Our investigation has elucidated an elevated prevalence of IBD within the cohort of FMF patients, underscoring an augmented occurrence in comparison to the general population. While existing literature extensively explores the coexistence of FMF in individuals with IBD, limited attention has been directed towards scrutinizing the prevalence of IBD among FMF patients. In our study, unlike previous studies, the presence of IBD was investigated in a large FMF cohort and these patients were analyzed in detail.
In the study conducted by Yıldız et al., encompassing 686 FMF subjects, an IBD prevalence of 1.45% was established [18]. Similarly, another investigation involving 600 FMF patients revealed IBD in 1.16% of cases [19]. Within the scope of our own inquiry, this proportion was ascertained to be 0.76%. The prevalence of IBD in Turkey has been reported in the range of 6.6–44/100,000 in various studies [18]. Despite the potential onset of IBD at any age, the manifestation of symptoms typically occurs post-childhood, indicating a heightened rate compared to the general population [20]. Our study suggests a definitive association of this disease with FMF in the pediatric population.
In Turkish population, the prevalence of FMF carrier status is known to be 14.8% [21]. According to a study conducted by the FMF research group, which included 2838 patients, FMF disease is observed at a rate of 1 in 1000 individuals. The most common mutations in Turkish individuals diagnosed with FMF are M694V (51.4%), followed by M680I (14.4%) and V726A (8.6%). The M694V homozygous mutation was detected at a rate of 10.7% [22]. In contrast, M694V mutation is observed in healthy individuals at a rate of 3% [23]. In our investigation, the M694V mutation was identified in 5 patients (55%), M694V homozygous mutation in 4 patients (44%) and combined heterozygous mutation in 3 patients (33%) with FMF and IBD. These rates are notably higher compared to the FMF population [22]. It is also noteworthy that the prevalence of M694V homozygous mutation was 44% in the FMF and IBD group, compared to 19% in the entire FMF group in our study (p = 0.079). Due to the small sample size in the IBD and FMF group, we consider this difference to be statistically insignificant.
Pediatric IBD in our country is reported to have an association with FMF in 21.1% of cases. In a study of 597 IBD patients, MEFV mutation was detected in 41.8% of the patients and 21.4% of patients with mutation were reported to have M694V homozygous mutation [16]. According to Uslu et al.'s study, MEFV gene mutations were detected in 25.7% of 33 patients with IBD. While the most prevalent mutation in IBD patients is M694V (10.6%), M694V mutation was identified in 43.7% and M694V homozygous mutation in 18.1% of IBD and FMF patients [10]. In another study involving 53 IBD patients, associated 26.4% of cases with FMF. Among these patients, M694V homozygous mutation was detected in half, and 14.3% exhibited K695R and M694V heterozygous mutations [15]. According to our study, M694V mutation is the most common mutation in FMF and IBD patients and the prevalence of IBD is increased in FMF patients with M694V homozygous mutation.
In previous studies, diarrhea, abdominal pain, and rectal bleeding were reported as the most common symptoms in patients with coexisting FMF and IBD, in that order [15]. Similarly, our study also indicates that diarrhea is the most frequent complaint among patients with both FMF and IBD. Among the nine patients studied, four reported periodic diarrhea attacks, while five presented with chronic diarrhea. Rectal bleeding was observed in 77% of the patients. Those experiencing periodic diarrhea reported episodes with a frequency ranging from once a week to once every two months, with 4–6 attacks per day. These findings suggest that the presence of periodic or chronic diarrhea and rectal bleeding in FMF patients warrants careful evaluation for the potential coexistence of FMF and IBD.
When colonoscopic examinations of patients with FMF and IBD were analyzed, colon involvement was observed in all 11 FMF patients who underwent colonoscopy in a study conducted in our country (17). In the study by Beşer et al., colitis was found in 9 (75%) of 12 FMF and IBD patients, pancolitis in 2 (16.6%) and ileocolitis in 1(8.3%) [8]. In our study, colonoscopy was performed in all 9 patients. Colon involvement was observed in 6 patients (66%) and terminal ileum involvement was observed in 3 patients. This distribution of gastrointestinal involvement emphasizes the predominance of colonic symptoms in FMF and IBD patients and reflects the findings of previous studies.
All patients received colchicine treatment, with 8 colchicine-resistant cases additionally administered immunosuppressive therapies. Favorable outcomes were obtained in all patients except for the Patient 8, who exhibited ongoing minimal inflammatory changes in the colon mucosa during the follow-up colonoscopy. For IBD associated with FMF, it is recommended to administer treatments such as steroids, mesalamine, azathioprine, TNF inhibitors, in addition to colchicine, based on the type, involvement, and severity of IBD [8].
Our study has several limitations, notably its single-center and retrospective design. Despite these limitations, a significant strength of our research is the demonstration of the prevalence of IBD and the influence of the MEFV gene within a cohort of FMF patients. This comprehensive analysis will add valuable information to the understanding of the coexistence of FMF and IBD, potentially guiding future research and clinical management strategies.