In-hospital mortality did not differ between patients hospitalized on the weekend versus weekdays for esophageal variceal bleeding. To our knowledge, our study is the first to examine the weekend effect in patients with variceal hemorrhage. Our findings are consistent with several studies that described mortality according to the day of admission for unspecified UGIB. For example, Bell and Redelmeier (1
) reported no difference in mortality in a cohort of 30,129 Canadian patients (OR 1.08; 95% CI 0.96 to 1.20), and Schmulewitz et al (8
) failed to detect a significant weekend effect among 584 Scottish patients hospitalized for UGIB (OR 1.65; 95% CI 0.69 to 3.71). Similarly, in a study of emergency UGIB admissions in California (USA), Cram et al (2
) reported similar mortality among patients hospitalized on the weekend versus weekdays (OR 1.14; 95% CI 0.92 to 1.42). Importantly, none of these studies controlled for potential confounding by disease-specific markers of illness severity that may differ between patients hospitalized on the weekend and those on weekdays. Our adjustment for the magnitude of bleeding – based on receipt of blood transfusions, endoscopic therapy, balloon tamponade or portosystemic shunt insertion – and severity of the underlying liver disease, as reflected by features of hepatic decompensation, represents a major strength of our analysis. Moreover, because the NIS is a population-based, nationwide database, our results are representative of outcomes and practices across the United States rather than in single states, provinces or even hospitals described in the aforementioned publications (1
There are several potential explanations for our findings. First, a weekend effect may simply not exist for this condition. In Bell and Redelmeier’s study (1
), a significant increase in mortality among patients admitted on the weekend was observed for only 23 of 100 conditions. Likewise, Cram et al (2
) reported a weekend effect for only three of 50 disorders (duodenal ulcer, cancer of the ovary/uterus and cardiovascular symptoms). Thus, hospitalization on the weekend is associated with similar outcomes for the majority of medical and surgical conditions. Most studies (1
) have hypothesized that the weekend effect is attributable to reduced hospital staffing and/or access to specific intensive treatments and procedures on the weekend. In this regard, it is not overly surprising that we did not observe a similar effect in patients with variceal hemorrhage. Current consensus guidelines (10
) recommend that most patients with evidence of liver disease who present with substantial UGIB are assumed to have variceal hemorrhage until proven otherwise. Accordingly, these patients usually receive vasopressor therapy (eg, somatostatin analogues or terlipressin) and expedited upper endoscopy regardless of the day of the week. Conversely, patients without evidence of liver disease and, perhaps, less significant UGIB are more likely to have their endoscopy delayed. Results from the current study and a similar analysis of NIS data in patients with peptic ulcer-related hemorrhage (9
) support these assumptions. Specifically, 45% of patients with variceal bleeding underwent endoscopy on the day of admission versus only 33% of those with peptic ulcer disease (9
). An alternative explanation for our findings is that our assessment of the influence of weekend admission on mortality is an underestimate because patients admitted on weekends typically ‘crossover’ to receive weekday care and vice versa (2
). Finally, we cannot exclude unmeasured differences between processes of care and patient characteristics between weekend and weekday admissions that may have confounded our results. For example, due to limitations in the NIS database, we could not address issues that are vital to the outcomes of variceal bleeding including the quality of resuscitation, endoscopic therapy and general medical care of the cirrhotic patient, or the use of antibiotics for prophylaxis of bacterial infections (10
). Similarly, limitations in clinical and laboratory data in the NIS database hinder complete adjustment for the severity of the bleeding episode or underlying liver disease (eg, using the Child-Pugh or Model for End-Stage Liver Disease scores) (24
). We would argue, however, that patients admitted on the weekend were slightly sicker than individuals hospitalized during the week. For example, weekend patients had a higher prevalence of coagulopathy and were more likely to be admitted emergently (). Such incomplete case-mix adjustment would tend to exaggerate any mortality increase observed in weekend patients and the increase that we observed was not statistically significant.
