ABO and Rh Blood Group Distributions in Patients With Primary Spontaneous Pneumothorax: A Comparative Population-Based Study Across Two Altitudes

Background First described in the early 19th century as “simple pneumothorax,” primary spontaneous pneumothorax (PSP) refers to the presence of air within the pleural cavity without an identifiable secondary cause. PSP predominantly affects males, smokers, tall individuals, and those with a low body mass index. However, the occurrence of PSP in individuals without these classical risk factors, as well as variability among patients with similar phenotypes, suggests that additional pathophysiological mechanisms may contribute to disease susceptibility. Although ABO and Rh blood group variations have been associated with several pulmonary and systemic diseases, data regarding their relationship with PSP remain limited. Objective This study aimed to evaluate whether ABO and Rh blood group subtypes are associated with PSP by analyzing a homogeneous surgical patient cohort from two cities with distinct altitudes and comparing the findings with national blood group distribution. Methods A total of 174 patients who underwent surgery for PSP between 2021 and 2024 were retrospectively reviewed from two centers located in geographically distinct altitude regions. ABO and Rh distributions were analyzed using Pearson’s chi-square test, inverse probability of treatment weighting (IPTW), and one-sample Z testing. Results Compared with national data, PSP patients showed an overrepresentation of blood group A, an underrepresentation of blood group O, and a lower prevalence of Rh positivity.