Clinical features, functional status, and quality of life in patients with late-onset familial Mediterranean fever.

Objective: This study aimed to determine the frequency of late-onset familial Mediterranean fever (FMF) and compare the clinical and genetic features, functional status, and health-related quality of life (QoL) of patients with early-onset and late-onset disease.

Methods: Patients with onset of symptoms ≤20 and >20 years of age were classified as early-onset and late-onset FMF, respectively. The clinical characteristics, MEFV gene mutations, and Pras disease severity scores were recorded. Physical disability and QoL were assessed with the health assessment questionnaire (HAQ) and short form 36 (SF-36), respectively.

Results: The mean age of 138 patients (104 women and 34 men) was 37.7±12.69 years. The percentages of patients with early- and late-onset FMF were 68.1% and 31.9%, respectively. Female sex, mild disease, arthritis, and sacroiliitis were more common in the late-onset group (p<0.05). The delay in diagnosis was shorter in the late-onset disease group (p<0.001). The percentage of homozygous M694V mutations was lower in late-onset disease (p=0.015). There were no differences in HAQ and SF-36 scores between early- and late-onset diseases (p>0.05).

Conclusion: The patients with late-onset FMF had a female predominance, a shorter delay of diagnosis, more frequent arthritis and sacroiliitis, a less frequent homozygous M694V mutation, and a milder disease severity than those with early-onset disease. Physical function and health-related QoL were similar in early- and late-onset FMF groups.