Agreement on the prescription of antimicrobial drugs

We found considerable differences between the specialists’ opinions about the prescribed
antimicrobial therapy, with less than half of the prescriptions being judged appropriate
by both (Table 2). In general it appears that specialist #1 has a more aggressive approach to the
use of antimicrobials, while specialist #2 was more conservative. We could not distinguish
a homogeneous pattern justifying such different approaches; however, when we analyzed
some diagnostic subsets within the sample with diverging opinions, we noticed that
specialist #1 was more aggressive with respect to those subgroups where the patients
had sepsis or where the antimicrobial therapy had been started empirically, and more
conservative when treating the subgroup in which the introduction or change in antimicrobial
therapy had been motivated by a positive culture, where he considered the regimen
to be broader than necessary or even unnecessary. It is difficult to understand the
reasons for this divergence. In the analysis of the data, we found no other characteristics
that might clarify this issue or reveal the nature of the differences in prescription
patterns between the two specialists. The act of prescribing depends on a series of
variables: medical knowledge, doctors’ and patients’ cultural beliefs, socio-economic
factors, a desire to make independent decisions, expectations about the outcome, ability
to break the inertia of routine practice and implement recommendations, medical hierarchy
and respect for peers 1], 15]. Factors like no familiarity with or no awareness of the guidelines as well as insufficient
knowledge about infectious diseases, potential causative agents and local susceptibility
may contribute negatively at the moment of prescribing these drugs 1], 13]. Furthermore, there is a prevailing feeling of safety and comfort with the use of
broad-spectrum empirical therapy, irrespective of the guidelines 13]; in addition, certain doctors overestimate their patients’ expectations about antimicrobials
and tend to prescribe these drugs as a means of strengthening a good doctor-patient
relationship 21], or to maintain collegial relationships between consultant physicians and the primary
service physicians.

In 29 % of the cases the specialists disagreed with each other, which may be explained
by individual professional characteristics 13], 22], differing choices of empirical therapy, experience and years of practice, and difficulties
of using more sensitive microbiological methods for diagnosis. The development of
techniques and resources that enable a faster and more accurate identification of
microorganisms and their susceptibility profile is warranted 14], 17]. The prior administration of an antimicrobial agent is the most important risk factor
for drug-resistant nosocomial infections since it predisposes the patient to colonization
by bacteria that are usually resistant to that agent 3], 9], 23]. In our study, 62.1 % of the patients had prior treatment with some form of antimicrobial
therapy: 20 % received carbapenems, 36 % glycopeptides and 64.5 % received combination
therapy (Table 7). Some studies indicate that over one-third of hospitalized patients receive at least
one antimicrobial during hospitalization 15], and among critically ill patients this rate exceeds 70 % 1], 2].

Some strategies seem to be effective in the fight against the increase of resistant
microorganisms and the indiscriminate use of antimicrobials. These include restriction
and pre-approval forms that limit the availability of antimicrobials 6], 12], 13], audits plus interventions 6], 16], an established prevention policy with more rational use of these agents, i.e., fewer
antimicrobials and shorter treatment duration 4], 6], 13], 16], microbiological surveillance 11], review of prescriptions and emphasis on appropriate use by the clinical pharmacist
13], 16], and implementation of an automated system for prescription of antimicrobials 4], 22], 23]. Behavioral approaches to optimize the prescription of antimicrobials do not seem
to have the expected result 15], 18], i.e. restrictive interventions are shown to be more effective than those based solely
on education and orientation 16], 17].

This study has some limitations, namely the fact that it was a single-center study
and data were randomly collected, i.e., not all patients who met the criteria were
included. Also, due to the method used for inclusion, some patients with an indication
for antimicrobial therapy and who remained untreated were not included in the sample
used to evaluate the agreement with the prescription. Furthermore, the study design
is not the best recommended for this type of assessment, since the specialists were
asked to judge the prescription as appropriate or inappropriate, and the specialist
may have been biased by the decision of the prescribing doctor. An alternative approach
would have been to ask the specialist to examine the patients’ records and prescribe
the antimicrobial regimen without reviewing the drugs that were actually prescribed.
Another difficulty with the study when comparing the assessment by the two specialists
is the lack of a gold standard. This would have been more easily accomplished should
100 % of our cultures yielded a microorganisms and an antibiogram on which to make
a decision (adequate or not adequate antimicrobial therapy). However, there is a low
rate of positivity of blood cultures in this population 24], which leads to diversity in antimicrobial practices.

While these data may not be entirely generalizable, they highlight the difficulties
in prescribing effective empirical antimicrobial therapy – they are of such magnitude
that even two specialists in infectious diseases, well acquainted with our hospital’s
resistance patterns and our patients’ profiles have considerable disagreement.

To minimize such differences we need faster and more accurate diagnostic tests as
well as a better understanding by frontline providers of clinical guidelines and local
susceptibility patterns. Only then can we reach a higher rate of agreement, and implement
rational and appropriate use of antimicrobials. Otherwise, in the future we may have
further selection of resistant microorganisms against which we scarcely have effective
therapeutic resources.