The Frequency and Timing of Recurrent Stroke: An Analysis of Routine Health Insurance Data

Stroke is among the leading causes of death in Germany and one of the main reasons for handicap and disability. The risk factors for stroke include hypertension, metabolic disorders, and diabetes. An estimated 250 000 persons sustain a stroke in Germany each year. German data on the occurrence of stroke, and of recurrent stroke in particular, are still inadequate. The main objective of this study was to determine the frequency and timing of recurrent stroke.

The analyses were based on routine data of the AOK statutory health insurance fund in the German federal state of Lower Saxony. Inpatient billing and diagnosis data were used to identify initial and recurrent strokes (ICD-10 I60-I64). The derived incidence and prevalence were standardized for age and sex. The risks of recurrence and mortality were estimated with Kaplan-Meier analyses and Cox regressions.

In 2010/2011, the standardized incidence of stroke was 292 per 100 000 persons per year, and the standardized prevalence was 336 per 100 000 persons. The risk of recurrence was 1.2% in the first 30 days, 3.4% within 90 days, 7.4% within 1 year, and 19.4% within 5 years. The mortality after an initial stroke was 6.8% in the first 30 days, 9.4% within 90 days, 17.0% within 1 year, and 45% within 5 years. Patients with hemorrhagic strokes had higher mortality. Treatment in a stroke unit was associated with lower mortality.

Patients with acute stroke should be treated in a specialized center whenever possible. After hospital discharge, stroke patients should be followed up at short intervals and any risk factors for stroke should be treated.