Retrospective investigation of the incidence of recurrence and risk factors affecting recurrence in patients presenting with primary spontaneous pneumothorax

Introduction and Objective: Primary spontaneous pneumothorax (PSP) is a commonly encountered clinical condition in emergency departments, and its incidence is believed to be on the rise. The risk of PSP recurrence is high, with various studies reporting rates ranging from 20% to 60%. As a result, there are significant variations among the studies in the literature that investigate PSP recurrence rates and the influencing risk factors. In our study, we aimed to ascertain an accurate prediction of PSP recurrence rates and to identify the risk factors associated with recurrence. Materials and Methods: Our study is a retrospective cross-sectional investigation conducted on patients who presented to Dokuz Eylül University Adult Emergency Department between 01.01.2013 and 01.01.2020 with a final diagnosis of first-episode primary spontaneous pneumothorax, following ethical approval. In this study, we examined the short-to-medium-term (within 3 years) recurrence rate of PSP and potential risk factors influencing PSP recurrence. Imaging evaluations of the cases were conducted by a radiology specialist with 17 years of experience. Presence of bullae/blebs, pulmonary dystrophic lesion scores, Light index, and pneumothorax volume measurements were assessed from the patients' imaging by the radiology specialist. Data were analyzed using SPSS version 29. The Mann-Whitney U test was employed to compare medians of numerical data. For comparing categorical data, Pearson's chi-square test and Fischer's exact test were utilized. In the multivariate analysis, potential risk factors were examined using logistic regression analysis. Data were evaluated with a confidence interval of 95%, and a p-value less than 0.05 was considered statistically significant. Results: In our study, out of 1161 patients diagnosed with pneumothorax, 132 were identified as having primary spontaneous pneumothorax (PSP). Among the 132 included PSP patients, 35 of them (26.51%) experienced recurrence during the 3-year short to medium-term follow-up. Among these patients, 30 (85.71%) had a recurrence within the first year, 4 (11.42%) within the second year, and 1 (2.85%) within the third year. Our study revealed that as BMI decreased, patients encountered more recurrences (p=0.028). Patients who were initially treated with tube thoracostomy alone during the first PSP attack were found to have significantly more recurrences compared to the surgical intervention group (p=0.039). In patients who underwent surgical intervention during the initial PSP attack, a lower recurrence rate was observed compared to those who did not receive surgical treatment. Correlation analysis conducted between the Light index and actual pneumothorax volume measurements showed a Pearson correlation coefficient of 0.776 (p<0.001), indicating a strong correlation between the Light index and actual pneumothorax volume measurements. In our study, we found no significant association between other potential risk factors and PSP recurrence. Conclusion: Our study demonstrates a short to medium-term PSP recurrence rate of 26.51%, particularly higher within the first year. Low BMI and the use of only tube thoracostomy have been identified as risk factors for PSP recurrence. Conversely, surgical intervention has been shown to reduce PSP recurrence compared to non-intervention.