title: Primary spontaneous pneumothorax: 1-year recurrence rate after simple aspiration.
abstract: OBJECTIVE
  Recurrence rate is an important factor to consider when choosing the modality of treatment for primary spontaneous pneumothorax. The recurrence rate after simple aspiration has only been previously reported in several relatively small studies. The objectives of this study was to investigate the 1-year recurrence rate of primary spontaneous pneumothorax after treatment by simple aspiration and the potential risk factors for recurrence.
  
  
  METHODS
  A retrospective cohort study was performed over a 2-year period on 91 consecutive patients with primary spontaneous pneumothorax who were treated with simple aspiration. The setting was an emergency department of a 1400-bed university teaching hospital in Hong Kong. Recurrence within 1 year and associated risk factors were assessed by telephone follow-up interviews. The factors evaluated were age, sex, side of pneumothorax, previous and present smoking history, history of previous pneumothorax, size of pneumothorax at initial assessment, volume of air aspirated, and final outcome.
  
  
  RESULTS
  The overall 1-year recurrence rate was 15.7% [95% confidence interval (CI), 8.9-25.0%]. The recurrence rate for patients who had successful simple aspiration was 17.6% (95% CI, 8.0-32.1%). In patients who had successful aspiration, the median size of pneumothorax at initial presentation for those with recurrence was 17.5% (95% CI, 12.0-23.0%), compared with 25.0% (95% CI, 22.7-30.6%) for those without recurrence (P = 0.044).
  
  
  CONCLUSIONS
  The 1-year recurrence rate after successful simple aspiration for primary spontaneous pneumothorax in Chinese patients in Hong Kong is not high. Recurrence within 1 year appears to be associated with smaller initial size of pneumothorax.
authors.affiliation: Accident & Emergency Medicine Academic Unit, Prince of Wales Hospital, Shatin, The Chinese University of Hong Kong, Hong Kong, China. stewart_chan@hotmail.com
authors.forename: Stewart S W
authors.initials: SS
authors.lastname: Chan
authors.forename: Timothy H
authors.initials: TH
authors.lastname: Rainer
mesh_terms: D000328:Adult; D015331:Cohort Studies; D004635:Emergency Medicine / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D011030:Pneumothorax / Q000453:epidemiology / Q000628:therapy*; D012008:Recurrence; D012189:Retrospective Studies; D013396:Suction / Q000379:methods*; D016896:Treatment Outcome