MANCHESTER, U.K. (FRONTLINE MEDICAL NEWS)When systemic lupus erythematosus (SLE) occurs before age 40, patients run a high relative risk of end-stage renal disease, data from a retrospective U.K.-based cohort study have shown.

While the risk for cardiovascular disease and stroke has been reported previously, particularly in younger SLE patients, the risks for comorbidities such as end-stage renal failure (ESRF), osteoporosis, and infection were not as clear. “We know that comorbidities are increased in patients with lupus, but we didn’t know by how much,” Dr. Frances Rees of Nottingham University Hospitals NHS Trust, Nottingham, England, explained at the British Society for Rheumatology annual conference.The adjusted incidence rate ratio (IRR) for ESRF was greater than 60 for lupus patients under age 40 and about 10 for those aged 40-69 years.“Although the absolute risk increased with age, the relative risk difference between cases and controls was highest in those at younger ages, so don’t forget primary prevention and screening in younger patients,” Dr. Rees said.

The risk was based on data obtained from the Clinical Practice Research Datalink , an anonymized database of primary care records for approximately 12 million people, on all prevalent cases of SLE occurring between 1999 and 2012 in the United Kingdom. Each of the 7,732 cases was matched to up to four patients who did not have lupus and were seen at the same practice. The control population exceeded 28,000 individuals.

Around 55% of lupus patients had a Charlson Comorbidity Index (CCI) of zero while around 75% of patients without lupus had no comorbidities. About 33% of lupus patients had a CCI of 1-2 as did about 20% of controls; less than 10% of patients had a CCI of 3-5 or more than 5.

“The highest difference between the two groups was for end-stage renal failure even after adjusting for confounders,” she added. IRRs for the other comorbidities were around or just under 2.“When we compared men and women, men had higher risks of cardiovascular disease, stroke, and cancer, but women had higher rates of infection and osteoporosis, which would fit with the underlying population,” Dr. Rees observed.

“What was interesting, however, was the difference in the incidence rates for osteoporosis between cases and controls in men, which was of a bigger relative risk than it was in women,” Dr. Rees noted. “So don’t forget to consider osteoporosis in men,” she advised. For cardiovascular disease, the IRR was much higher in patients under age 40 years than for the older patients (IRR <5).In an interview, Dr. Rees explained that while these data partly confirm what was already known, the research is the first to look at comorbidity in SLE from a community perspective. “Also, some of the previous studies done in hospitals have only really shown that the risk of cardiovascular disease and stroke was in younger people, but we have found that the risk was increased across all age groups.”

The work was supported by a research grant from Lupus UK. Dr. Rees had no conflicts of interest.

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