Although overall in-hospital mortality due to variceal hemorrhage was similar between weekday and weekend admissions, weekend patients were less likely to undergo endoscopy within the first few days of admission, although differences were small. For example, by the end of the second day, 81% of patients hospitalized on a weekday had undergone endoscopy versus 75% of those admitted on the weekend (OR 0.68; 95% CI 0.63 to 0.73). Similarly, the proportion of patients who received a portosystemic shunt within the first few days of admission was significantly lower among weekend hospitalizations (43% versus 54% admitted on a weekday; OR 0.64; 95% CI 0.50 to 0.83). These findings support previous studies demonstrating the impact of weekend admissions on the timeliness of certain procedures and tests. For example, in an analysis of 126,754 patients admitted emergently in Canada, Bell and Redelmeier (28
) described longer mean wait times for upper endoscopy (2.1 days versus 1.9 days), echocardiography (2.5 days versus 2.3 days), and ventilation-perfusion lung scanning (1.9 days versus 1.4 days; P<0.0001 for all comparisons) among patients hospitalized on the weekend. Similarly, Kostis et al (4
) reported significant reductions in rates of cardiac catheterization, coronary angioplasty and coronary artery bypass grafting by the second day of admission in an analysis of New Jersey (USA) hospitalizations for acute myocardial infarction. The magnitudes of these reductions were similar to those observed in our analysis, and several of these differences persisted 30 days after admission. The authors concluded that these delays mediated, at least in part, the 7.5% relative increase in 30-day mortality observed among patients hospitalized on the weekend. Our results suggest that delays in endoscopic intervention in weekend patients are not long enough to increase the in-hospital death rate in this subgroup. In fact, our multivariate analysis suggests that the timing of endoscopy is likely a reflection of the severity of patient presentation rather than a mediator of mortality. Specifically, for each additional day of delay to endoscopy, the odds of mortality decreased 6%. Similarly, endoscopy on the day of admission was associated with a 45% increase in the odds of death. These findings suggest that American clinicians are appropriately triaging their patients such that especially sick individuals receive accelerated endoscopy whereas endoscopy is delayed in those who are less severely ill. An alternative, but far less likely explanation, is that early endoscopy is harmful, for example, due to an increased risk of complications such as oxygen desaturation (29
In addition to mortality, we describe a 4% increase in adjusted hospital charges in patients hospitalized for variceal bleeding on the weekend. LOS did not differ between groups. Similar findings have been reported for other conditions (9
). For example, in a study of percutaneous coronary revascularization, Ellis et al (30
) identified weekend delays as a factor associated with higher costs. In patients with peptic ulcer-related hemorrhage, weekend admission is associated with a 6% increase in hospital charges (9
). These effects may be mediated, at least in part, by delays in receiving endoscopy for patients admitted on the weekend. Alternatively, more intensive resource use by more severely ill patients hospitalized on the weekend (as described above) may have played a role. As expected, measures of increased disease severity and the use of certain procedures (eg, portosystemic shunts) were associated with higher costs in our analysis (data not shown).
Our study has several limitations. As with all studies using administrative data, the validity of the diagnosis and procedure codes we used must be considered (31
). It is unlikely, however, that the accuracy of this information would systematically vary between weekend and weekday admissions. Secondly, a substantial number of patients were excluded from our analyses because of endoscopic details and missing data regarding mortality – predominantly transfers to other institutions. These patients may have differed in disease severity from those included in our cohort. For example, more severely ill patients may have been transferred to other institutions (eg, tertiary care centres) and thus excluded from our analyses. This issue highlights a limitation of the NIS database, namely that linkage of individual patients between or within hospitals cannot be performed; thus, we could not adjust for within-patient correlations (ie, in those with multiple admissions). Finally, our mortality analyses were limited to in-hospital deaths. Whether an association exists between weekend admission and increased mortality due to variceal bleeding over longer-term follow-up (eg, at 30 days or one year), as observed in some conditions (4
), warrants investigation.