Objective: To examine the patterns of respiratory drugs use in the Lombardy region of Italy, and to quantify the period prevalence of different drug-dose combinations defined by reference to international guidelines for prescription in asthma and chronic obstructive pulmonary disease.
Design: Analysis of records from an anonymised population-based database of dispensed prescriptions.
Setting: Lombardy, 1995-1997.
Methods: Analyses were made of prescription records of patients who had at least one respiratory drug dispensed during the study period. Prescriptions for the same individual were linked using a unique identifier.
Main outcomes: Number of patients using respiratory drugs; number of visits to the pharmacy; defined daily doses.
Main results: 1,387,004 or 15.5% of the resident Lombardy population had at least one dispensed prescription of a respiratory drug in the three years of study. The annual percentage increased from 6.6% in 1995 to 7.9% in 1997. 808,786 patients (58.3% of respiratory drug users) had only one visit to the pharmacy during this period, while the 25.1% of respiratory drug-user (3.9% of the resident population) who had three or more visits to the pharmacy in three years, accounted for 86.1% of all respiratory drug use in terms of defined daily doses. When combinations of prescribed drugs were examined in the light of published guidelines, we estimated that <2.8%> of the population had patterns of drug prescription appropriate for mild intermittent or persistent forms of asthma/chronic obstructive pulmonary disease, and <1.1%> had prescription patterns appropriate for moderate or severe disease.
Conclusions: The definition of specific drug use patterns by individual can provide prevalence measures that are broad proxies for varying categories of respiratory disease. However, a very high proportion of people who receive respiratory drugs do so for one-off or very infrequent episodes of illness. Analysis of the infrequent and more regular users of respiratory drugs may be useful for comparative research.