The researchers compared the following 5 strategies: no treatment, interferon, lamivudine, adefovir, and lamivudine followed by adefovir if drug resistance developed (adefovir salvage). They reviewed medical literature to find information about the benefits and adverse effects of each approach. They also calculated the costs of each regimen, including its potential complications, and the health care costs of caring for patients with chronic liver disease. They then used a computer model to combine these data and estimate the cost-effectiveness of different treatment approaches over a patient's expected lifetime.