Interventions designed to narrow the gap between research findings and clinical practice may be effective, but also costly. Economic evaluations are necessary to judge whether such interventions are worth the effort. We have evaluated the economic effects of a tailored intervention to support the implementation of guidelines for the use of antihypertensive and cholesterol-lowering drugs. The tailored intervention was evaluated in a randomized trial, and was shown to significantly increase the use of thiazides for patients started on antihypertensive medication, but had little or no impact on other outcomes. The increased use of thiazides was not expected to have an impact on health outcomes.
Methods and Findings
We performed cost-minimization and cost-effectiveness analyses on data from a randomized trial involving 146 general practices from two geographical areas in Norway. Each practice was randomized to either the tailored intervention (70 practices; 257 physicians) or control group (69 practices; 244 physicians). Only patients that were being started on antihypertensive medication were included in the analyses. A multifaceted intervention was tailored to address identified barriers to change. Key components were an educational outreach visit with audit and feedback, and computerized reminders. Pharmacists conducted the visits. A cost-minimization framework was adopted, where the costs of intervention were set against the reduced treatment costs (principally due to increased use of thiazides rather than more expensive medication). The cost-effectiveness of the intervention was estimated as the cost per additional patient being started on thiazides. The net annual cost (cost minimization) in our study population was US$53,395, corresponding to US$763 per practice. The cost per additional patient started on thiazides (cost-effectiveness) was US$454. The net annual savings in a national program was modeled to be US$761,998, or US$540 per practice after 2 y. In this scenario the savings exceeded the costs in all but two of the sensitivity analyses we conducted, and the cost-effectiveness was estimated to be US$183.
We found a significant shift in prescribing of antihypertensive drugs towards the use of thiazides in our trial. A major reason to promote the use of thiazides is their lower price compared to other drugs. The cost of the intervention was more than twice the savings within the time frame of our study. However, we predict modest savings over a 2-y period.
The importance of bridging the gap between research and practice, and the need to improve the prescribing practices of family doctors (general practitioners), is discussed in the Editors' Summary for an article related to this one (DOI:
10.1371/journal.pmed.0030134). However, measures to improve prescribing practice can be expensive. Economic evaluations are necessary to judge whether such measures are worth the effort.
Doctors in a Norwegian study, described in the related article, were encouraged to make more use of drugs belonging to the thiazide “family” to treat high blood pressure (hypertension). Thiazides are cheaper than other antihypertensive drugs and in the average patient at least as effective. Increasing their use should therefore save health services money, but not reduce the effectiveness of the treatment of hypertension. The study found that measures to actively encourage doctors to follow prescribing guidelines did increase the use of thiazides, but only by a small amount.
Why Was This Study Done?
After having found that active promotion of guidelines can make a difference, the researchers wanted to know whether the cost of the efforts they made to encourage doctors to follow the guidelines were justified by the savings made by increased use of the cheaper drugs.
What Did the Researchers Do and Find?
They calculated the money saved where the prescribing guidelines were actively promoted, and then worked out what this would amount to if the same were done in all the family practices in Norway. They found that the cost of promoting the guidelines was greater than the savings achieved during the course of their study, which lasted one year. However, their calculations show that after two years the money saved would have exceeded the costs. After that, the savings would increase every year.
What Do These Findings Mean?
As far as this particular example of prescribing practice is concerned, although active promotion of guidelines increased costs in the short term, it will soon produce savings. This will not always be the case; efforts to change prescribing practice may sometimes involve the use of more effective but costlier drugs. Improving the care of patients must always be the main aim, but encouraging doctors to follow recommended guidelines on the prescribing of drugs can sometimes reduce costs, too. These issues are discussed further in a Perspective about this study (DOI:
A significant increase in prescribing of thiazides, in preference to more expensive antihypertensives, resulted from active promotion of guidelines. The cost of the intervention was greater than the saving during the study period. Modest savings are predicted after two years.