Trends in annual costs of ambulatory medical care utilization over an eight-year period preceding the index date.

Estimates were adjusted for age, sex and Charlson Comorbidity Index using generalized estimating equation with log link function and gamma distribution. Costs were converted to US dollars based on annual exchange rates and adjusted to 2010 figures based on Taiwan's consumer price index.
SLE, systemic lupus erythematosus; 95% CI, 95% confidence interval.