The three peaks in age distribution of females with pneumothorax: a nationwide database study in Japan.

Abstract

Women are the minority among patients with spontaneous pneumothorax, but catamenial pneumothorax (CP) is unique to them. We aimed to clarify the clinical characteristics of female patients with spontaneous pneumothorax using a nationwide database. Medical records from the Japanese Diagnosis Procedure Combination database for inpatients with pneumothorax between July 2010 and March 2016 were retrospectively reviewed. Age, underlying diseases, body mass index, smoking status, laterality, number of hospitalizations and treatments were studied. We identified 157 087 patients with pneumothorax, including 27 716 (17.6%) women and 129 371 (82.4%) men. The age distribution of female patients with pneumothorax had 3 peaks: 18 years, around 40 years and 80 years; male patients had 2 peaks: 18 years and 79 years. We identified 873 patients with CP; this number was not sufficient to account for the female-specific peak around 40 years. The characteristics of female patients of reproductive age were significantly different between those with and without CP. The patients with CP were older (average age: 37.9 ± 7.7 years vs 31.3 ± 11.5 years, P < 0.001), were right side dominant (right: 64.9%, left: 6.5%), had more hospitalizations (average number of hospitalizations: 1.6 ± 0.9 vs 1.3 ± 0.6, P < 0.001) and had more frequently undergone surgery (57.1% vs 37.3%, P < 0.001). The age distribution of women with pneumothorax had 3 distinct peaks while that of men had 2. CP has different characteristics from other types of pneumothorax, thus requiring different treatment strategies for women of reproductive age.