Socioeconomic factors in coronary artery disease – Results from the SPIRR-CAD study

Highlights

• German speaking CAD-patients have social gradients in coronary risk as Anglo-Saxon- and Scandinavian patients

• Among standard coronary risk factors only smoking was higher in low social class

• In contrast the scores of depression, coping and self efficacy measures were statistically significantly socially graded

• Social gradients in emotional factors are stronger and more consistent than social gradients in standard risk factors.

• SES is important and has consequences for which kind of preventive measures should be used.

Abstract

Low socio-economic status (SES) has been associated with an increased coronary risk in Western countries. All stress experiences are more pronounced in low SES patients with stress emanating from problems with family, job, or money.

The SPIRR-CAD study offered an excellent opportunity to examine these risk factors in German speaking mildly and medium depressed patients. In the SPIRR CAD study, a German multi centre randomized clinical trial of 450 male and 120 female coronary patients, we examined the standard and psychosocial risk factor profiles in relation to SES, as assessed by educational level. All differences in risk factors between low and high SES were in the inverse direction. Of standard risk factors, only smoking was socially graded and more common in low SES. Of psychosocial factors and emotions, exhaustion showed the strongest and most consistent inverse social gradient, but also anger, anxiety and depression were socially graded. The findings suggest that in German patients, as in other national groups, social gradients in CHD risk are considerable. They can be ascribed to both psychosocial and to standard risk factors. In the present two years follow-up, the prospective significance of psychological and social risk factors was analyzed showing that emotional factors played an important role, in that low and high SES patients differed in the expected direction. However, the differences were not statistically significant and therefore firm conclusions from follow up were not possible.

Trial registration: ISRCTN 76240576; NCT00705965

Introduction

Low socio-economic status is associated with an increased risk of coronary disease in Western countries [1], [2], [3], [4], [5]. The inverse socio-economic gradients found in the early White Hall studies in London were clear and convincing. Coronary heart disease was more frequent in low SES with a similar dose response gradient across all social strata [6]. Such gradients have been reconfirmed in many studies in various populations from the UK, the US, the Netherlands, and Scandinavian countries [7], [8], [9].

However, these gradients have been less intensively studied in German speaking countries. It has been pointed out that the proportion of students who graduate from secondary school and thereby are allowed to pursue academic studies is low within the German educational system. It has even been claimed that the difference between the very rich and the very poor is larger in Germany than anywhere else except the USA [11]. It has been argued that if it was possible to raise the general educational level of the entire population, one might also improve the coronary health status by providing education on a broader basis.

In this secondary analysis within a randomized controlled trial, the aim of our post hoc study was to examine the impact of social, clinical, and psychological factors regarding the social gradient in German CAD patients. The research questions were not pre-specified. They were based on previous experience [1].

Although it has been found that socio-economic characteristics were predictive of health events in Germany as described for other countries [11] little is known about the process that leads to the socio-economic differences and the mechanisms of the SES health gradients. To shed light on this issue we separately examined how standard risk factors, medical prognostic markers, and negative emotions are related to the social gradient in depressed CAD patients from a German multicentre trial.