WASHINGTON — Patients with systemic lupus erythematosus improved their 10-year survival rates during a 41-year period despite demographic changes, according to data presented at the American College of Rheumatology Annual Meeting.
Researchers in Boston studied 1,099 patients with systemic lupus erythematosus (SLE) who were part of a lupus registry. Age at SLE diagnosis, history of lupus nephritis, serologies, hematology and renal laboratories, medication use and date of death were gathered from medical records. Patients were followed for 10 years, until death or until April 30, 2011 when follow-up ended. To estimate the risk for death over time and to investigate potential mortality predictors, researchers used Kaplan-Meier survival curves with log rank tests and multivariable Cox proportional hazards models, adjusted for age at diagnosis, race, sex, nephritis and hydroxychloroquine use.
Joseph F. Merola
Based on equal person-time (54,000 person-months), patients were divided into two groups: Jan. 1, 1970-Aug. 31, 1993 (70% women) and Sept. 1, 1993-April 30, 2011 (53% men). All patients were antinuclear antibodies positive, with approximately 60% anti-dsDNA antibodies positive. Of the more recently diagnosed patients, more were non-white (62.8% white, early time group vs. 40.5%, later time group; P<.001), had an older mean age at SLE diagnosis (29.4 years vs. 36.0 years; P<.001) and were prescribed hydroxychloroquine (75.3% vs. 86.6%; P<.001). Patients were followed up for a mean of 8.8 years.
Seventy patients died during the first time period compared with 28 during the second frame (10-year survival, 84.5% for earlier time period vs. 95% for later time period; log rank test, P=.01). Among patients diagnosed in the later period compared with earlier diagnoses, multivariable analysis showed 10-year mortality of HR=0.47 (95% CI, 0.29-0.75), which increased with older age at diagnosis (HR=1.05; 95% CI, 1.03-1.07) and male gender (HR=2.36; 95% CI, 1.32-4.20). Survival during the time period showed no significant association between hydroxychloroquine use, race or nephritis.
“This further supports some other recent work … that survival has improved among these lupus cohorts,” researcher Joseph F. Merola, MD, instructor in the dermatology department at Harvard Medical School and a fellow in the division of rheumatology at Brigham and Women’s Hospital, told Healio.com. “It’s interesting that it’s not associated with [factors including] nephritis, which was expected to be the reason why.
“We’re talking about a pretty significant improvement in survival over this time period,” he said. “The question it doesn’t answer, and we’re going to hope to look for in a little more detail next, is the ‘why.’ … That would be the obvious next step.”
For more information:
Merola JF. P937: Changes in Ten Year Survival Among SLE Patients At an Academic Center in North America (1970-2011). Presented at: American College of Rheumatology 2012 Annual Meeting; Nov. 10-14, Washington.