Measuring Quality Improvement in Acute Ischemic Stroke Care: Interrupted Time Series Analysis of Door-to-Needle Time

BACKGROUND: In patients with acute ischemic stroke, early treatment with recombinant tissue plasminogen activator (rtPA) improves functional outcome by effectively reducing disability and dependency. Timely thrombolysis, within 1 h, is a vital aspect of acute stroke treatment, and is reflected in the widely used performance indicator ‘door-to-needle time’ (DNT). DNT measures the time from the moment the patient enters the emergency department until he/she receives intravenous rtPA. The purpose of the study was to measure quality improvement from the first implementation of thrombolysis in stroke patients in a university hospital in the Netherlands. We further aimed to identify specific interventions that affect DNT. METHODS: We included all patients with acute ischemic stroke consecutively admitted to a large university hospital in the Netherlands between January 2006 and December 2012, and focused on those treated with thrombolytic therapy on admission. Data were collected routinely for research purposes and internal quality measurement (the Erasmus Stroke Study). We used a retrospective interrupted time series design to study the trend in DNT, analyzed by means of segmented regression. RESULTS: Between January 2006 and December 2012, 1,703 patients with ischemic stroke were admitted and 262 (17%) were treated with rtPA. Patients treated with thrombolysis were on average 63 years old at the time of the stroke and 52% were male. Mean age (p = 0.58) and sex distribution (p = 0.98) did not change over the years. The proportion treated with thrombolysis increased from 5% in 2006 to 22% in 2012. In 2006, none of the patients were treated within 1 h. In 2012, this had increased to 81%. In a logistic regression analysis, this trend was significant (OR 1.6 per year, CI 1.4-1.8). The median DNT was reduced from 75 min in 2006 to 45 min in 2012 (p < 0.001 in a linear regression model). In this period, a 12% annual decrease in DNT was achieved (CI from 16 to 8%). We could not find a significant association between any specific intervention and the trend in DNT. CONCLUSION AND IMPLICATIONS: The DNT steadily improved from the first implementation of thrombolysis. Specific explanations for this improvement require further study, and may relate to the combined impact of a series of structural and logistic interventions. Our results support the use of performance measures for internal communication. Median DNT should be used on a monthly or quarterly basis to inform all professionals treating stroke patient of their achievements.