Adverse drug reactions (ADRs) are a serious public health issue, being a major cause of morbidity and mortality. Clinical Decision Support Systems (CDSS) can reduce this phenomenon and the associated costs.
There are many studies measuring the incidence of ADR in inpatient ranging from 2.2 to 4.6 per 100 admissions. For example, in a study conducted in France, in Lille, over a period of 18 months, 371 ADRs were found in 336 patients out of a total of 16,916 inpatients, with an incidence of 2.2%. In a study carried out in Italy, Sicily, in 4,802 admissions a rate of 3.2% of ADR was found. Many other studies documented the same results, within the above mentioned range.
The incidence of ADR varies according to the patient age, the patient condition, the wards and the intensity of care. There are also studies on ADR in emergency rooms, in outpatient care and in primary care. ADRs, in addition to arising during hospitalisations, due to prescribed therapies, are also a source of hospitalisations and access to the emergency room.
In the study carried out in Lille the most common reactions were skin events (24%), cardiovascular events (21%), metabolic disorders (12%), coagulation disorders (10%) and disorders of the nervous system (10%). The classes of drugs most frequently involved were cardiovascular agents (36%), contrast agents (20%), blood coagulation drugs (13%) and anti-infectives (14%).
Adverse reactions result in a longer stay and higher costs for visits, examinations and medications. Many studies have focused on measuring the increase in hospitalization. Values that have been measured vary between 1.9 and 3 days. Some studies have then calculated the higher cost of hospitalisations because of ADR ranging between 2,500 and 5,000 US dollars that also includes and values the extension of the stay.
Not all adverse reactions can be avoided. According to the Schumock and Thornton algorithm (Schumock and Thornton, 1992), 69.4% of adverse reactions in hospital were related to ADRs that were probably preventable, 24.2% to inevitable and 6.4% to those that were certainly preventable. The most frequent types of drugs involved in probably preventable ADR belong to group “A” of the ATC classification (gastrointestinal tract and metabolism, 100.0%), specifically antidiabetics, followed by “B” (blood and hematopoietic organs, 88.9%), and “C” (cardiovascular system, 84.6%), mostly cardiac therapy (N = 13) and RAS inhibitors (N = 9). Other pharmacological groups were antimicrobials for systemic use (50.0%) and nervous system (50.0%).
Based on the incidence of ADR and the cost that each of these determines, it is possible to calculate, using the French study data, in 9,130 euros per 100 admissions the cost of ADR in hospitalised patients. The cost of avoidable ADRs is 6,336 euros for every 100 admissions. If we use the Italian study data, the cost is equal to 8,160 euros, estimating the total cost for each extra day of hospitalisation at 850 euros per day. The cost of avoidable ADRs is 5,553 euros for every 100 admissions.
Projected on an annual basis, we can say that the cost of avoidable ADR for a hospital of 700 beds is between 1.5 – 1.7 million euros every year!
But how can a CDSS help doctors prevent ADR? The following figure illustrates the dashboard of an advanced CDSS to assess the therapy and the risks involved.
The risk matrix shows the risks involved in the addition of amiodarone; in the example, an increased risk of drug interactions and torsades de pointes (QT prolongation). It is also not recommended for the elderly and for patients with liver failure.
On the top right are the alternatives for amiodarone, with the associated risk levels. Through the microscope icon it is possible to know which examinations should be prescribed in case of initiation of amiodarone therapy. The icon with the tablet symbol provides tips on additional drugs that should be considered according to the patient’s clinical picture.
A CDSS of this type shows drug interactions, contraindications for particular health conditions or ages, potential cross-sensitivities, as well as an evaluation for nine types of adverse effects. It provides physicians with a complete picture of the risks associated with the therapy and the possible therapeutic options.
Reducing 25% of avoidable ADRs with such a system would result in an annual saving of 375,000 – 425,000 euros for a 700-bed hospital. Savings of 750,000 to 850,000 euros would be made if the number of avoidable ADRs were to be reduced by 50%.
That’s why investing in CDSS is worthwhile!