The Pharmaceutical Care Management Association conducted a study of three-tier co-payment systems in conjunction with Express Scripts, and found that the programs yield about 17.1 percent in savings. In 1998, only 38 percent of health plans offered three-tier with an average of 9 percent enrollment, but in 2000, about 80 percent of health plans offered the option and garnered 40 percent enrollment. Three-tier programs are expected to grow in popularity as small and mid-sized employers attempt to reduce their health care expenses. The study also indicated that chronic therapeutic drug sales--estrogen, oral contraceptives, antihypertensives, and lipids--remained unaffected under the new program. Emergency room visits and hospitalizations also remained unaffected by the new system, which indicated that patient care would not suffer under a new cost distribution system. Express Scripts also studied the effects of aggressive three-tier prescription drug programs on savings. Those plans that are more aggressive--which increase copays at the tier-one and tier-two levels as well as the tier-three level--resulted in a negative trend and improved savings. However, Brenda Motheral--co-author of the study and senior director of outcomes research for Express Scripts--suggested that employers with lower-income workers take a less aggressive approach to their prescription drug program to ensure employee health.