BackgroundReexpansion pulmonary edema (REPE) is known as a rare and fatal complication after tube thoracostomy.ObjectivesWe investigated the risk factors for the development of REPE in patients with spontaneous pneumothorax.MethodsWe selected patients who were diagnosed with spontaneous pneumothorax and were initially treated with tube thoracostomy between August 1, 2003 and December 31, 2011. The patients’ electronic medical records, including operative notes and chest x-ray and computed tomography scans, were reviewed.ResultsREPE developed in 49 of the 306 patients (16.0%). REPE was more common in patients with diabetes (14.3% vs 3.9%, P = 0.004) or tension pneumothorax (46.8% vs 16.2%, P = 0.000). The pneumothorax was larger in patients with REPE than without REPE (57.0 ± 16.0% vs 34.2 ± 17.6%, P = 0.000), and the incidence of REPE increased with the size of pneumothorax. On multivariate analysis, diabetes mellitus [(odds ratio (OR) = 9.93, P = 0.003), and the size of pneumothorax (OR = 1.07, P = 0.000) were independent risk factors of REPE.ConclusionsThe presence of diabetes increases the risk of REPE development in patients with spontaneous pneumothorax. The risk of REPE also increases significantly with the size of pneumothorax.