Research in context
Evidence before this study
Between Jan 1, 1980, and May 31, 2015, we searched MEDLINE for English-language studies published before June, 2015, investigating temporal variation in health-care quality. Our main focus was to identify studies of stroke care, but we also searched for studies done in other clinical settings. Our search terms were “Weekend”, “Weekend effect”, “Off hours”, “Temporal variation”, “AND Stroke”, “AND quality”. Studies of the weekend effect were identified in a wide range of clinical settings and geographical locations, describing evidence of poorer outcomes for patients admitted on the weekend or overnight with myocardial infarction, stroke, and general emergency admissions. We identified only a few studies that examined variation across both time of admission and day of week, including a study of obstetric outcomes in California, USA, and a study of hospital inpatients from Australia.
Added value of this study
Our study shows that in acute stroke care, the weekend effect is just one of several patterns of variation in quality that occur in real-world practice. Quality varied across the whole week, and different aspects of quality showed different patterns of variation.
Implications of all the available evidence
These findings imply that in acute stroke care, the weekend effect is a simplification of the true extent of temporal variation in health-care quality that occurs across the week. A focus only on reducing differences in care quality between weekends and weekdays will therefore not fully address the problem of variation in health-care quality across the week. Although we only examined care quality in the stroke setting, findings from previous studies assessing the weekend effect in a wide variety of clinical settings suggest that weekly variations in quality might also be pervasive across acute health-care settings. Such variations should be sought for and be a focus of quality improvement efforts.