Background: Familial Mediterranean fever (FMF) is an autoinflammatory disease with
potentially devastating effects on the kidney, and the chronic subclinical inflammation may also be
deleterious. Further, proteinuria has been associated with chronic inflammatory states.
Objective: We aimed to probe whether red cell distribution width (RDW) can be used as a reliable
indicator of subclinical disease in FMF patients.
Methods: Ninety-nine children with FMF, according to the new pediatric FMF criteria, were included
in the present study. All were attack-free at the time of the study. They were compared with
44 healthy age-matched controls. For all patients and controls, the following tests were done: Complete
blood count (in the form of red cell count, leukocyte count, platelet count, hemoglobin, RDW
and MCV), CRP, ESR, creatinine and an estimated glomerular filtration rate (e-GFR). For patients,
serum and urine albumin and albumin/creatinine ratio were also determined. Group 1 consisted of
61 patients, who were not suffering from microalbuminuria, and Group 2 consisted of 38 patients
who had confirmed albuminuria.
Results: RDW and ESR were significantly higher in patients with FMF without microalbuminuria
than in controls, while MCV was smaller in controls (p<0.05).
Conclusion: RDW can be used as an indicator of subclinical inflammation in children with FMF.
The tests are easy to perform and cheaper than more sophisticated tests. Microalbuminuria may be
silent and occur on the background of normal levels of acute-phase reactants. All cases must be
routinely checked for microalbuminuria.