Background: Quality assurance for acute in-hospital care in Germany is based on compulsory comparisons between institutions, so-called external quality assurance (EQA). The effectiveness of EQA has not yet been adequately studied. The purpose of the QUASCH project, which is supported by the Innovation Fund of the Federal Joint Committee, is to investigate the association between EQA and health care outcomes, specifically with respect to stroke.
Methods: The analyses were based on data from 379 825 patients insured by the AOK health insurance fund who were acutely admitted to a hospital because of stroke over the period 2007-2017. Data on 47 659 patients were derived from EQA documentation in the state of Hesse, in which stroke EQA had already been introduced in 2003; data on the remaining 332 166 patients were from other federal states, where 117 734 of these patients had been treated under EQA conditions. The association of EQA with mortality over the period of observation was analyzed by multivariate Cox regression, with the following covariates: age, sex, comorbidities, time period of occurrence, nursing care level, type of stroke, socio-economic deprivation in the region of origin, and treatment in a stroke unit.
Results: Compared to treatment without EQA, mortality risk under EQA in the state of Hesse was significantly lower (hazard ratio [HR]: 0.93; 95% confidence interval: [0.92; 0.95]). The reduction in mortality risk with EQA was somewhat lower in the other federal states (HR: 0.96 [0.95; 0.97]). Treatment in a stroke unit was associated with a mortality risk that was lower still (HR: 0.86 [0.85; 0.87]). Mortality risk rose with age, comorbidities, and need for nursing care; it was lower in women and in persons whose stroke occurred in a later period.
Conclusion: Quality assurance measures are associated with lower mortality risk after stroke. The concentration of care in specially qualified institutions is associated with stronger effects than EQA alone.