First author : G Karatemiz
Review : Rheumatology
Reference : DOI : doi.org/10.1093/rheumatology/keac223
Link to article https://academic.oup.com/rheumatology/article/62/1/9/6601421
Introduction:
Inflammatory rheumatic diseases are a classic cause of inflammatory amyloidosis (AA). Behçet's disease is a multi-systemic vasculitis that affects vessels of all calibres. Although uncommon in Behçet's disease, AA amyloidosis is at high risk of mortality and is one of the main causes of renal failure in Behçet's disease. The authors' aim was to determine the frequency of AA amyloidosis in patients with Behçet's disease, and identify clinical and therapeutic demographics.
Methods:
Patients with Behçet's disease complicating with AA amyloidosis in Turkey were included. The primary endpoints were end-stage renal disease and death. The prevalence of AA amyloidosis was estimated separately for patients registered between 1976 and 2000 and those registered between 2001 and 2017, to determine whether there was a change in frequency.
A systematic review of the literature on cases of AA amyloidosis complicating Behçet's disease accompanied this study.
Results:
Between 1976 and 2017, a cohort of patients with Behçet's disease (n=9410) was followed of whom, 27 (0.29%) developed AA amyloidosis.
Between 1976 and 2000, a cohort of 3,820 patients with Behçet's disease was followed; 24 patients (0.62%) developed AA amyloidosis.
Between 2001 and 2017, of the 5590 patients followed for Behçet's disease, 3 developed AA amyloidosis (0.054%).
The incidence of AA amyloidosis increased from 0.62% to 0.054% (P < 0.0001).
Co-morbidities that may be associated with amyloidosis were tuberculosis (n= 2), FMF
FMF (n=1) and spondyloarthritis (n=1). MEFV gene sequencing had been performed in 2 patients showing no pathogenic variant, and one of them was heterozygous for the M680I mutation.
Prior to the diagnosis of AA amyloidosis, 19 patients (70%) were on colchicine, 15 patients were on immunosuppressants and 2 on corticosteroids only. At the time of amyloidosis diagnosis, 12 patients were off treatment, 8 were using an immunosuppressant (5 AZA, 2 CYC and 1 MTX), and 2 were using CS only.
Outcome:
Fourteen patients (52%) died after a median follow-up of 3 years (IQR: 7.75), 3 were lost to follow-up and 10 (37%) were still alive after a median follow-up of 11 years
(IQR: 16). The reasons for death were infections in 5 cases, complications related to end-stage renal failure in 5 cases, subarachnoid haemorrhage, gastric adenocarcinoma, cirrhosis associated with amyloidosis and iatrogenic intestinal perforation in one case each. Nine (64%) of the 14 patients who died had developed end-stage renal disease (ESRD).
Overall, 15/27 patients (55.5%) developed ESRD after a median follow-up of 3.5 years (IQR: 5.25) after diagnosis of AA amyloidosis. Five patients underwent renal transplantation.
A systematic review of the literature revealed 82 cases in 42 publications. The main characteristics of the patients were a predominance of males and a high frequency of vascular involvement. One third of patients died within 6 months of diagnosis of AA amyloidosis (table 1).
Discussion and conclusion:
According to the results of this study, the frequency of AA amyloidosis in patients with Behçet's disease appears to be decreasing. Male patients with major organ involvement, particularly vascular involvement, appear to be more likely to develop AA amyloidosis. Although AA amyloidosis rarely complicates Behçet's disease, its occurrence is observed in younger patients and it appears to worsen the overall prognosis of the disease.
