Clinical factors of prolonged treatment duration in patients with non-puerperal mastitis

Background: Non-puerperal mastitis (NPM) is a benign inflammatory breast disease characterized by a prolonged clinical course and substantial impairment in quality of life. This study aimed to identify clinical factors associated with prolonged treatment duration to support more individualized management strategies.

Methods: This retrospective cohort study included female patients aged 18–60 years with histopathologically confirmed NPM who achieved clinical recovery at a single center between January 2017 and September 2022. Eligible cases were identified through electronic medical records. Exclusion criteria included pregnancy, lactation, malignancy, severe organ dysfunction, and participation in other clinical trials. The primary outcome was treatment duration, measured in months from treatment initiation to documented clinical recovery. Patients were categorized into short-duration (≤6 months) and prolonged-duration (>6 months) groups. Logistic regression and multiple linear regression analyses were performed to evaluate factors associated with prolonged treatment duration.

Results: A total of 121 patients were included in the analysis, with a mean age of 36.5±8.1 years. Among these patients, 74 (61.2%) required more than 6 months to achieve recovery. The median treatment duration was 4.7 months, and 59.5% of patients achieved recovery within 6 months. Multivariate logistic regression identified a maximum breast mass area >50 cm² as an independent factor associated with prolonged treatment duration [odds ratio (OR) =2.70, 95% confidence interval (CI): 1.07–6.78, P=0.04]. Multiple linear regression analysis further demonstrated that larger breast mass area (>50 cm², B=1.98, P=0.02), severe breast pain [numeric rating scale (NRS) ≥5, B=2.00, P=0.02], and abscess formation (B=1.95, P=0.03) were significantly associated with prolonged treatment duration, whereas absence of nipple inversion was associated with shorter recovery duration (B=−1.64, P=0.04).

Conclusions: Larger breast mass area, greater pain severity, nipple inversion, and abscess formation during the lesion stage were identified as potential factors associated with prolonged treatment duration in patients with NPM. Early intervention targeting nipple inversion during the mass stage may reduce the risk of abscess formation and contribute to improved clinical outcomes.