Association Between BMI and Recurrence of Primary Spontaneous Pneumothorax

Background Whether body mass index (BMI) is a significant risk factor for recurrence of primary spontaneous pneumothorax (PSP) remains controversial. The purpose of this study was to examine whether BMI and other factors are linked to risk of PSP recurrence. Methods A consecutive cohort of 273 patients was retrospectively evaluated. Patients were divided into those who experienced recurrence (n = 81) and those who did not (n = 192), as well as into those who had low BMI (n = 75) and those who had normal or elevated BMI (n = 198). The two pairs of groups were compared in terms of baseline data, and Cox proportional hazards modeling was used to identify predictors of PSP recurrence. Results Rates of recurrence among all 273 patients were 20.9% at 1 year, 23.8% at 2 years, and 28.7% at 5 years. Univariate analysis identified the following significant predictors of PSP recurrence: height, weight, BMI, size of pneumothorax, and treatment modality. Multivariate analyses identified several risk factors for PSP recurrence: low BMI, pneumothorax size >= 50%, and non-surgical treatment. Kaplan-Meier survival analysis indicated that patients with low BMI showed significantly lower recurrence-free survival than patients with normal or elevated BMI (P < 0.001). Conclusions Low BMI, pneumothorax size >= 50%, and non-surgical treatment were risk factors for PSP recurrence in our cohort. Low BMI may be a clinically useful predictor of PSP recurrence.