About 40 percent of those surveyed said their plans today would trigger the so-called Cadillac tax imposed on "rich" company plans by the Patient Protection and Affordable Care Act. With an eye on that added burden, due to take effect in 2018, large employers in particular are scouring their plans for ways to reduce cost.

Among the general plan designs contemplated by those who participated in the survey: "embracing new ways to deliver care through innovative network arrangements, focusing on increasing employee engagement and exploring new options for delivering benefits. This includes assessment of active employee private exchanges and a rapid migration of Medicare retirees to private exchanges," the survey said. (Towers Watson offers a private exchange service.)

Among specific actions that employers plan to take:

• An increase in the number of plans that include spousal surcharges, to 61 percent within three years, compared to 32 percent today;

• A significant reduction in coverage for spouses and dependents by 2018 is contemplated by 53 percent of those responding to the survey;

• 41 percent say they are examining the adoption of a defined contribution plan arrangement by 2018.

The study indicated that a growing number of employers are using metrics and measures to evaluate their health care spending per employee, and the "centers of excellence" concept is also taking hold. Plan inclusion of telemedicine as a substitute for in-person medical consultations was up 35 percent over last year; 80 percent said they'd be offering telemedicine services by 2018.

Towers Watson cited the following as "the most popular tactics for boosting employee engagement in health care:"

• Education and tools for better decision making. Nearly half of employers (48 percent) will place more emphasis on educating employees about how to select providers based on quality and cost information over the next two years. In 2016, 43 percent of employers will provide price and quality transparency tools to help employees make better consumer choices.
• Mobile apps to deliver health messages. Today, 60 percent of employers deliver health and wellness messages through mobile apps and portals. That percentage will increase to 95 percent by 2018.
• Account-based health plans as the only plan option. While 17 percent of employers offer full-replacement ABHPs (high-deductible plans tied to tax-advantaged health savings accounts), the percentage may increase to nearly 50 percent by 2018.

The survey found that 26 percent of respondents had "extensively analyzed" private exchanges, and 20 percent said their interest in shifting employees to a private exchange for coverage had increased compared to a year ago.