Gender and Ethnic Variations of Biliary Dilatation in Individuals on Methadone Maintenance Treatment: A Retrospective Observational Study in Inner City Population

Abstract

Introduction: Individuals with opioid dependency has been traditionally treated with Methadone in drug rehabilitation programs. Biliary dilatation can result from several pancreto-biliary diseases including choledoholithiasis and malignancies. However, non-pathological dilatation of biliary duct can result from chronic methadone use. We designed our study to evaluate gender and ethnic variations of biliary dilatation in individuals on Methadone Maintenance Treatment (MMT). Methods: We conducted cross sectional observational study of all patients admitted to out hospital who are currently enrolled in MMT program and receiving methadone. We excluded patients taking methadone for pain management and palliative purposes. We also excluded patients with choledocholithiasis, pancreato-biliary malignancies and had cholecystectomy in the past. We collected demographic, laboratory and ultrasound imaging details by accessing our electronic medical records. We divided the patients into two groups based on common bile duct dilatation of more than 6 mm. Data was analyzed using standard statistical methods and JMP 12 software. Results: There were a total of 176 patients who met inclusion criteria. There was no difference in ethnicity and age between the two groups (Table 1). We also did not notice any difference in mean methadone dosage between the two groups. However, we observed more females (50 % vs 36% p 0.04) in the group with biliary dilatation compared to group without biliary dilatation. We also observed that mean CBD diameter in females is more than their male counter parts (6.8 mm vs. 5.8 mm, p 0.03)Table 1Conclusion: Methadone has been known to be associated with non-pathological biliary dilatation. Our study concluded that female gender is more commonly associated with biliary dilatation in individuals on MMT. We also conclude that mean biliary diameter is higher in females compared to males. Even though common physiological pathway can lead to non-pathological dilatation of biliary tract in patients on MMT, females are more likely to have biliary dilatation. Further research at molecular level can track the physiological phenomenon leading to these changes.