A French nationwide study found that patients with systemic lupus erythematosus (SLE) who had chronic kidney disease were at increased risk for poor outcomes, including end-stage kidney disease and death.
According to a multivariate analysis, the risk index for end-stage kidney disease among patients with chronic kidney disease at the start of the study was 15.9 (95% CI 11.6-21.9, P <0.0001), according to Karim Sacre, MD, and colleagues from the University of Paris. Diderot.
“Impaired kidney function in the diagnosis of lupus nephritis and the inability to normalize kidney function with aggressive immunosuppressive therapy are associated with very poor long-term kidney outcome,” the team explained.
Approximately half of SLE patients develop nephritis, which is characterized by deposits of glomerular immune complexes of immunoglobulin (Ig) M, IgG, and IgA. Progression to end-stage kidney disease is generally expected in up to 30% of patients within 15 years of diagnosis of lupus nephritis.
However, most reports of lupus nephritis outcomes have been limited by the small sample size and come from specialized care facilities. Therefore, to provide a more complete picture, Sacre’s group analyzed data from the national administrative database, including 6,439 SLE patients who enrolled in 2009 and were followed up until 2015.
Chronic kidney disease was defined as an estimated glomerular filtration rate below 60 ml / min / 1.73 m 2 .
The mean age of the patients was 46 years and the majority were women. A total of 428 (6.7%) had chronic kidney disease at the start of the study.
From 2009 to 2015, 10.1% of patients without chronic kidney disease at the start of the study developed the disease, and 33.15% of those with chronic kidney disease at the start of the study switched to end-stage renal disease.
The very high risk of developing end-stage kidney disease in this cohort requiring kidney transplantation or chronic dialysis confirms previous studies showing that kidney failure is an important predictor of morbidity in SLE, Sacre and its authors said. Additionally, data on other factors that could further increase risk, such as findings from kidney biopsy, urinary protein production, and ethnicity, were not available in the national database.
In a univariate analysis, factors that were associated with chronic kidney disease included the following:
- Sexo masculino (OR 1.7, IC 95% 1.3-2.1, P = 0.0002)
- Hipertensión (OR 3.4, IC 95% 2.7-4.2, P <0.0001)
- Choque séptico (OR 4.1, IC 95% 2.3-7.3)
- History of cardiovascular disease (OR 3.4, 95% CI 2.7-4.2)
In the multivariate analysis, additional strong and independent associations were observed for cardiovascular events (HR 1.7, 95% CI 1.4-2.2, P <0.0001), as well as septic shock (HR 2.1, 95% CI 1.5-2.8, P <0.0017 ).
Cardiovascular events associated with atherosclerosis remain the leading cause of death in SLE. According to the researchers, conventional risk prediction models, such as the Framingham score, underestimate the risks in SLE. “Our study highlights the strong association between chronic kidney disease and cardiovascular events in SLE and supports drastic primary prevention of cardiovascular disease in SLE patients with chronic kidney disease,” the team wrote.
The researchers added that another major concern for SLE patients is the development of a serious infection, which can lead to both morbidity and mortality. For example, a previous study reported high rates of pneumococcal infections in SLE patients with nephritis, and another recent study found that approximately one in 10 cases of septic shock were caused by organisms preventable by vaccination. “Therefore, our study also points to the need for optimal vaccination coverage in SLE with chronic kidney disease,” Sacre and colleagues observed.
A limitation of the study, the researchers said, was its reliance only on hospital data, so the results may have been underestimated.
“Our results illustrate the critical importance of early detection (that is, before the onset of impaired kidney function) and treatment of lupus nephritis,” the researchers concluded.