Shackley P, Slack R, Booth A, Michaels J
Sheffield Health Economics Group, ScHARR, UK.
Eur J Vasc Endovasc Surg. 2000 Oct;20(4):326-35. doi: 10.1053/ejvs.2000.1188.
to examine the evidence for the existence, or otherwise, of a positive volume-outcome relationship in the area of peripheral vascular surgery.
systematic overview of prospective or retrospective volume-outcome studies.
seven bibliographic databases were searched for English-language articles published between 1986 and 1998.
thirty-six articles published in peer-reviewed journals; excluding editorials, letters or abstracts; and addressing volume and outcome in peripheral vascular surgery. Criteria were applied and agreed by consensus between two of the authors.
the articles identified were independently assessed by two of the authors. Studies were categorised into three distinct areas - carotid endarterectomy- (17 studies), abdominal aortic aneurysm repair (16 studies) and other vascular interventions (four studies). Within each category studies were further classified according to full adjustment, partial adjustment or no adjustment for case mix. Where discrepancies arose, decisions were referred to a third author for arbitration.
findings for carotid endarterectomy identified a positive volume-outcome relationship for both mortality and stroke at the physician level. There was less support for a positive relationship for mortality at the hospital level, and no evidence of benefits for stroke in higher volume hospitals. If only studies making a full adjustment for case mix are included, there is no clear support from statistically significant evidence for or against a positive volume-outcome relationship. For repair of unruptured abdominal aortic aneurysms there is evidence of a positive volume-outcome relationship at both the physician and hospital level, with evidence being particularly strong at the level of the hospital. For ruptured aneurysms the evidence is suggestive of there not being a positive volume-outcome relationship at the hospital level, while for physicians the evidence is more balanced with no clear support either way. For other vascular interventions there were insufficient studies (n=4) from which to draw meaningful conclusions.
our results show that evidence of a relationship between volume and outcome in peripheral vascular surgery may be attributable to factors such as lack of adjustment for case-mix, different definitions of volume and poor quality of studies, especially those of retrospective design. Future studies should address these deficiencies by making full adjustment for case mix and by being prospective in design.
探讨外周血管外科领域中手术量与治疗效果之间是否存在正向关系的证据。
对前瞻性或回顾性手术量-治疗效果研究进行系统综述。
检索了7个文献数据库，以查找1986年至1998年间发表的英文文章。
36篇发表于同行评审期刊的文章；排除社论、信件或摘要；涉及外周血管外科的手术量和治疗效果。由两位作者达成共识并应用相关标准。
两位作者对筛选出的文章进行独立评估。研究分为三个不同领域——颈动脉内膜切除术（17项研究）、腹主动脉瘤修复术（16项研究）和其他血管干预（4项研究）。在每个类别中，研究根据对病例组合的完全调整、部分调整或未调整进一步分类。出现分歧时，交由第三位作者进行仲裁。
颈动脉内膜切除术的研究结果表明，在医生层面，手术量与死亡率和中风之间存在正向关系。医院层面上，对于死亡率存在正向关系的支持较少，且没有证据表明手术量较高的医院在中风方面有获益。如果仅纳入对病例组合进行完全调整的研究，则没有统计学上显著的证据明确支持或反对手术量与治疗效果之间的正向关系。对于未破裂腹主动脉瘤的修复，在医生和医院层面均有证据表明存在正向关系，且在医院层面证据尤为有力。对于破裂动脉瘤，在医院层面证据表明不存在正向关系，而对于医生而言，证据较为平衡且没有明确支持哪一方。对于其他血管干预，研究数量不足（n = 4），无法得出有意义的结论。
我们的结果表明，外周血管外科手术量与治疗效果之间关系的证据可能归因于病例组合调整不足、手术量定义不同以及研究质量差等因素，尤其是那些回顾性设计的研究。未来的研究应通过对病例组合进行完全调整和采用前瞻性设计来解决这些不足。
