Factors related to primary bilateral spontaneous pneumothorax.

Objectives: We studied the risk factors associated with primary bilateral spontaneous pneumothorax. Methods: From January 2001 to December 2002, 102 patients with primary spontaneous pneumothorax were reviewed and divided into two groups. Group A patients had primary spontaneous bilateral pneumothorax (PSBP; simultaneous or nonsimultaneous). Group B included patients with a primary spontaneous pneumothorax (PSP). We compared age, smoking habits, body weight, height, body mass index (BMI), and radiological findings between groups. Results: Twenty-four patients developed PSBP (24%). The male-to-female ratio was 22:2 in group A and 73:5 in group B (p=0.106). Eleven group A patients (46%) and 34 group B patients (44%) were smokers (p=0.037). The mean BMI was 18.39 +/- 2.45 kg/m(2) in group A and 19.70 +/- 2.00 kg/m(2) in group B (p = 0.009). High-resolution computed tomography revealed bilateral lung blebs or bullae in 63% of group A patients and in 53% of group B patients (p = 0.724). Conclusion: PSBP was significantly more frequent in patients with a lower BMI and among smokers. These patients require extended hospitalization and vigilant treatment.