APPRAISAL OF THE VARIABILITY AND SUITABILITY OF PRESCRIBING ANTIMICROBIALS IN PRIMARY HEALTH CARE IN THE BASQUE COUNTRY

INTRODUCTION

Infectious diseases represent one of the main causes of mortality in our environment and are one of the main reasons for going to a doctor, both in general medicine (more than 20 %) and in paediatrics (40%).

Antibiotics (ATBs) are one of the most highly prescribed pharmacological groups in Primary Health Care (PHC): they represent between 10% and 15.2 % of the total number of drugs prescribed. It is estimated that in PC they constitute 90% of the total ATBs consumed.

The excessive consumption and inadequate prescription of ATBs have serious consequences for public health, such as: the appearance of bacterial resistances, the exposure to toxic and secondary effects, the increase in morbility, etc. It also represents an unnecessary increase in cost.

Bacterial resistances in Spain may be considered to be high and the resistance patterns vary according to different geographical areas, even within the Basque Country.

The correct prescription of antimicrobials is a priority of both national (Health Ministry) and international bodies (WHO). Within the recommendations proposed for their improvement, emphasis is laid on the prescription profiles of professionals as well as their adaptation to different processes.

Several surveys have shown that continuous medical training initiatives based on the local problems of antimicrobial therapy lead to a more rational prescription of these drugs and a more efficient treatment. For these programmes to be effective they must be integrated into the habitual activities of each centre and must be revised and discussed in accordance with the development of resistances and tendencies in the consumption of antibiotics.

These strategies require constant and efficient co-ordination between those who issue prescriptions (family physicians and paediatricians) and professionals involved in the antibiotics policy of their area: microbiologists, PHC pharmacists and epidemiologists.

Recent assessments of the main issues patterns involved in the use of antibiotics in our Community show a great deal of variability between different regions and even between different health centres located in the same region.

The aim of this survey was to study the variability and suitability of the prescription of ATBs in our Autonomous Community, together with an appraisal of bacterial resistances and an economic assessment of the cost of the treatment with antibiotics prescribed unnecessarily. In order to put this survey into perspective, a study has also been made of the development of infectious diseases and of the prescription of antibiotics over the last 10 years in the Basque Country.

MATERIAL AND METHODS

In order to achieve our aims, 6 different surveys were carried out during 1998.

1. Survey of the development of infectious diseases in the Basque Country over the period 1986-1996
   The annual incidence rates were calculated in accordance with the Notifiable Diseases (ND) rates weekly, grouping infectious processes in two categories (digestive transmission pathology and air transmission pathology).
   The population data correspond to those published by EUSTAT-Basque Statistics Institute for the 1986 register and 1991 census. The population figures for the periods between these censuses were estimated by interpolation and extrapolation.
2. Appraisal of bacterial resistance
   In January 1998, data began to be gathered on the resistance of the micro-organisms most frequently implicated in high respiratory tract pathology to antimicrobials (S. pneumoniae, S. pyogenes, H. influenzae), non complicated urinary infection (E. coli) and C.jejuni as the cause of infectious diarrhoea susceptible to antibiotic treatment.
   The archives of the Microbiology Service of the Aranzazu Hospital was used as a source for this data. The results obtained correspond to Gipuzkoa, which are expressed in percentages of resistant strains.
   For E. coli, urine infections outside hospitals in the San Sebastián area were selected, the susceptibility study being carried out by means of micro-dilution in culture medium.
   Both for Streptococcus pneumoniae and for Streptococcus pyogenes, a micro-dilution in culture medium system was also used, while for H. influenzae and Campylobacter jejuni the technique used was disk-diffusion.
   In all cases, the susceptibility criteria followed were described by NCCLS (National Committee for Clinical Laboratory Standards) in 1997.
3. Assessment of the consumption of antibiotics in the Basque Country during the period 1988-97 and its bearing on infectious diseases and bacterial resistances.
   Descriptive survey on the consumption of ATBs between 1988 and 1997. The ECOM database of the Ministry and Health and Cosumer Affairs was used.
   Consumption data was expressed in defined daily doses (DDD) per 1000 inhabitants and day (DID), in line with the recommendations of the OMS. The reference values used are those published by the WHO Collaborating Centre for Drug Statistics (Anatomical Therapeutic Chemical Classification Index, 1988). For the main actives not included in this list, the daily doses recommended by the Andalusian Health Service Working Group have been used in order to determine DDDs. When not found in this list, those recommended by the manufacturing laboratory were used.
   An analysis was made of the consumption in DID of the following sections: overall consumption of ATBs, consumption per therapeutic groups of ATBs, consumption of cephalosporins per generation and per administering method and consumption of macrolides.
4. Descriptive survey on antibiotic indication-prescription
   A survey was made in order to determine the prescriptions made, at a given moment in time, to treat infectious diseases, requested by doctors (family and paediatricians) belonging to the primary care health service.
5. Drawing up of recommendations on the appropriate use of ATB in Primary Health care
   Bibliographical review of the scientific literature in bibliographical databases: Medline, Embase, Cochrane Library, Best Evidence and INAHTA.
   Identification and selection of quality surveys that comply with the inclusion criteria previously established in the survey, making a synthesis and presentation in the form of tables of the evidence offered by the relevant surveys.
6. Economic assessment of the consumption of antibiotics
   The total amount consumed in antibiotics during the period studied was calculated. To make a real estimation of the increase in expenditure, current pesetas were adjusted to constant pesetas, using the annual CPIs and taking 1997 as the base year.
   Once the indication-prescription survey had been made, it was decided to estimate what could have been saved, should antibiotics not have been prescribed for viral infections for which there were no instructions to use these.

