Patterns of Ambulatory Medical Care Utilization and Rheumatologist Consultation Predating the Diagnosis of Systemic Lupus Erythematosus: A National Population-Based Study

OBJECTIVE: To investigate the records of ambulatory medical care from patients predating the diagnosis of systemic lupus erythematosus (SLE) using nationwide, population-based claims data. METHODS: The frequencies and costs of ambulatory medical care utilization in 337 newly-diagnosed SLE cases between 2004 and 2010, identified from Taiwan's National Health Insurance Research Database, were compared with 1,348 controls who were frequency matched for sex, age, and the catastrophic illness certificate application year of the cases. RESULTS: Patients with SLE had a median frequency of ambulatory medical care utilization compared with controls one year prior to the index date (22 vs. 2, P<0.001). The differences were significant throughout all eight annual periods. Similarly, the inflation-adjusted costs of ambulatory medical care utilization in patients with SLE increased annually over the study period, from a median of US$18 eight years prior to the index date to US$680 one year prior to the index date. Diseases of the respiratory system (International Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9-CM] codes 460–519), digestive system (ICD-9-CM codes 520–579), musculoskeletal system and connective tissue (ICD-9-CM codes 710–739, excluding 710.0), and skin and subcutaneous tissue (ICD-9-CM codes 680–709) were the top four common causes of visits in the 0.5 to 2 year period preceding the index date and percentages of SLE patients suffered from these disorders increased progressively over the study period. Only 56.4% of the patients with SLE had consulted a rheumatologist and most of the serology tests were done within one year predating the index date. CONCLUSIONS: Increased frequencies and costs of ambulatory care utilization among Taiwanese patients with SLE occurred several years predating their definitive SLE diagnosis. When multisystemic disorders are presented in young female patients, the possibility of SLE should be considered and screened with tools such as the antinuclear antibody test.