To date, few data have been published on uveitis prevalence among children and adolescents with spondyloarthritis. Herein we report ocular manifestations in a large cohort of JSpA patients. The prevalence of uveitis was 11%, the rate of HLA-B27 positivity of 38%, and the majority of patients had symptomatic uveitis (79%). Those patients with HLA-B27 positivity were neither more likely to have uveitis, nor symptomatic uveitis, than were other patients.
Current knowledge on uveitis in JSpA patients has been abstracted from adults with SpA and JIA associated uveitis. Indeed, the previous reported JSpA cohorts are small and analysis does not focus on ocular inflammation. Two recently published JSpA cohorts, one from France (114 patients) and one from Germany (118 patients) shared similar features: ERA patients as the prevalent subset (69% and 52%), male predominance (63% and 73%) and a rate of HLA-B27 positivity ranging from 43% and 66% [6, 7]. Data on uveitis were provided just in the German cohort: the uveitis rate was 7%, without further description of associated characteristics [6].
Similarly to these cohorts, the ERA subset was the most represented in our cohort (60%).
The high rate of PsA patients in our cohort (18%) may explain the absence of male prevalence and the lower rate of HLA-B27 positivity compared to the other cohorts [6, 7]. This may also contribute to the higher rate of uveitis in our cohort compared to the German JSpA cohort (11% vs 7%).
Focusing on ocular manifestations, studies in the German and Canadian registries examined the prevalence and presentation of uveitis in different JIA subtypes [8, 9]. The uveitis prevalence in the PsA subset in our study was comparable to those in the two registries (7% in our study and 10% in both German and Canadian registries). Whereas in our study, the ERA subcohort had a higher percentage of uveitis than in the Canadian and German registries (13% vs 8% and 7%, respectively), and the UA subcohort had a higher percentage than the Canadian but not German registries (7% vs 1% and 7%, respectively) [8, 9]. Amongst ERA patients, the rate of symptomatic uveitis in our cohort was higher than in the German registry (83% vs 67%), but the rate of HLA-B27 positivity among ERA patients with uveitis was lower than in the German cohort (44% vs. 75%) [9]. No information regarding symptoms related to uveitis and HLA-B27 prevalence were available in the Canadian registry [8].
Comparing our results to what is described in adult SpA, we identified a lower prevalence of uveitis. About one-third of SpA patients develop uveitis [3, 4], whereas in our cohort, the uveitis prevalence was 11%. Similarly to SpA, JSpA patients were more likely to develop symptomatic rather than asymptomatic uveitis. While the prevalence of uveitis is significantly higher in HLA-B27 positive, than in HLA-B27 negative, adults [4], that was not the case in our cohort.
This observational study has some limitations. As patients must consent to inclusion, this study only approximates the prevalence of uveitis in JSpA patients. There may have been selection bias due to differential consent amongst patients with different underlying diagnoses. Another limitation is the dependence on patient recall of symptomaticity of uveitis rather than determination from chart review of individual ophthalmologic visits. This could result in either under or over-reporting of symptoms, but there is little reason to suspect that this would vary amongst patients of different underlying diagnoses. Missingness of data on HLA-B27 status was another limitation. While it was relatively high in the IBD population and might impact determination of the association of HLA-B27 with uveitis and symptomaticity in these patients, it was quite low in the ERA subcohort.
In conclusion, we have described characteristics of uveitis in a large cohort of JSpA patients. The prevalence of uveitis was lower than hypothesized and than has been reported in adult SpA patients. About one tenth of patients developed uveitis. Fewer than half of the patients with uveitis were HLA-B27 positive. As expected, the majority reported ocular symptoms along with uveitis. Finally, in this cohort, HLA-B27 status was not associated with either the development, or with symptomaticity, of uveitis.