Contact: Patrick Phillips, Patrick.phillips@sheffield.ac.uk School Of And Health Related Research Volume-outcome relationships in peripheral vascular surgery: an overview of reviews Phillips, P; Poku, E; Essat, M; Woods, HB; Goka, EA; Kaltenthaler, EC; Shackley, P; Michaels, JA. School of Health and Related Research (ScHARR), University of Sheffield, S1 4DA, UK Background: The debate regarding the relationship between volume (by individual clinicians or hospitals) and outcomes has been informed by suggestions that clinicians and hospitals that perform high volumes of procedures achieve better outcomes as a result of ‘practice making perfect’ or ‘preferential referral’. As a preliminary stage of a proposed systematic review investigating the volume outcome relationship in peripheral vascular surgery to inform re-configuration of vascular services in the UK, an overview of reviews was conducted. Aim: To identify and appraise existing systematic reviews evaluating the relationship between the volume of vascular procedures undertaken and selected outcomes including mortality, stroke and amputation. Methods: Comprehensive searches of MEDLINE, EMBASE and the Cochrane Library were conducted to March 2015, supplemented by reference list and citation searches . Eligible studies were English language articles that investigated the volume-outcome relationship in the treatment of peripheral vascular disease, using a systematic review methodology. Study selection, data extraction and quality assessment were conducted by a single reviewer, the AMSTAR tool was used for quality assessment. A narrative synthesis was performed. Results: Available data: Of 710 screened records 11 relevant systematic reviews were identified examining the volume-outcome relationship in three disease areas; abdominal aortic aneurysm (AAA),carotid procedures (C) and lower limb procedures (LL). Volume outcome relationship: Results were suggestive of an inverse volume outcome relationship in AAA repair, but there was less evidence for such a relationship for the other vascular procedures. The most recent review was published in 2010 and mostly included US data and/or evidence that pre-dated recent technological advances (specifically the increasing use of endovascular procedures). Additionally, several relevant UK and European studies identified by preliminary searches were not included in the previously published reviews. Quality of studies: Overall, the quality of reviews was low with particular issues relating to protocol registration, quality assessment and study selection. Reference condition Awopetu 2010 (LL) Gandjour 2003 (C, LL, AAA) Henebiens 2007 (AAA) Holt 2007 (C) Holt 2007a (AAA) Hoornweg 2008 (AAA) Killeen 2007 (C, LL, AAA) Marlow 2010 (AAA) Shackley 2006 (C, LL, AAA) Wilt 2006 (AAA) Young 2007 (AAA) AMSTAR score (out of 11) 5.5 5 6.5 4.5 4 7.5 6 Conclusion: No recent methodologically sound systematic review was identified. Current evidence based on low quality studies suggests an inverse relationship between the volume of AAA procedures conducted in hospital and mortality . Re-configuration of vascular services must be based on more robust and contemporary evidence reflecting recent technological advancements in vascular procedures, and should be more directly relevant to the UK and European context. Funding and disclaimer: This poster presents independent research funded by the National Institute for Health Research (NIHR) under the Programme Grants for Applied Research programme (RP-PG-1210-12009). The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health Contact: Patrick Phillips, Patrick.phillips@sheffield.ac.uk School of Health and Related Research (ScHARR), University of Sheffield, S1 4DA, UK www.facebook.com/scharrsheffield ruth.wong@sheffield.ac.uk