Identifying how age and gender influence prescription drug use in a primary health care environment in Catalonia, Spain

Abstract

What is already known about this subject. Knowledge of prescription patterns in primary health care is an important tool in rational drug therapy. Age and gender are the principal determining factors of cost variability between medical practices, due to drug prescriptions. Age and gender are the principal determining factors of cost variability in relation to the therapeutic group. What this study adds. This study provides specific information on the use of drugs in the primary health care environment of the Catalan Health System, and the differences observed are analyzed with respect to age and gender of the population receiving care. The study shows that there is a high prevalence of drugs in the under 5 year old age group, and also in persons over 54 years of age. The variability found in the cost per patient suggests that adjustment should be made for age in practitioners' prescription evaluation procedures in primary health care in Catalonia.

Aims: To determine the prevalence and usage patterns of prescription drugs according to patients' age and gender, and to identify their relative importance in the prescription costs, in primary health care within the Catalan Health Institute.

Methods: This was a cross-sectional study using computerized pharmacy dispensing records for 5 474 274 members registered, during 2002. Twenty age-gender categories were established. Use of a drug group was defined as filling at least one prescription. The variables studied were age, gender, number of prescriptions and net cost. The prevalence of use, the number of prescriptions and cost issued to each age category were reported.

Results: The overall prevalence of drug use was 74.53% (women 80.93%, men 67.84%). This was higher in the group of 0-4 year-olds, and in the >or= 55 year-olds. Age (P < 0.001) produced a statistically more significant effect than gender (P < 0.05). The most used therapeutic groups were analgesics, nonsteroidal anti-inflammatory drugs, antiulcer drugs, anxiolytics, expectorants and mucolytics. The number of prescriptions and costs per patient rose with age and showed great variation in the use of these groups for patients in different age groups. The risk of prescription in women was 23% higher than in men (RR 1.23, 95% CI 1.11, 1.37, P < 0.001).

Conclusions: The majority of subjects were exposed to one or more drugs. The variability in the number of prescriptions and in the prescribing cost per patient between the different age groups suggests that adjustments should be made for age in practitioners' prescription evaluation processes in primary health care in Catalonia.