Predictors of proteinuria, amyloidosis and kidney failure in familial Mediterranean fever: data from the International AIDA Network Registry

Objectives Proteinuria, amyloidosis and kidney failure are the main long-term renal complications of FMF. This study assesses their risk factors, independent of ethnicity or residence. Methods Patients' data were drawn from the International AIDA Network registry for monogenic autoinflammatory diseases. Results A total of 598 FMF patients were enrolled, with 80 having proteinuria, 61 amyloidosis and 25 kidney failure. At multivariate regression analysis, proteinuria was associated with out-of-flares thrombocytosis (odds ratio [OR]: 4.78, 95% CI: 1.54-14.8, P = 0.007), increased out-of-flares ESR (OR: 2.7, 95% CI: 1.3-5.6, P = 0.008), homozygous M694V mutation (OR: 2.27, 95% CI: 1.1-4.66, P = 0.025) and heterozygous M694V mutation (OR: 0.29, 95% CI: 0.09-0.86, P = 0.026); amyloidosis was associated with the disease duration (OR: 1.034, 95% CI: 1.004-1.065, P = 0.027), during-flares anaemia (OR: 2.9, 95% CI: 1.18-7.19, P = 0.021), out-of-flares leucocytosis (OR: 7.47, 95% CI: 1.6-34.7, P = 0.01), increased out-of-flares ESR (OR: 3.6, 95% CI: 1.48-8.81, P = 0.005) and heterozygous M694V mutation (OR: 0.18, 95% CI: 0.035-0.9, P = 0.04); kidney failure was associated with the age at diagnosis (OR: 1.04, 95% CI: 1.0003-1.19, P = 0.048), the disease duration in years (OR: 1.07, 95% CI: 1.02-1.12, P = 0.005), attack frequency per year (OR: 1.04, 95% CI: 1.007-1.076, P = 0.019), anaemia out-of-flares (OR: 4.7, 95% CI: 1.004-22.1, P = 0.049) and out-of-flares leucocytosis (OR: 25.8, 95% CI: 2.75-242, P = 0.004). The intraclass correlation coefficient related to ethnicity and country of residence was 6.7% and 6.8% for amyloidosis, respectively, and 0% for proteinuria and kidney failure. Conclusion FMF patients with older age at diagnosis, longer disease duration, anaemia, leucocytosis, thrombocytosis, elevated ESR and homozygous M694V mutation are at higher risk of kidney complications.