Patients with mild to moderate systemic lupus erythematosus (SLE) disease activity without any past history of organ damage may still progress to develop damage, particularly renal and cardiovascular disease, or death, in a relatively short amount of follow-up time, new research suggests.
The study, published in Lupus Science & Medicine, also showed that use of hydroxychloroquine lowered the risk of death and renal damage, whereas use of NSAIDs or any antihypertensives increased risk for cardiovascular damage.
“The impact of irreversible organ system damage in the prognosis of SLE remains a major concern because patients who develop damage are more likely to accrue additional damage and die,” wrote Deanna Hill, PhD, of GlaxoSmithKline, Collegeville, Pa., and coauthors, including Michelle Petri, MD, of Johns Hopkins University, Baltimore.
The researchers followed 1,168 adult patients with SLE from the Johns Hopkins Lupus Cohort, most of whom were women, 55% of whom were White and 39% of whom were Black. They divided the follow-up period into three parts: first year after enrollment into the cohort as background, second year as observation period, and the remainder of follow-up time until damage occurred, death, or end of available data.
At baseline, 55% of patients had mild to moderate disease, defined as an adjusted mean SELENA-SLEDAI (Safety of Estrogens in Lupus Erythematosus National Assessment SLE Disease Activity Index) score of less than 3. Patients had a median adjusted mean SELENA-SLEDAI score of 3 in the first year, which dropped to 2 in the observation period and remained there during the rest of follow-up.
Eight percent of patients died during the follow-up period. Each one-unit mean increase in SELENA-SLEDAI score during the 1-year observation period was associated with a significant 22% increase in the subsequent risk of death during the subsequent follow-up period (95% confidence interval, 1.13-1.32; P < .001).
Three-quarters of patients (n = 888) had no history of damage at the start of the follow-up period, but 39% of these patients had developed damage by the end of follow-up. Among patients without prior damage, a single-unit increase in disease activity score was also associated with a 9% increase in the risk of accruing organ damage (95% CI, 1.04-1.15; P < .001) after adjustment for confounding factors.
While only 3% of patients – most of whom were women – developed renal damage during the follow-up period, a one-unit increase in disease activity score was associated with a 24% increase in the risk of renal damage (95% CI, 1.08-1.42, P = .003).
The researchers found that 7% of patients developed cardiovascular damage during the follow-up period, and each one-unit increase in disease activity score was associated with a 17% increase in the risk of cardiovascular damage (95% CI, 1.07-1.29; P < .001).
“The findings in this analysis corroborate the influence of disease activity for renal and cardiovascular damage accrual and death and also extend the findings to patients with SLE and mild to moderate disease activity,” the authors wrote.
Impact of treatment
Researchers also examined the effect of treatments, and found that patients treated with hydroxychloroquine during the 1-year observation period had a 54% lower risk of subsequent death (95% CI, 0.29-0.72; P < .05) and a 70% lower risk of renal damage (95% CI, 0.13-0.68, P < .05). However, patients prescribed NSAIDs had a 66% higher risk of cardiovascular damage, while those who used any antihypertensive had an 81% higher risk of cardiovascular damage.
“This may suggest that the known cardiovascular risk of NSAIDs in the general population is also applicable to patients with SLE and highlights the importance of assessing cardiovascular risk in this patient population,” the authors wrote.
Smoking affected the risk of death: Smokers were 74% more likely to die during the follow-up period than were nonsmokers.
There were no significant differences between different ethnicities in the study. While White patients generally had lower disease activity overall, there was no significant differences in the risk of death or organ damage with ethnicity.
The Hopkins Lupus Cohort is supported by the National Institutes of Health, and the study was funded by GlaxoSmithKline. Three authors were paid employees of GlaxoSmithKline and two were paid consultants or contractors.