Differences in disease phenotype and severity in SLE across age groups

Abstract

Objectives: Significant differences have been reported in disease phenotype and severity of systemic lupus erythematosus (SLE) presenting in different age groups. Most indicate a more severe phenotype in juvenile-onset SLE (JSLE). There have been limited studies in older patients and no large studies looking at SLE across all age groups.

Methods: We assessed the effect of age of onset of SLE on the clinical phenotype by analysing data from two large UK cohorts (the UK JSLE Cohort and the UCLH SLE cohort).

Results: A total of 924 individuals were compared (413 JSLE, 511 adult-onset SLE). A female preponderance was present, but less pronounced at either end of the age spectrum. Arthritis was more common with advancing age (93% vs 72%, p < 0.001), whereas renal disease (44% vs 33%, p = 0.001), alopecia (47% vs 23%, p < 0.001) and aphthous ulcerations (39% vs 26%, p = 0.001) were more common in the young. Neuropsychiatric lupus was less common in mature-onset SLE (p < 0.01). JSLE was associated more commonly with thrombocytopenia (21% vs 15%, p = 0.01), haemolytic anaemia (20% vs 3%, p < 0.001), high anti-dsDNA (71% vs 63%, p = 0.009), Sm (22% vs 16%, p = 0.02) and RNP (36% vs 29%, p < 0.04) auto-antibodies. Leucopenia increased with advancing age (p < 0.001). Mortality has been declining over recent decades. However, death rates were substantially higher than the general population. The standardized mortality ratio was 18.3 in JSLE and 3.1 in adult-onset SLE.

Conclusion: These data from the largest-ever direct comparison of JSLE with adult-onset SLE suggest an aggressive phenotype of disease with a worse outcome in patients with JSLE and emphasizes the importance of careful follow-up in this population.

Keywords: Cohort study; childhood-onset SLE; juvenile-onset SLE.

Figure 1

Breakdown of renal involvement by age. The left-hand bars show the breakdown by age as divided into four groups. The right-hand bars summarize key differences between JSLE and adult SLE groups. JSLE: juvenile systemic lupus erythematosus; SLE: systemic lupus erythematosus.

Figure 2

Breakdown of CNS lupus by age. The left-hand bars show the breakdown by age as divided into four groups. The right-hand bars summarize key differences between JSLE and all-adult SLE groups. CNS: central nervous system; JSLE: juvenile systemic lupus erythematosus; SLE: systemic lupus erythematosus.

Figure 3

(a) Mortality rate expressed per 100 patient years, by decade of diagnosis of SLE, showing a reduction of mortality rates over time. (b) Standardized mortality ratio (SMR) of entire cohort by age, grouped into decades, with 90% confidence intervals. Deaths: deaths per 100 patient years; Expected: expected deaths per 100 in England and Wales population; Lower: 90% lower confidence interval; Upper: 90% upper confidence interval; SLE: systemic lupus erythematosus.