The study revealed where enrollment has declined most and where it has held steady:

• South Dakota has the highest rate of private-sector employees enrolled in HDHPs for the second year in a row. Three-fourths of employees were enrolled in HDHPs. South Carolina (70.2%) and Utah (70.1%) follow, up significantly from the previous year.
• Hawaii ranks last for the second year in a row, with just 12.7% of private-sector employees enrolled in HDHPs. It’s the only state with a rate below 30%. The District of Columbia (32.6%) and California (34%) round out the bottom three.
• South Carolina saw the largest percentage point increase in private-sector employees enrolled in HDHPs over the previous year. It had a 12 percentage point increase in the rate of these employees enrolled in HDHPs, which was the only double-digit jump. Utah (9.5%) and Vermont (9.4%) follow.
• The rate of private-sector employees enrolled in HDHPs in Montana fell by 20.9 percentage points, the biggest drop of any state. In a distant second, this rate fell 14.3 percentage points in Massachusetts, followed by Wisconsin (13.3%).

HDHPs can be a good option in some situations but not in others, Sangameshwar
said. She shared her insights into who may benefit.

"If you’re in good health, have extra money to set aside in a health savings account and plan to use your insurance mainly for routine preventive screenings, an HDHP can help maximize your health care dollars," she said. "If you pay up front for covered medical expenses, you may be charged a lower, negotiated rate between the health care provider and the insurance company. Preventive services like vaccinations, colonoscopies, mammograms and flu shots are also fully covered, so there’s no need to budget for these services."