In a new study, researchers found important drugs for the treatment of heart failure are often prescribed in lower dosages than recommended by international guidelines.
The finding shows overly cautious prescription of the most common drugs by physicians due to bias.
The research was conducted by a team from the Medical University of Vienna.
Heart failure is one of the most frequent diseases in western countries.
Angiotensin converting enzyme (ACE)-inhibitors, betablockers and angiotensin receptor blockers (ARB), which have clear guidelines on prescription practice, are used for treatment.
In the study, the team examined the dosages prescribed to outpatients based on the national Austrian Heart Failure Registry comprising 3,737 patients.
During an observation period of 12 months, only a limited number of the patients with chronic systolic heart failure received the recommended maximal dosages.
Most patients were below the recommended optimal therapeutic dosage.
This became particularly clear within a substance class with different numerical maximum dosages to achieve the same therapeutic effect.
Thus, medication with a higher target dosage in absolute numbers (e.g. betablocker 10mg vs 200mg) were prescribed at a significantly lower dosage than recommended, while the probability that the maximum target dosage was prescribed was considerably greater in medication with a lower numerical target dosage.
The team says unconscious cognitive bias is responsible.
There is an unconscious fear of overdosing and a fear of side effects of medication among doctors, which continues to exists also in evidence-based medicine.
This is particularly relevant the greater the target dosage of a pharmaceutical product, and prevents the administration of the dosage tested as optimal in pivotal studies.
The team assumes that this overly cautious behavior is not a particular problem of cardiological treatments, but that this overcautiousness in the dosage of prescription also exists in other medical sectors.
Further studies will trace this bias in other medical specialties and diseases.
If the results are confirmed, the authors recommend supplementing the guideline recommendations based on milligram dosages with guidelines based on equivalence dosages.
Prescription of the correct and tested medication dosage is important to achieve the intended therapeutic effect and to provide patients with the best possible quality of life, in this case relating to heart failure.
The study is published in the journal Annals of Internal Medicine.
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