Investigation of joint hypermobility in individuals with hyperbilirubinemia

Benign joint hypermobility syndrome refers to hypermobile individuals with musculoskeletal symptoms in the absence of any systemic rheumatic disease; its prevalence is approximately 0.5%. In animal studies, bilirubin has been shown to reduce fibrosis induced by bleomycin. It has been suggested that bilirubin leads to hypermobility that affects the structure or function of collagen. In addition, our observation is that hypermobility occurs more often in patients with indirect hyperbilirubinemia. In this study, we aimed to evaluate hypermobility in patients with indirect hyperbilirubinemia.

We recruited 120 consecutive patients with indirect hyperbilirubinemia from a tertiary gastroenterology outpatient clinic and examined them for hypermobility. Hypermobility was evaluated using the Beighton criteria, and other relevant clinical findings were recorded. In addition, a group of healthy individuals (n=107) without hyperbilirubinemia were included as controls.

The mean ages of the patients and controls were 33.4±12.9 and 36.2±11.2 years, respectively (p=0.09). In total, 100 (83%) patients and 78 (73%) controls were male (p=0.075). The mean indirect bilirubin levels were 1.44±0.66 mg/dL in the patient group and 0.37±0.18 mg/dL in the control group. Based on the Beighton score, 23 patients (19.2%) in the patient group and 3 (2.8%) individuals in the control group had joint hypermobility. The difference between the groups was statistically significant (p<0.001).

According to the results of our study, findings of joint hypermobility are more frequent in patients with indirect hyperbilirubinemia than in controls.