The Big Mush: Psychometric Measures are Confounded and Non-Independent in Their Association with Age at Initial Diagnosis of Ischaemic Coronary Heart Disease

Abstract

The present study uses early diagnosis of ischaemic coronary heart disease (ICHD) as a proxy for disease malignancy in testing the statistical strength of association, and uniqueness/confounding, of several psychometric scales that have previously been found to prospectively predict death in cardiac samples (Beck Depression Inventory, Crown–Crisp Phobic Anxiety Scale, Type D Scale & Ketterer Stress Symptom Frequency Checklist). Eighty-three patients (no. of females=35) with documented ICHD were assessed for traditional and psychometric risk factors. The psychometric risk factors were moderately to strongly intercorrelated, and strongly confounded in their relationship to age at initial diagnosis. In a stepwise multiple regression, only the AIAI (aggravation, irritation, anger and impatience) scale of the Ketterer Stress Symptom Frequency Checklist (KSSFC) survived as a predictor of age at initial diagnosis (P=0.016). In a subgroup of the sample for whom the Spouse/Friend Version of the KSSFC was received (n=58, or 70%), spouse/friend reported AIAI survived as the only predictor (P=0.010). While present results need replication in a prospective study of diagnosed ICHD patients for all important clinical outcomes, only one psychometric screening instrument may be necessary to identify patients in need of treatment.