Direct healthcare costs and predictors of costs in patients with primary Sjögren's syndrome

Objectives. To analyse the healthcare usage, direct healthcare costs and predictors of cost in primary Sjögren's syndrome (PSS) in the UK and to compare the findings with the data from healthy control groups and rheumatoid arthritis (RA) patients. Methods. A total of 129 patients with PSS (American-European criteria), 91 with RA and 92 controls, were included in the study. All groups were age-matched females and all completed questionnaires on health status (SF-36) and healthcare utilization (economic component of the Stanford Health Assessment Questionnaire). Annual direct healthcare costs were calculated (and expressed in 2004 UK pound sterling) and predictors of costs for each patient group were determined by regression analyses. Age, health status, disease duration and anti-Ro/La antibody positivity were used as potential predictor variables. Results. Mean age was similar in the PSS (59.2 yrs, s.d. 11.6), RA (60.3 yrs, s.d. 10.5) and control groups (57.7 yrs, s.d. 12.5). The mean disease duration was 5.4 yrs (s.d. 4.8) in the PSS group and 13.4 yrs (s.d. 11.4) in the RA group. The mean annual total direct cost per patient [95% confidence interval (CI)] was £2188 (£1831 and £2546) in the PSS group, £2693 (£2069 and £3428) in the RA group and £949 (£741 and £1156) in the control group. The costs in the PSS group were greater than for the RA and control groups for visits to all healthcare professionals (total) as well as visits to the dentist, dental hospital and ophthalmologist. The costs in the PSS and RA groups were higher than in controls for diagnostic tests and visits to hospital and the accident and emergency (A&E) department. The PSS group also incurred higher costs than controls, but lower costs than the RA group, for visits to a rheumatologist, urine and blood tests, assistive devices and drug therapy. Regression analysis identified the SF-36 physical function subscale as the best predictor of costs in PSS patients as well as controls and the mental health subscale in RA patients. Conclusion. This is the first study to evaluate direct healthcare costs in patients with PSS. PSS has a significant impact on the healthcare system, similar to that of RA, by more than doubling costs compared with control patients.