LATE-ONSET SYSTEMIC LUPUS-ERYTHEMATOSUS IN SOUTHERN CHINESE

Objective-Systemic lupus erythematosus (SLE) is a multisystem disorder that predominately affects women of the reproductive age. Onset of th e disease beyond the age of 50 years is unusual. This study was undert aken to compare retrospectively the clinical and laboratory features b etween early and late onset (onset of disease beyond the age of 50 yea rs) SLE patients in a Chinese population. Methods-Case records of all SLE patients who attended our rheumatology clinics between 1971 and 19 97 were reviewed. Patients with a disease onset beyond the age of 50 y ears were identified. One hundred consecutive SLE patients who had the ir disease onset before the age of 50 were recruited as controls. The presenting clinical features, autoantibody profile, number of major or gans involved, number of major relapses, and the use of cytotoxic agen ts in the two groups of patients were obtained and compared. Results-2 5 patients with late onset SLE were identified. All the female patient s in the late onset group were postmenopausal. The female to male rati o was 3.2 to 1, compared with 13.3 to 1 in the control group (p<0.02). Both groups had a comparable duration of disease. There were no signi ficant differences in the presenting features between the two groups e xcept for a lower prevalence of malar rash (24% v 86%, p<0.0001) and a higher prevalence of rheumatoid factor (32% v 1%, p<0.0001) in the la te onset patients. On subsequent visits, the late onset group had a lo wer prevalence of lupus nephritis (4% v 51%, p<0.001), fewer major org ans involved (mean number of major organs involved; 0.3 v 0.9, p<0.02) , fewer major relapses (mean number of major relapses/patient; 0.08 v 0.47, p<0.002, number of major relapses/patient year; 0.009 v 0.12, p< 0.001), and required fewer cytotoxic agents for disease control (perce ntage of patients on cytotoxic agents; 32% v 79%, p<0.002). Conclusion -Late onset SLE in Chinese tends to run a more benign course with fewe r major organ involvement and fewer major relapses. The significantly higher incidence of male sex in late onset SLE and the milder disease course in the postmenopausal female patients suggest that oestrogen st atus may influence disease activity.