In this cohort, patients admitted on weekends did not have a higher rate of in-hospital mortality or 90-day mortality when compared to weekday admissions. Patients admitted on weekends also did not have worse functional outcome (mRS 3–6) at discharge or at 90 days. Further, patients admitted and treated with IV t-PA on weekends did not have higher rates of sICH when compared with their weekday counterparts. The lack of a weekend effect cannot be attributed to baseline variables that affect outcome, as there were no significant differences in weekday and weekend groups with respect to age, NIHSS scores, and admission glucose levels. Further, IV t-PA treatment rates were not significantly different in patients treated on weekends, as compared to their weekday counterparts.
The weekend effect was absent when the data from site 1 was investigated. This result then prompted us to assess the weekend effect at a separate CSC. A significant concern is that of the disparate populations at site 1 and site 2. Despite the differences noted in demographics at the 2 sites, the weekend effect was still not observed in the second dataset. Although a homogeneous patient sample may be desirable, the lack of a weekend effect seen even in these differing patient populations may support generalizability to the population as a whole. Further, when outcomes common to both sites were combined to generate an even larger sample, no significant differences in in-hospital mortality were observed.
The acute coronary literature has shown that patients with more severe disease tend to present on weekends [17
]. It has been suggested that the increased mortality previously seen in weekend stroke patients may be due to the different level of severity of disease [18
]. Our study found no significant differences in NIHSS scores, age, race, or admission glucose levels when comparing the weekend and weekday groups. In addition, we found no significant difference in IV t-PA treatment rates.
Previous studies have also reported the rate of weekend admissions in certain disease processes to be higher than that which would be expected (2/7 or 28.6%) [1
]. While our study did not find the rate of weekend admissions for AIS-TPA to be significantly different between the 2 sites (37, 35%), it did find the weekend stroke rate to be greater than the expected 28.6% (2/7). This increased incidence of stroke on the weekends is consistent with previous reports of an increased incidence of stroke on holidays and weekends [19
Given the above results, it is important to point out that this study is limited by its small sample size and should therefore be interpreted with caution. Our design is also limited by its retrospective analysis of prospectively collected data. Future prospective designs may lend additional support to these findings. Each database was designed independently; thus, not all outcome variables were available at each site. Site 1 provided in-hospital adverse events and discharge functional outcome, while site 2 provided functional outcome and mortality at 90 days, thus limiting the number of patients of which every variable was collected. Fortunately, both sites had in-hospital mortality data available; thus, we were able to combine the datasets for this important outcome variable. Patient data collection time periods were slightly different at each site. Similarly, practice patterns may have been different at individual institutions. In spite of these differences, our data did not show a statistically significant difference for in-hospital mortality.
While this study is limited by its small sample size, our results suggest that CSC may erase the previously reported ‘weekend effect’ in acute ischemic stroke patients. Compared to other reports, the absence of the weekend effect in our study may be the result of the 24/7 availability of stroke specialists, trained stroke-nursing expertise, or advanced neuroimaging capabilities at CSC, as previously described by the Brain Attack Coalition [3
The Brain Attack Coalition described a CSC as a facility with the necessary personnel, infrastructure, expertise, and programs to diagnose and treat stroke patients requiring a high intensity of medical and surgical care, specialized tests, or interventional therapies. This coalition further suggested that an additional function of a CSC would be to act as a resource center for other facilities in their region, such as primary stroke centers [20
]. If CSC were intended to parallel trauma centers, this raises the question as to whether weekend stroke patients should bypass local facilities and be brought directly to a CSC in locations where this is an option. Another option would be to establish ‘drip and ship’ relationships with noncomprehensive stroke centers where acute ischemic stroke patients arriving on a weekend could be treated with IV t-PA when appropriate, and then immediately transferred to a comprehensive stroke center where the resources are available 24/7.
Our data did not confirm recent reports which showed that both ischemic and hemorrhagic stroke patients had higher mortality when presenting on the weekend [3
]. In those studies, patients were primarily treated at primary stroke centers or community hospitals without dedicated university-affiliated stroke programs. It is possible that formation of comprehensive stroke centers and appropriate network strategies may ameliorate or prevent the weekend phenomenon. Additional study is warranted to further investigate these promising findings.