The largest-ever assessment of high-deductible plans shows patients using these plans significantly cut back on preventive health care, even though they end up saving dramatically on costs.

"We discovered that costs go down dramatically during the first year people are enrolled in high-deductible health plans, as long as the deductible is at least $1,000 per person," says Amelia M. Haviland, a study co-author and a statistician at RAND, a nonprofit research organization. "But we also found concerning reductions in use of preventive care. This suggests people are cutting both necessary and unnecessary care."  

Studying more than 800,000 families from across the United States, researchers found that when people shifted into health insurance plans with high deductibles, their health spending dropped an average of 14 percent when compared to families in health plans with lower deductibles.