Postoperative Prophylaxis of Cystic Echinococcosis with Albendazole and Praziquantel: A Retrospective Cohort Study

Background/Objectives: Cystic echinococcosis is primarily managed surgically, yet postoperative recurrence affects 2-22% of patients despite albendazole prophylaxis. This study describes the tolerability of adding praziquantel to postoperative albendazole and reports recurrence signals where efficacy cannot be inferred. Methods: In this single-centre, retrospective, two-arm cohort, 60 patients undergoing hydatid cyst surgery (2024-2026) received albendazole and 30 additionally received praziquantel. The follow-up was substantially shorter in the combination arm (median 10 versus 24 months), and recurrence was first ascertainable only from 12 months, the central limitation. Analyses used standardized mean differences, person time incidence, propensity score and inverse probability weighting, a DAG-based hepatotoxicity model, and a Bayesian Beta-Binomial re-analysis. Results: Baseline covariates were markedly imbalanced (14/15 with |SMD| > 0.10). Two recurrences occurred, both in the albendazole arm (3.73/100 person-years) and none in the combination arm's shorter window. Adverse events were similar (43.3% vs. 50.0%), with no added hepatotoxicity after adjustment (odds ratio 1.45, 95% CI 0.49-4.37). The Bayesian posterior probability of benefit (0.88-0.93) remained below 0.95, a descriptive signal only. Conclusions: Albendazole plus praziquantel was well tolerated, but severe baseline imbalance, differential follow-up, and only two events mean efficacy cannot be assessed. The results of our study are hypothesis-generating. Further confirmation requires a prospective, multicentre randomized trial with balanced long-term follow-up.