Fewer pills, better adherence? What the evidence on medication adherence says

A problem of global scale

The World Health Organization put a number on the issue as early as 2003 in its report “Adherence to long-term therapies: evidence for action”: in developed countries, adherence to long-term therapies averages only about 50 percent, and it is lower in developing countries. The WHO states: “Poor adherence is the primary reason for not achieving the full health benefits medicines can provide.”

The consequences range from complications and lower quality of life to resistance and avoidable costs for health systems. The WHO explicitly warns against blaming patients: health systems and care providers have a major influence on adherence.

What one tablet instead of many can do

A common obstacle is the complexity of therapy: several products, several times of day. How much simplification can achieve is shown by the UMPIRE trial, published in JAMA in 2013. 2,004 patients at high cardiovascular risk received either usual care with separate products or a so-called polypill that combines several active ingredients in one tablet.

At the end of the study, 86.3 percent of the polypill group were taking their medication, compared with 64.7 percent in the comparison group. Among those who were not taking all recommended medicines at the start, adherence rose from 23 to 77 percent with the polypill. Blood pressure and LDL cholesterol were slightly lower; the trial was not designed to show effects on cardiovascular events.

What the manufacturing process can contribute

This is where technologies come in that combine several active ingredients or release profiles in one dosage form. Evonik, which invested in Laxxon in 2022, expects printed tablets with targeted release to cause fewer side effects and require fewer tablets per day, which could reduce missed doses. According to the company, Laxxon only combines active ingredients in one tablet that are also usually given together in clinical practice, such as levodopa and carbidopa.

Whether results such as those from UMPIRE carry over to printed combination products will have to be shown by dedicated clinical studies. The direction, however, is clear: the simpler a therapy is in everyday life, the greater the chance that it is taken as intended.