Systemic lupus erythematosus (SLE) is a multisystem inflammatory disease predominantly occurring in females of childbearing age. Late onset SLE patients are uncommon and have different clinical and laboratory characteristics compared with younger patients. Methods: For further investigation of this subgroup, we retrospectively reviewed and analyzed 19 SLE patients with disease onset at age 60 years or older (Group A) collected from 1998 to 2008 in the computerized database of outpatients and

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... atients of our hospital. For comparison, 50 SLE patients with disease onset between 15 and 40 years (Group B) were also selected using a simple random sampling method during the same period from the same database. Results: When compared with Group B, Group A had: (1) a decreased ratio of female to male; (2) a longer lag time from disease onset to diagnosis; (3) higher rates of renal insufficiency and mortality; and (4) lower immunologic disorder rates, including anti-double-stranded DNA antibody, anti-ribonucleoprotein antibody and hypocomplementemia. The main cause of death in both groups was septic shock. Conclusion: The clinical and laboratory features were found to be different between Groups A and B. Late onset SLE patients had a more insidious onset, a longer lag time from disease onset to diagnosis and, therefore, a higher mortality rate. Thus, this particular subgroup of SLE patients should be afforded greater attention to avoid delays in diagnosis or misdiagnosis.