Preferential prescribing of oral corticosteroids in Irish male asthmatic children

Abstract

Aims

To determine if there is a gender difference in the prescription of oral corticosteroids in asthmatic children (< 15 years).

Methods

8072 asthmatics were identified on the basis that they received a prescription for either an inhaled β-adrenoceptor agonist, an inhaled corticosteroid, inhaled cromoglycate/nedocromil sodium, oral xanthines or leukotriene antagonist. Odds ratios (OR) and 95% confidence intervals (CI) were determined for the different asthma treatments for males compared with females.

Results and conclusions

Male asthmatic children were more likely (OR = 1.37, 95% CI = 1.21,1.55, P < 0.001) to receive a prescription for an oral corticosteroid compared with their female counterparts suggesting a possible increased severity of their condition, rather than a different management of their disease. Male asthmatic children were less likely to be prescribed an antibiotic over the study period (OR = 0.85, 95% CI = 0.77, 0.93, P < 0.001).

Introduction

Oral corticosteroids are commonly used to treat acute exacerbations of asthma. Recently it has been suggested that oral corticosteroids are more likely to be prescribed to adult female asthmatics [1]. Little information is available on such preferential prescribing in asthmatic children. Whilst prescribing for women has been shown to be consistently higher than men, in part attributed to the more frequent use of medical services, there is little evidence to suggest a gender difference regarding such utilization in children. Prescription databases have been used to identify asthmatic patients and study the prescribing trends of asthma medications [2, 3]. We explored a large prescription database to determine if there was a gender difference in the prescription of oral corticosteroids in a younger asthmatic population (aged less than 15 years).

Methods

The General Medical Services (GMS) scheme provides free health service to approximately 31% of the Irish population and is described in detail elsewhere [4]. While the GMS population cannot be regarded as representative of the general population as socially disadvantaged persons, children and the elderly are over represented, however, it comprises approximately a third of the Irish population who receive some 70% of all medicines prescribed in general practice [5] and thus represents a valuable resource for epidemiological purposes. We examined prescription details over the period July to December 1998 from the Eastern Health Board region (population of 333 989) of the GMS. Patients were identified as being asthmatic on the basis that they received a prescription for either an inhaled β-adrenoceptor agonist, inhaled corticosteroids, inhaled cromoglycate/nedocromil, oral xanthines or leukotriene receptor antagonist over the 6 month study period. Patients who received a prescription for an oral corticosteroids (prednisolone or prednisone) were identified within this patient group. Logistic regression analysis was used to determine odd ratios for the different asthma treatments for males compared with females. In addition we determined an odds ratio of antibiotic use by males compared with females in this asthmatic group.

Results

8072 asthmatic patients (M : F, 4651 : 3421) in the age group 0–15 years were identified from the prescription database from a total population of 87,980 (M : F 44 822 : 43158) eligible children. The odds ratios (OR) for the different asthma therapies in children are shown in Table 1. Male asthmatic children were more likely to receive a prescription for an oral corticosteroid compared with their female counterparts. This effect was more significant at younger age groups (OR = 1.66, 95% CI 1.31,2.1, P < 0.001 for children aged 0–4 years, OR = 1.31, 95% CI 1.1,1.57, P = 0.002 for children aged 5–11 years) than for older children (12–15 years) where there was no statistically significant difference. A similar but less pronounced preferential prescribing was seen with inhaled steroids, xanthines and leukotriene antagonists. Male asthmatic children were less likely to be prescribed an antibiotic over the study period. This preferential prescribing was more marked for older ages (OR = 0.75, 95% CI 0.66, 0.86, P < 0.001, for children aged 5–11 years, OR = 0.77, 95% CI 0.66, 0.9, P = 0.0015 for children aged 11–15 years) than for children aged less than 4 years where there was no significant difference.

Table 1.

