International validation of the Distress Thermometer: State of the science (#285)
Aims: There is increasing international interest in the routine screening of cancer patients for distress. Routine screening to identify clinically significant distress, on an international scale, involves translating, testing, and validating existing instruments in cancer patients in different countries and cultures. We conducted a review of the Distress Thermometer (DT), a widely used single-item instrument first published in English in 1998 and designed to rapidly screen for distress in cancer patients, to gauge international validation of the DT.
Methods: In early 2012 electronic searches of English language databases were conducted and an electronic mail survey was sent to members of the International Psychosocial Oncology Society Federation, considered representative of world-wide psycho-oncology care and research.
Results: Our efforts yielded 19 different language versions of the DT. Numerous approaches were used to translate the instrument from English into the target language. Validation studies were conducted in 25 different countries (sample size range = 100 to 574 patients). Nearly all studies were conducted with mixed cancer types. Samples largely consisted of patients across the care continuum; for example, patients in active treatment were often combined with patients who had completed treatment. A variety of instruments were used in receiver operating characteristic curve analysis to derive an optimal cut-off score indicating clinically significant distress; the Hospital Anxiety and Depression Scale was the most commonly used criterion. Cut-off scores ranged from 2 to 7 and varied by language, country, and clinical setting, and in relation to sample characteristics. In most studies a score of 4 maximized sensitivity and specificity relative to an established criterion.
Conclusions: These findings provide a broad, international perspective on the current state of psychosocial screening using the DT. Findings also evidence the widespread awareness of the need for psychological and social support of persons diagnosed with and treated for cancer.