AB1387-HPR ASPECTS OF VALIDITY AND RELIABILITY OF THE SWEDISH VERSION OF PATIENT HEALTH QUESTIONNAIRE-8 IN INDIVIDUALS WITH SYSTEMIC SCLEROSIS

Abstract

Background For assessing symptoms of depression in systemic sclerosis (SSc), the Patient Health Questionnaire-8 (PHQ-8) may be useful in clinical care as it is short and easy to administer. The English version of PHQ-8 has been found to be reliable and valid in SSc. Objectives To assess aspects of validity and reliability of PHQ-8 in Swedish (PHQ-8 Swe) for individuals with SSc. Methods Patients meeting the 2013 ACR/EULAR SSc criteria were recruited. The PHQ-8 Swe content validity was assessed via individual interviews (11 patients, 10 healthcare professionals, HPs) which was transcribed and analysed by content analysis. Patients ages, disease durations and symptoms of depression varied. The HPs had different occupational backgrounds and experiences in SSc care. Reliability was tested by internal consistency and test-retest reliability. Sixty-seven patients (median age 62 [minmax: 2887]) completed the PHQ-8 Swe on two different occasions. Results Content validity: The instruction, items, and response options were generally considered easy to understand; however, some clarifications were suggested. Among HPs, it was expressed that some items could be perceived as emotionally demanding for patients especially in recent onset disease. Further they experienced that PHQ-8 was problem- rather than possibility-based. Introducing the PHQ-8 to patients and the need for follow-ups of the answers to the questionnaire were stated as essential. It was further expressed that PHQ-8 covered key aspects of symptoms of depression in SSc nevertheless examples of items suggested to be included were purpose in life, thoughts about death, and loneliness. The items were overall experienced as important without redundancy, and that some items could reflect more general SSc-related symptoms. Cultural adaption: Possible adjustments to the PHQ-8 translation were made. This version was back translated into English and compared with the original English version. Thereafter, minor changes were made. A final PHQ-8 Swe version was tested for reliability. Reliability: Cronbachs alpha was 0.86 and the corrected item-to-total correlation range was 0.420.78. There were no significant differences between testretest for seven of the eight items. The median weighted kappa coefficient was 0.63. The median PHQ-8 Swe total score was 4 (020, no-severe depressive symptoms). There were no significant differences for total scores between test and retest and the ICC was 0.81. Conclusion Content validity of PHQ-8 Swe was satisfactory and a positive quality was indicated for aspects of reliability in individuals with SSc tested in this study. Although some items could be interpreted as covering more general SSc-related symptoms, the PHQ-8 could be valuable for detecting patients with symptoms of depression in need of discussing emotional issues, as reflected in our study. Further studies of the PHQ-8 Swes usefulness are currently being undertaken via evaluation of other psychometric aspects.