Time-dependent depression and anxiety symptoms as risk factors for recurrent cardiac events: findings from the UPBEAT-UK study

Background Depression is a well-known risk factor for recurrent cardiac events (RCEs) but findings are less consistent for anxiety, not previously reported on using a time-dependent approach. We aimed to study the prognostic effect of anxiety and depression symptom levels on RCEs. Methods Data (N = 595) were drawn from the UPBEAT-UK heart disease patient cohort with 6-monthly follow-ups over 3 years. Hospital Anxiety and Depression Scale symptoms were grouped into: agitation (three items), anxiety (four items), and depression (seven items) subscales. We performed two types of multivariate analyses using Cox proportional hazard models with delayed entry: with baseline variables (long-term analysis), and with variables measured 12-to-18 months prior to the event (short-term time-dependent analysis), as RCE risk factors. Results In the baseline analysis, both anxiety and depression, but not agitation, were separate RCE risk factors, with a moderating effect when considered jointly. In the short-term time-dependent analysis, elevated scores on the anxiety subscale were associated with increased RCE risk even when adjusted for depression [hazard ratio (95% confidence interval) 1.22 (1.05-1.41), p = 0.009]. Depression was no longer a significant predictor when adjusted for anxiety [1.05 (0.87-1.27), p = 0.61]. For anxiety, individual items associated with RCEs differed between the two approaches: item 5 'worrying thoughts' was the most significant long-term risk factor [1.52 (1.21-1.91), p = 0.0004] whereas item 13 'feelings of panic' was the most significant time-dependent short-term risk factor [1.52 (1.18-1.95), p = 0.001]. Conclusions Anxiety is an important short-term preventable and potentially causal risk factor for RCEs, to be targeted in secondary cardiac disease prevention programmes.