Objectives: The Weight Loss Maintenance Trial (WLM) was a multicenter, randomized trial comparing two weight loss maintenance interventions, a personal contact (PC) program with primarily telephone-based monthly contacts, and an Internet-based program (interactive technology, IT), to a self-directed control group, among overweight or obese individuals at high cardiovascular risk. This study describes implementation costs of both interventions as well as IT development costs.

Methods: Resources were micro-costed in 2006 dollars from the primary perspective of a sponsoring healthcare system considering adopting an extant intervention, rather than developing its own. Costs were discounted at 3 percent annually. Length of trial participation was 30 months (randomization during February–November 2004). IT development costs were assessed over 36 months. Univariate and multivariate, including probabilistic, sensitivity analyses were performed.

Results: Total discounted IT development costs over 36 months were $839,949 ($2,414 per IT participant). Discounted 30-month implementation costs for 342 PC participants were $537,242 ($1,571 per participant), and for 348 IT participants, were $214,879 ($617 per participant). Under all plausible scenarios, PC implementation costs exceeded IT implementation costs.

Conclusions: Costs of implementing and operating an Internet-based intervention for weight loss maintenance were substantially less than analogous costs of an intervention using standard phone and in-person contacts and are of a magnitude that would be attractive to many health systems, subject to demonstration of cost-effectiveness.