RESULTS

In order to achieve our aims, 6 different surveys were carried out during 1998.

1. Survey of the development of infectious diseases in the Basque Country over the period 1986-1996
   The annual incidence rates were calculated in accordance with the Notifiable Diseases (ND) rates weekly, grouping infectious processes in two categories (digestive transmission pathology and air transmission pathology).
   The population data correspond to those published by EUSTAT-Basque Statistics Institute for the 1986 register and 1991 census. The population figures for the periods between these censuses were estimated by interpolation and extrapolation.
2. Appraisal of bacterial resistance
   In January 1998, data began to be gathered on the resistance of the micro-organisms most frequently implicated in high respiratory tract pathology to antimicrobials (S. pneumoniae, S. pyogenes, H. influenzae), non complicated urinary infection (E. coli) and C.jejuni as the cause of infectious diarrhoea susceptible to antibiotic treatment.
   The archives of the Microbiology Service of the Aranzazu Hospital was used as a source for this data. The results obtained correspond to Gipuzkoa, which are expressed in percentages of resistant strains.
   For E. coli, urine infections outside hospitals in the San Sebastián area were selected, the susceptibility study being carried out by means of micro-dilution in culture medium.
   Both for Streptococcus pneumoniae and for Streptococcus pyogenes, a micro-dilution in culture medium system was also used, while for H. influenzae and Campylobacter jejuni the technique used was disk-diffusion.
   In all cases, the susceptibility criteria followed were described by NCCLS (National Committee for Clinical Laboratory Standards) in 1997.
3. Assessment of the consumption of antibiotics in the Basque Country during the period 1988-97 and its bearing on infectious diseases and bacterial resistances.
   Descriptive survey on the consumption of ATBs between 1988 and 1997. The ECOM database of the Ministry and Health and Cosumer Affairs was used.
   Consumption data was expressed in defined daily doses (DDD) per 1000 inhabitants and day (DID), in line with the recommendations of the OMS. The reference values used are those published by the WHO Collaborating Centre for Drug Statistics (Anatomical Therapeutic Chemical Classification Index, 1988). For the main actives not included in this list, the daily doses recommended by the Andalusian Health Service Working Group have been used in order to determine DDDs. When not found in this list, those recommended by the manufacturing laboratory were used.
   An analysis was made of the consumption in DID of the following sections: overall consumption of ATBs, consumption per therapeutic groups of ATBs, consumption of cephalosporins per generation and per administering method and consumption of macrolides.
4. Descriptive survey on antibiotic indication-prescription
   A survey was made in order to determine the prescriptions made, at a given moment in time, to treat infectious diseases, requested by doctors (family and paediatricians) belonging to the primary care health service.
5. Drawing up of recommendations on the appropriate use of ATB in Primary Health care
   Bibliographical review of the scientific literature in bibliographical databases: Medline, Embase, Cochrane Library, Best Evidence and INAHTA.
   Identification and selection of quality surveys that comply with the inclusion criteria previously established in the survey, making a synthesis and presentation in the form of tables of the evidence offered by the relevant surveys.
6. Economic assessment of the consumption of antibiotics
   The total amount consumed in antibiotics during the period studied was calculated. To make a real estimation of the increase in expenditure, current pesetas were adjusted to constant pesetas, using the annual CPIs and taking 1997 as the base year.
   Once the indication-prescription survey had been made, it was decided to estimate what could have been saved, should antibiotics not have been prescribed for viral infections for which there were no instructions to use these.

CONCLUSIONS

The incidence of infectious pathology shows a decrease over recent years which has not had an influence on the consumption of antibiotics, which was stable during the period under study. Nevertheless, the utilisation profile has changed radically. Traditional antibiotics have been replaced by new, wide-spectrum, more costly antibiotics (macrolides, excluding erythromycins, cephalosporins of 2nd and 3rd generation and quinolones). The levels of resistance of the main micro-organisms involved in the most prevalent infections in primary health care, are very high. This seems to confirm the relationship between resistance and the consumption of antibiotics.

The use of antibiotics in mostly viral infectious aetiology processes (colds in the high respiratory tracts, influenza and acute bronchitis) is high. This represents 40% of all antibiotic prescriptions leading to an unnecessary expenditure of over 1,000 million pesetas in the Basque Country.

In those processes in whih ATB treatment is indicated (tonsillitis, otitis, urinary infection, sinusitis, pneumonia, dental infection) when the choice of ATB is inadequate this is at the expense of wise spectrum antibiotics (new macrolides, cephalosporins and amoxicillin-clavulanic acid).

Factors relating to health care professionals such as attitudes and training have more importance in non adequate prescription than the clinical characteristics of patients.

It is necessary to delve further into the prescription/consumption process of ATBs, to explore new aspects not tackled in this survey, such as the attitudes of professionals, the doctor-patient interrelationship, self-medication and the role of pharmacies.

This survey provides keys on which to take action in order to attain a more rational prescription. These include multi-disciplinary collaboration between everyone involved in prescribing ATBs and efficient CMT. It is necessary to take a new look at the current strategies in continuous training in antimicrobial therapy.