Impaired health-related quality of life in Addison's disease--impact of replacement therapy, comorbidities and socio-economic factors.

OBJECTIVE: Patients with Addison's disease (AD) on conventional replacement therapy have impaired health-related quality of life (HRQoL). It is possible that lower hydrocortisone (HC) doses recommended by current guidelines could restore HRQoL. We compared HRQoL in AD patients treated according to current HC recommendations to that of the age- and gender-standardized general population. SUBJECTS, DESIGN AND MEASUREMENT: We assessed HRQoL in a cross-sectional setting with the 15D instrument in a Finnish AD cohort (n = 107) and compared the results with those of a large sample of general population (n = 5671). We examined possible predictors of HRQoL in AD. Within the patient group, HRQoL was also assessed by SF-36.
RESULTS: Mean HC dose was 22 mg/d, corresponding to 12 ± 4 mg/m2. HRQoL was impaired in AD compared with the general population (15D score; 0·853 vs 0·918, P < 0·001). Within single 15D dimensions, discomfort and symptoms, vitality and sexual activity were most affected. Stepwise regression analysis demonstrated that Patient's Association membership (P = 0·02), female gender (P < 0·01), presence of other autoimmune or inflammatory comorbidity (P < 0·02), lower education (P < 0·02) and longer disease duration (P < 0·05) independently predicted impaired HRQoL, whereas replacement regimens, autoimmune-related comorbidities, total number of comorbidities or level of healthcare follow-up did not. In AD, HRQoL was impaired also as assessed by SF-36.
CONCLUSIONS: HRQoL is significantly impaired in AD compared with the general population despite use of recommended HC doses. Patient's Association membership was the most significant predictor of impaired HRQoL. This finding should be explored in more detail in the future.