Die Vorhersage gesundheitsbezogener Lebensqualität durch Selbstwirksamkeitserwartung und kardiovaskuläre Risikofaktoren bei Patienten mit ischämischem Schlaganfall

The incidence of strokes in Germany has risen throughout the last years. This being one of the main reasons for disability, the quality of life of the patients is impaired (Centers for Disease Control and Prevention (CDC) 2009). Up to now a number of risk factors for cardiovascular disease have been identified that pro­mote the development of strokes. These are for example hypertension, diabetes, hypercholes­terolemia and obesity (As et al. 2013; Kirtania et al. 2013; O'Donnell et al. 2010; Zhao et al. 2009). Different studies were able to show a relation between the risk factors and health re­lated quality of life (HRQoL) (Larsson et al. 2002; Poljicanin et al. 2010; Sullivan et al. 2007). Moreover, there is a correlation between HRQoL and self-efficacy beliefs (Andenæs et al. 2014; Bentsen et al. 2010; Phillips und McAuley 2014; Weng et al. 2010; Yeung, N C Y und Lu 2014). This concept was firstly described by Albert Bandura in his Social Cognitive Theory (Bandura 1977) and means people's beliefs about their capabilities to have influence on their own lives. Previously it has been demonstrated, that self-efficacy is associated with different health-pro­moting behaviours (Bandura 2004), as well as in conjunction with behaviours that lower the cardiovascular risk (Aljasem et al. 2001; Ogedegbe et al. 2003; Richman et al. 2001; Sarkar et al. 2006; Steele et al. 2011). Aim of this study was to predict health related quality of life through a multiple mediation ana­lysis in a longitudinal design 24 months after a stroke with self-efficacy measured directly after the stroke. The relationship would be mediated by the cardiovascular risk factors blood pres­sure, HbA1c, LDL and BMI. The examination took place at the Universitätsklinikum Gießen und Marburg, Standort Mar­burg, during the initial stay as well as 6, 12 and 24 months after the stroke. All the instruments used have been validated in former studies (Post et al. 2011; Rabin und Charro 2001; Ramachaudran 1994). All in all, the data of 374 patients was analysed. The demographic variables were - apart from the level of education - comparable with these of the citizens of Germany as well as with these of the populations of other big stroke studies (Kelly-Hayes et al. 2003; Kolominsky-Rabas et al. 1998; Palm et al. 2010). A majority of the patients had hypertension, hypercholesterolemia and were overweight, a third had diabetes. For the multiple mediation analysis the data of 111 (calculated with the EQ-5D) respective 80 (calculated with the SSQoL-12) patients could be used. Thus, the statistical power was considerably reduced. None of the assumed correlations was statistically significant. Apart of the limited statistical power, the results can be explained with the inaccurate specificity of the data. In former studies the measured self-efficacy beliefs for predicting HRQoL were specific for a particular disease (Bentsen et al. 2010; Motl et al. 2013; Richman et al. 2001; Steele et al. 2011). Relating to the risk-factors, there were meas­ured behaviours like the compliance for taking medicine or the adherence to a diet instead of the specific factors HbA1c and LDL, which could also be influenced of a third, unknown variable (Aljasem et al. 2001; Sarkar et al. 2006). Also, former studies that dealt with the quality of life were looking at the whole population of a country, where the value of the quality of life was much higher than in the actual sample. It is possible that the relationship between cardiovascular risk factors and HRQoL just occurs at a higher level of HRQoL. The risk factors as well as their standard-deviations were relatively low, apart of the BMI. Thus, just a small part of the variance could be explained through self-effic­acy. In future studies, the incentive for being part of the study should be increased, so that the dro­pout-rate is lower and the statistical power is greater. Furthermore, self-efficacy should be measured as specific as possible and cardiovascular risk factors collected as part of health-pro­moting behaviours. The data collection should occur as a prospective cohort analysis for gain­ing information of the basal values of the variables.