The Quality of Life Research Journal, A-21, Abstract #1197.
Oral presentation at 14th annual ISOQOL conference in Toronto 10-13.10.2007
AIMS To develop the 13-item RetTSQ, a measure of satisfaction with treatment for diabetic retinopathy (DR). Modelled on the widely used Diabetes Treatment Satisfaction Questionnaire, the RetTSQ was designed in English and German with the aid of 44 in-depth interviews with people with DR, including 31 with macular oedema.
METHODS Data from 207 German patients with DR were analysed. Principal components analysis (PCA) explored factor structure. Internal consistency reliability was assessed using Cronbach’s alpha. Construct validity was investigated by testing expected relationships of RetTSQ scores with visual impairment, stage of DR (ranging from mild non-proliferative to proliferative), the additional effect of macular oedema and SF-12 subscales. Content validity was explored using answers to an open-ended question asking for any other sources of satisfaction or dissatisfaction.
RESULTS PCA indicated two subscales, one representing negative treatment experiences like side effects, discomfort or pain; the second covering positive aspects like safety and efficacy. A total score can be calculated. Reliabilities were high with alpha=0.90 for the total score and alpha=0.86 and 0.84 for the subscales. The worse the visual impairment, the less satisfied patients were with treatment (F(4,166)=13.39, p<0.001). Non-proliferative DR was associated with higher treatment satisfaction than proliferative (t=2.92, p<0.01). Patients with macular oedema were less satisfied than those without (F(1,184)=11.35, p<0.01). RetTSQ total score correlated significantly but not highly with SF-12 subscales (physical r=0.38, mental r=0.52, both p<0.01). Results for RetTSQ subscales showed patterns similar to the total score with some indication that subscale 1 showed more sensitivity to sex differences and stage of DR. Other demographic variables were unrelated to RetTSQ scores. Answers to the open-ended question (n=15) mainly emphasised existing items such as after effects.
CONCLUSIONS The RetTSQ is a reliable and valid measure giving a comprehensive picture of satisfaction with treatment for diabetic retinopathy with or without macular oedema.
