Explaining heterogeneity in the predictive value of Type D personality for cardiac events and mortality

Background
Type D personality has been associated with adverse outcomes in patients with coronary artery disease (CAD). However, large heterogeneity exists between Type D studies, including some studies reporting null-findings.
Objectives
The aim of this study was to examine i) choice of endpoint and ii) age as two study characteristics that may partly explain this large heterogeneity in the Type D associated prognostic effect.
Methods
We used four existing data cohorts of 1503 CAD patients (89% male, mean age = 57.2 ± 9.1) with baseline measures of Type D and endpoints > 5 years follow-up: major adverse cardiac events (MACE), cardiac death/MI, and non-cardiac death. Patients were classified in 4 age categories: < 50 y, 50–59 y, 60–69 y and ≥ 70 y. Multiple logistic regression models included age, sex, and clinical covariates.
Results
At follow-up, there were 295 events, including 116 cardiac death/MI, and 37 non-cardiac deaths. Both continuous and categorical measures of Type D predicted adverse events. Type D was independently associated with MACE (OR = 1.82; 95%CI 1.33–2.50) and cardiac death/MI (OR = 2.49; 95%CI 1.55–3.99). However, Type D was not associated with non-cardiac death (OR = 1.23; 95%CI 0.57–2.69). Regarding age, Type D consistently predicted MACE in the lower age groups (all ORs ≥ 2.20, all ps ≤ .004), but not in patients aged ≥ 70 y (OR = 1.43, p = .57).
Conclusions
Choice of endpoint and age modulated the risk conferred by Type D personality. Type D was associated with an increased risk of cardiac events, but not with non-cardiac death, or with events in patients aged ≥ 70 y. Research on psychosocial risk in CAD should account for different sources of heterogeneity in study characteristics.