Introduction Evidence suggests that psychological factors, such as depression and anxiety, are independent risk factors for increased morbidity and mortality post ST-elevation myocardial infarction (STEMI). Since improved treatments have increased survival rates post STEMI the emphasis has turned to more patient related outcome measures such as health-related quality of life (HRQoL). The aim of the study was to assess the contribution of anxiety and depression to HRQoL in post STEMI patients, after controlling for possible confounding factors, including type of treatment.

Methods We conducted a prospective cohort study of 385 post-STEMI patients who had undergone either lysis (183) or PPCI (202). The mean age was 60.0 years (SD 11.8) and 78% were male. Patients were assessed on a range of demographic, clinical and psychosocial variables, including measures of cardiac risk, cardiac severity and comorbidity (Charlson Comorbidity Index—CCI). Psychosocial assessment included anxiety and depression (Hospital Anxiety and Depression Scale), illness perceptions (brief IPQ), and health-related quality of life (SF-36). The main outcome was the SF-36 Physical Component Score (PCS) at 6 months post-STEMI.

Results Baseline results revealed a small number significant differences between groups on a range of clinical variables, including higher GRACE scores for PPCI group (p=0.007) but no differences in LV function. Lysis patients had more comorbid illness as measured by the CCI (p=0.037). Regarding psychological variables the total HADS score was significantly higher in the PPCI vs lysis group at baseline (means 13.2 (SD 7.9) and 11.4 (SD 8.9), p=0.035), while anxiety and depression almost reached significance, with raised anxiety and depression scores in the PPCI group. In order to identify variables at baseline that may contribute to SF-36 PCS at 6 months, we conducted a hierarchical multiple regression with four blocks of independent variables—demographic, comorbidity-related, clinical and psychological. Factors which contributed to the final model were cholesterol levels (p=0.031) and depression (p<0.001). Treatment group did not play a role (p=0.199). The addition of anxiety and depression contributed significantly to the reporting of lower physical health-related quality of life (PCS) at 6 months (ÄR2=0.12, p<0.001).

Conclusion The findings have shown that raised levels of depression and anxiety predicted impairment in health-related quality of life at 6 months post-STEMI, regardless of mode of treatment. The results indicate that the assessment of psychological factors is important in both groups. Despite PPCI having improved clinical outcomes, there will always be a group of patients receiving lysis. As such it is important to assess anxiety and depression in post STEMI patients, and to include these potentially modifiable factors in the design of suitable interventions for this patient group.