Medication Use Studies

Medication use studies

Decision making to achieve efficient use of therapeutic resources requires having information and applying technical knowledge. The concepts and methodological tools from the field of epidemiology have shown their great utility, so that in recent years disciplines such as pharmacoeconomics, medical technologies or evidence -based medicine evaluation have been incorporated in a massive way. In the drug field, the application of epidemiological/population methods offers an alternative to increase the degree of information available. On the one hand, it is about integrating the information from the experience of use when drugs are used in usual conditions of clinical practice, and on the other hand know the determinants of their use. Clinical epidemiology, which Spitzer defines as "the study of determinants and the effects of clinical decisions" consists of a way of applying the epidemiological method to the population "patients" and focusing the point of observation on clinical care.

Also to respond to very similar issues, pharmacoepidemiology focuses observation in drugs, applying the epidemiological method to the general population or the population "patients". Porta and Hartzema have defined this discipline as "the application of the knowledge, methods and reasoning of epidemiology to the study of the effects – positive and negative – and uses of drugs in groups of populations".

For the hospital pharmacist, the knowledge of pharmacoepidemiology is necessary to help in the critical interpretation of scientific literature on drugs and its conversion into parameters applicable to decision making.

The criteria and methods of pharmacoepidemiology are useful for developing their activities in areas such as medication evaluation, pharmacovigilance and in the design of studies and programs. 

WHO defines drug use studies (EUM) as "studies on marketing, distribution, prescription and use of medicines in society, with a special accent on medical, social and economic consequences" 

EUM can be classified in various ways depending on whether their objective is to obtain quantitative information (amount of medication sold, prescribed, dispensed or consumed) or qualitative (therapeutic quality of the medication sold, prescribed, dispensed or consumed). Medication use studies can also be classified according to the main element they intend to describe:

•  Consumer studies: describe what medications are used and in which amounts.
•  Prescription-Indication Studies: Describe the indications in which a certain drug or group of drugs is used.
•  Studies Indication-Prescription: Describe the drugs used in a certain indication or indications group.
•  Studies on therapeutic pattern (or therapeutic scheme): describe the characteristics of the practical use of medicines (dose, monitoring of plasma levels, duration of treatment, compliance, etc.).

The prescription and indication-prescription studies are studies that allow deepening a potential problem detected and knowing some of the reasons for the prescription of drugs. They are based on a pathology or indication (indication-prescription) and the prescriptions associated with it are identified, or it is based on a drug or group of drugs (prescription-indication) and the indications for which they are used are analyzed.

The designs can be:

• Retrospective, by reviewing medical records or pharmacotherapeutic stories obtained from computerized records in a unit dose system.
• Transversal or prevalence, in samples of patients who, at a given time, receive a drug or present a pathology.
•  Prospective, by monitoring a cohort of patients with a certain pathology or real -time detection of all prescriptions of a certain medication.

This design allows, at the same time, the analysis of other factors related to the use of medicines (for example, the evaluation of compliance by patients), but also allows, above all, the realization of interventions that increase the qualityof the use of medicines before it occurs (for example, suggestions on the selection or the positive of the drug, and evaluation of the impact of these). The objectives of these studies may be aimed at specific aspects, such as the evaluation of compliance with prescription by patients, the detection of medication errors, in all their aspects, or to the detection of problems related to medication in aPharmaceutical Care Context.

Perspective of drug use studies

The resources that a society can allocate to health in general, or to medications in particular, are not unlimited. This fact forces to assess the expense generated by the different health strategies, including medicines, as an important variable.

In our environment, during the last years the increase in medication spending has been a reason for concern. However, to assess this data we must place it in the most global context of health spending and have detailed information on the characteristics of the use of medicines that generate said expense. 

For a few years there is a great concern for increasing antimicrobial resistance. From various institutions and organizations different strategies have been proposed to try to control and reduce this increase. Within the hospital scope they have been suggested: the monitoring of antimicrobial consumption, the study of prescription habits and the analysis of the resistance trends of different microorganisms, as effective strategies to prevent this problem.

It is assumed that hospital antibiotic policy has a very significant impact on the selection of resistant bacterial strains, although there are few studies that support this idea in a conclusive way from the statistical point of view. Although the economic concern is logical, the need for the EUM does not depend on the expense generated by the use of medicines (UM) but rather on the approach to what health needs the population has and that pharmacological strategies we have to give them aresponse.

The appropriate question is whether pharmacological therapy (which generates an expense) is optimal and valu. For this, it is necessary to have sufficient descriptive information of reality and it is essential.  Hospitable pharmacy services (SF) are strategic places from which to propose EUM and thus deepen the use of therapeutic groups considered of interest or relevance for their clinical consequences (efficacy and safety) or economic in patients in patients in patients. In addition, it is important to carry out local studies to define a problem, in order to make decisions in public health according to the reality of a certain place. 12

Finally, other very important factors that make the development of activities in the field of the EUM should be taken into account: the constant marketing of new drugs, also the constant contribution of new therapeutic knowledge from clinical trials and the growing demand forquality assistance (which includes pharmacological treatment) from multiple areas.

In summary, the EUM allow us to know the use of medicines in clinical practice and identify problems related to their use, and subsequently design intervention strategies in order to achieve the most suitable, effective, safe and efficient use of medicines.