Increased Insulin Resistance after Praziquantel Treatment in Human Opisthorchiasis

Opisthorchiasis caused by Opisthorchis viverrini is a significant public health problem in northeast Thailand, a region where the prevalence of type 2 diabetes mellitus (T2DM) substantially exceeds the national average. Although recent evidence suggests that hyperglycemia may occur after praziquantel (PZQ) treatment, the underlying mechanisms remain poorly understood. We conducted a prospective 12-month follow-up study of 110 O. viverrini-infected patients receiving PZQ treatment, assessing fasting plasma glucose (FPG), oral glucose tolerance test (OGTT), and fasting serum insulin (FSI) at baseline and 12 months posttreatment. Praziquantel treatment was associated with significant increases in FPG (87.4 ± 1.0 versus 92.4 ± 1.7 mg/dL; P = 0.010), FSI (9.6 ± 0.7 versus 13.4 ± 1.1 µU/mL; P = 0.003), and homeostatic model assessment of insulin resistance (HOMA-IR; 2.2 ± 0.2 versus 3.0 ± 0.3; P = 0.001) at 12 months, whereas OGTT values did not differ significantly (P = 0.790). General linear model analysis identified age 50 years old and older and baseline obesity as significant factors associated with elevated FPG, whereas female sex, alcohol consumption, and baseline obesity correlated with higher OGTT values. Interestingly, HOMA-IR was significantly associated with underweight status at both baseline and follow-up. These findings suggest that O. viverrini eradication by PZQ increases insulin resistance in opisthorchiasis patients, potentially elevating T2DM risk. This effect likely reflects the loss of helminth-induced immunomodulation after parasite clearance, which is potentially compounded by improved appetite and increased food consumption after treatment, suggesting that metabolic surveillance should be integrated into liver fluke control programs.