Numbers of male and female asthmatics and odds ratios for prescribed asthma drugs and antibiotics over the study period

Therapy*	Male	Female	Odds ratio	95% confidence interval	P value
Inhaled β-adrenoceptor agonist	4132	3039	1.0	0.87, 1.15	NS
Oral corticosteroid	864	488	1.37	1.21, 1.55	< 0.001
Inhaled corticosteroid	2679	1855	1.15	1.05, 1.25	0.0025
Inhaled cromoglycate/nedocromil	203	127	1.2	0.95, 1.49	NS
Xanthines	374	222	1.22	0.95, 1.49	0.02
Leukotriene antagonists	9	6	1.19	0.4, 3.3	NS
Antibiotic	2873	2241	0.85	0.77, 0.93	< 0.001

NS: Not statistically significant.

^*The seven therapies are not mutually exclusive.

The ratio of the number of daily defined doses of inhaled corticosteroid to inhaled bronchodilator was 0.64 in those asthmatics who received an oral corticosteroid compared with a ratio of 0.54 in those asthmatics who did not receive a prescription for a corticosteroid. The daily defined dose is the assumed average daily maintenance dose for a drug when used for its main indication in adults [6] and whilst not available for children it gives a more accurate assessment of volume of use than that obtained from the number of prescription items dispensed [7].

Discussion

Gender has a significant relationship regarding hospital admissions and prevalence of self-reported asthma in adults [8]. A study of asthmatic patients has shown both all-cause and respiratory mortality to be particularly raised in women with asthma [9]. Female gender and the number of positive skin tests have been suggested as the best independent correlates to the asthma severity score in adolescents aged 13–18 years [10]. The greatest incidence of childhood asthma is among males under 5 years, with decreasing numbers of new cases with advancing age. In children without a history of atopy or family history of allergy or asthma, wheezing often relates to infections and environmental smoke exposure [11]. A higher hospitalization rate of asthma in boys has been noted with the greatest gender difference observed among children who were less than 24 months old [12]. In a survey of hospitalized asthmatics, boys were more likely to have a higher severity of asthma [13]. Assessing differences in asthma severity is difficult as commonly used measures of severity (such as the number of hospitalizations, amount of asthma medications used) are highly influenced by social and economic factors such as access to health care, quality of health care, referral to specialist clinics and health care seeking behaviour. Whilst urban deprivation is associated with increased hospitalization rates for asthmatic children, these increased rates have been shown to be the result of an increased need rather than excess utilization of health services [12]. Thus any differences in the use of antiasthmatic medications are likely to reflect differences in the underlying condition.

In Ireland the prevalence of asthma among school children aged 13–14 years has been reported as 17.8% for males and 12.9% for females [14]. A study undertaken 2 years previously had reported a prevalence of 14.8% and 8.35%, respectively. In addition the prevalence of subjects with wheeze in the previous 12 months was higher in boys [15]. A survey of paediatric hospital admissions also identified a male preponderance [16]. This prescription-based study indicates a lower overall prevalence of 10.4% and 7.9% for male and female asthmatic children, respectively. This may indicate either under treatment, poor compliance with medications or the fact that mild asthmatics did not require a prescription for their medication over the study period.

When examining prescription databases for adult asthmatics a certain degree of overlap may occur between asthma and chronic obstructive airways disease when diseases are identified by drug therapy. However this overlap is less likely to occur when examining paediatric prescriptions.

Our results indicate that male asthmatic children are more likely to be prescribed an oral corticosteroid compared with their female counterparts, indicating a possible increased severity of their condition rather than a different management of their disease. The higher ratio of inhaled corticosteroid to inhaled bronchodilator in asthmatics who received a prescription for a corticosteroid may indicate a more targeted approach to the treatment of those with a higher perceived severity of asthma. There was little gender difference in the prescribing of other asthma medications. Of interest male asthmatic children were less likely to be prescribed an antibiotic over the study period. Within this age group overall we found no significant gender difference in antibiotic prescribing. A possible reason for this differential prescribing pattern in male asthmatics may be that such patients are more likely to be treated as noninfective exacerbations of asthma by their general practitioner. Alternatively the greater use of oral corticosteroids in male asthmatic children may be the result of an under treatment of infective exacerbations with antibiotics. In conclusion gender differences in the use of asthma drugs may be age dependent.