Restriction of therapy mainly explains lower thrombolysis rates in reduced stroke service levels

Abstract

Objective: To assess the influence of preexisting disabilities, age, and stroke service level on standardized IV thrombolysis (IVT) rates in acute ischemic stroke (AIS).

Methods: We investigated standardized IVT rates in a retrospective registry-based study in 36,901 patients with AIS from the federal German state Baden-Wuerttemberg over a 5-year period. Patients admitted within 4.5 hours after stroke onset were selected. Factors associated with IVT rates (patient-level factors and stroke service level) were assessed using robust Poisson regression modeling. Interactions between factors were considered to estimate risk-adjusted mortality rates and potential IVT rates by service level (with stroke centers as benchmark).

Results: Overall, 10,499 patients (28.5%) received IVT. The IVT rate declined with service level from 44.0% (stroke center) to 13.1% (hospitals without stroke unit [SU]). Especially patients >80 years of age and with preexisting disabilities had a lower chance of being treated with IVT at lower stroke service levels. Interactions between stroke service level and age group, preexisting disabilities, and stroke severity (all p < 0.0001) were observed. High IVT rates seemed not to increase mortality. Estimated potential IVT rates ranged between 41.9% and 44.6% depending on stroke service level.

Conclusions: Differences in IVT rates among stroke service levels were mainly explained by differences administering IVT to older patients and patients with preexisting disabilities. This indicates considerable further potential to increase IVT rates. Our findings support guideline recommendations to admit acute stroke patients to SUs.