BACKGROUND Whether conservative management is an acceptable alternative to interventional management for uncomplicated, moderate-to-large primary spontaneous pneumothorax is unknown. METHODS In this open-label, multicenter, noninferiority trial, we recruited patients 14 to 50 years of age with a first-known, unilateral, moderate-to-large primary spontaneous pneumothorax. Patients were randomly assigned to immediate interventional management of the pneumothorax (intervention group) or a conservative observational approach (conservative-management group) and were followed for 12 months. The primary outcome was lung reexpansion within 8 weeks. RESULTS A total of 316 patients underwent randomization (154 patients to the intervention group and 162 to the conservative-management group). In the conservative-management group, 25 patients (15.4%) underwent interventions to manage the pneumothorax, for reasons prespecified in the protocol, and 137 (84.6%) did not undergo interventions. In a complete-case analysis in which data were not available for 23 patients in the intervention group and 37 in the conservative-management group, reexpansion within 8 weeks occurred in 129 of 131 patients (98.5%) with interventional management and in 118 of 125 (94.4%) with conservative management (risk difference, -4.1 percentage points; 95% confidence interval [CI], -8.6 to 0.5; P = 0.02 for noninferiority); the lower boundary of the 95% confidence interval was within the prespecified noninferiority margin of -9 percentage points. In a sensitivity analysis in which all missing data after 56 days were imputed as treatment failure (with reexpansion in 129 of 138 patients [93.5%] in the intervention group and in 118 of 143 [82.5%] in the conservative-management group), the risk difference of -11.0 percentage points (95% CI, -18.4 to -3.5) was outside the prespecified noninferiority margin. Conservative management resulted in a lower risk of serious adverse events or pneumothorax recurrence than interventional management. CONCLUSIONS Although the primary outcome was not statistically robust to conservative assumptions about missing data, the trial provides modest evidence that conservative management of primary spontaneous pneumothorax was noninferior to interventional management, with a lower risk of serious adverse events. (Funded by the Emergency Medicine Foundation and others; PSP Australian New Zealand Clinical Trials Registry number, ACTRN12611000184976.).

中文翻译：

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自发性气胸的保守治疗与介入治疗。

背景对于无并发症的中度至大型原发性自发性气胸，保守治疗是否是介入治疗的可接受的替代方案尚不清楚。方法 在这项开放标签、多中心、非劣效性试验中，我们招募了 14 至 50 岁、首次已知单侧中度至大量原发性自发性气胸的患者。患者被随机分配接受气胸立即介入治疗（干预组）或保守观察方法（保守治疗组），并随访 12 个月。主要结果是 8 周内肺复张。结果 共有 316 名患者接受了随机分组（干预组 154 名，保守治疗组 162 名）。在保守治疗组中，由于方案中预先规定的原因，25 名患者 (15.4%) 接受了治疗气胸的干预措施，137 名患者 (84.6%) 没有接受干预。在一项完整病例分析中，干预组有 23 名患者和保守治疗组有 37 名患者没有数据，在 8 周内，131 名接受介入治疗的患者中有 129 名患者（98.5%）出现了复张，125 名患者中有 118 名患者在 8 周内出现了复张。 (94.4%) 采用保守治疗（风险差异，-4.1 个百分点；95% 置信区间 [CI]，-8.6 至 0.5；非劣效性 P = 0.02）；95%置信区间的下限在预先指定的-9个百分点的非劣效性范围内。在一项敏感性分析中，56 天后所有缺失数据均被归咎于治疗失败（干预组 138 名患者中有 129 名患者 [93.5%] 出现复发，保守治疗组 143 名患者中有 118 名患者出现复发 [82.5%]）， -11.0 个百分点（95% CI，-18.4 至 -3.5）的风险差异超出了预先指定的非劣效性界限。与介入治疗相比，保守治疗可降低严重不良事件或气胸复发的风险。结论 虽然主要结果在统计上对缺失数据的保守假设并不稳健，但该试验提供了适度的证据，表明原发性自发性气胸的保守治疗并不劣于介入治疗，且严重不良事件的风险较低。（由急诊医学基金会和其他机构资助；PSP 澳大利亚新西兰临床试验注册号，ACTRN12611000184976。）。