Weekend effect in non-elective abdominal aortic aneurysm repair

Abstract

BackgroundThe ‘weekend effect’ describes the phenomenon where patient outcomes appear worse for those admitted at the weekend. It has been used recently to justify significant changes in UK health policy. Recent evidence has suggested that the effect may be due to a combination of inadequate correction for confounding factors and inaccurate coding. The effects of these factors were investigated in patients with acute abdominal aortic aneurysm (AAA).MethodsPatients undergoing non‐elective AAA repair entered into the UK National Vascular Registry from January 2013 until December 2015 were included in a case–control study. The patients were divided according to whether they were treated during the week (Monday 08.00 hours to Friday 17.00 hours) or at the weekend. Data extracted included demographics, co‐morbidities, preoperative medications and baseline blood test results, as well as outcomes. Coding issues were investigated by looking at patients treated for ruptured, symptomatic or asymptomatic AAA within the non‐elective cohort. The primary outcome was in‐hospital mortality. Secondary outcomes included length of inpatient stay, and cardiac, respiratory and renal complications.ResultsThe mortality rate appeared to be higher at the weekend (odds ratio (OR) 1·69, 95 per cent c.i. 1·47 to 1·94; P < 0·001), but this effect disappeared when confounding factors and coding issues were corrected for (corrected OR for ruptured AAA 1·09, 0·92 to 1·29; P = 0·330). Differences in outcomes were similar for prolonged length of hospital stay (uncorrected OR 1·21, 95 per cent c.i. 1·06 to 1·37, P = 0·005; corrected OR for ruptured AAA 1·06, 0·91 to 1·10, P = 0·478), and morbidity outcomes.ConclusionAfter appropriate correction for confounding factors and coding effects, there was no evidence of a significant weekend effect in the treatment of non‐elective AAA in the UK.

Editor's Choice – Systematic Review and Meta-Analysis of the Effect of Weekend Admission on Outcomes for Ruptured Abdominal Aortic Aneurysms: A Call for an Equitable Seven Day Vascular Service

“…Two cohorts comprising of a total of 8 921 patients (2 484 treated over the weekend and 6 437 treated on a weekday) reported data regarding hospital length of stay. 7,18 One reported data on hospital length of stay suitable for meta-analysis demonstrating a shorter length of stay for those admitted over the weekend, but the difference was not statistically significant (OR e0.60, 95% CI e1.27 e 0.07, p ¼ .080) (Fig. 1G).…”

“…Five cohorts comprising of a total of 48 651 patients reported adjusted in hospital mortality data. 6,7,16,20 Meta-analysis of these cohorts found a significantly greater risk of in hospital death in patients treated over the weekend (OR 1.16, 95% CI 1.09 e 1.23, p < .001). The statistical between cohort heterogeneity was negligible (p ¼ .44, I 2 ¼ 0%) (Fig.…”

“…Pauls et al 2 found there to be a statistically significantly higher mortality for all hospital admissions over the weekend compared with their weekday counterparts (OR 1.19 95% CI 1.14 e 1.23). Two previous meta-analyses have been performed to assess the weekend effect for all aortic aneurysms 27 and all ruptured aortic aneurysms and aortic dissections, with Open OR (95% CI) y O'Donnell (2019) 13 3 112 NR NR NR NR NR NR Ambler (2017) 7 3 121 NR 1.06 (0.91e1.10) NR NR NR NR Glance (2016) 14 3 16 4 2 2 8 Gallerani (2013) 22 3 2 2 7 Gallerani (2012) 19 3 2 2 7 Bell (2001) 6 3 2 2 7…”

“…A recent meta-analysis looking into ruptured abdominal and thoracic aortic aneurysms as well as acute aortic dissection including 116 195 patients suggested there is an out of hours effect for this patient group; 3 however, other studies limited just to rAAA suggest the effect may not be significant. 7 Therefore, a metaanalysis was undertaken to determine whether weekend admission for rAAA is associated with poorer outcomes.…”

Reply

“…However, some evidence suggests that both changes in EVAR rates and centralization of vascular services are associated with outcome of patients operated on at the weekend. Botes et al correctly point out differences from a similar study by Ambler et al 5 Comparison between the studies appears challenging as Ambler et al limited their analyses to nonelective infrarenal AAA, whereas we also included ruptured thoracic and thoracoabdominal aortic aneurysms to reflect treatment reality during off-hours as ruptured aortic aneurysms respect neither anatomic nor infrastructural borders. However, we adjusted the multivariable analyses accordingly and additionally performed a propensity score matching to account for possible confounders (eg, for case mix effects).…”