous medications in Brazil are associated with a considerable burden of severe ADEs, particularly among older adults and male patients. Strengthening pharmacovigilance systems, enhancing professional training, and implementing robust safety protocols are essential measures to mitigate harm and ensure safer SC drug administration.