Primary and Secondary Spontaneous Pneumothorax: Prevalence, Clinical Features, and In-Hospital Mortality.

Background. Optimal treatment practices and factors associated with in- hospital mortality in spontaneous pneumothorax (SP) are not fully understood. We evaluated prevalence, clinical characteristics, and in- hospital mortality among Japanese patients with primary or secondary SP (PSP/ SSP). Methods. We retrospectively reviewed and stratified 938 instances of pneumothorax in 751 consecutive patients diagnosed with SP into the PSP and SSP groups. Factors associated with in- hospital mortality in SSP were identified by multiple logistic regression analysis. Results. In the SSP group (N= 327; 34.9%), patient age, requirement for emergency transport, and length of stay were greater (all P< 0.001), while the prevalence of smoking (N= 0.023) and number of surgical interventions (P < 0.001) were lower compared to those in the PSP group (N= 611; 65.1%). Among the 16 in- hospital deceased patients, 12 (75.0%) received emergency transportation and 10 (62.5%) exhibited performance status (PS) of 3- 4. In the SSP group, emergency transportation was an independent factor for in- hospital mortality (odds ratio 16.37; 95% confidence interval, 4.85- 55.20;N < 0.001). Conclusions. The prevalence and clinical characteristics of PSP and SSP differ considerably. Patients with SSP receiving emergency transportation should receive careful attention.