Cross-cultural adaptation of the Type D Personality Scale for use with patients diagnosed with Ischemic Heart Disease in Sri Lanka.

Introduction: Ischemic Heart Disease (IHD), a major cardiovascular disease globally, has become the primary cause of death in Sri Lanka. Negative affectivity (NA) and social inhibition (SI) are two personality traits which increase the risk of IHD. The Type D Scale (DS-14) evaluates a person's general level of distress on NA and SI. However, DS-14 has not been translated and validated into Sinhala in Sri Lanka.

Objectives: The study aimed to cross-culturally adapt and validate the DS-14 for use with Sinhala speaking patients diagnosed with IHD.

Methods: Translation, back translation and pre-test were conducted before a two-rounds of a Delphi process which assessed content and consensual validity of the instrument. The validated questionnaires were administered to 140 patients diagnosed with IHD at a Base Hospital. Factor structure was confirmed through Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA) and reliability, by internal consistency with Cronbach's alpha.

Results: The questionnaire was administered among 140 participants (85 females), aged 18-60 years. The DS-14 Sinhala version showed good content and consensual validity. Factor analysis proved two factors compatible with the original instrument, which explained the variance of 62.9%. CFA confirmed the two-factor model. The reliability analysis indicated Cronbach's alpha for NA and SI as 0.93 and 0.88, respectively.

Conclusion: The cross-culturally adapted DS-14 Sinhala version indicated the same psychometric properties as the original instrument, in the local context with IHD patients. It can be confidently applied in the investigation of Type D personality in IHD prevention and treatment, as well as in research.