Asthma medications and disease exacerbations: an epidemiological study as a method for asthma surveillance

Use of a total traffic count metric to investigate the impact of roadways on asthma severity: a case-control study

BACKGROUND

This study had two principal objectives: (i) to investigate the relationship between asthma severity and proximity to major roadways in Perth, Western Australia; (ii) to demonstrate a more accurate method of exposure assessment for traffic pollutants using an innovative GIS-based measure that fully integrates all traffic densities around subject residences.

METHODS

We conducted a spatial case-control study, in which 'cases' were defined as individuals aged under 19 years of age with more severe asthma (defined here as two or more emergency department contacts with asthma in a defined 5-year period) versus age- and gender-matched 'controls' with less severe asthma (defined here as one emergency department contact for asthma). Traffic exposures were measured using a GIS-based approach to determine the lengths of the roads falling within a buffer area, and then multiplying them by their respective traffic counts.

RESULTS

We examined the spatial relationship between emergency department contacts for asthma at three different buffer sizes: 50 metres, 100 metres and 150 metres. No effect was noted for the 50 metre buffer (OR = 1.07; 95% CI: 0.91-1.26), but elevated odds ratios were observed with for crude (unadjusted) estimates OR = 1.21 (95% CI: 1.00-1.46) for 100 metre buffers and OR = 1.25 (95% CI: 1.02-1.54) for 150 metre buffers. For adjusted risk estimates, only the 150 metre buffer yielded a statistically significant finding (OR = 1.24; 95% CI:1.00-1.52).

CONCLUSIONS

Our study revealed a significant 24% increase in the risk of experiencing multiple emergency department contacts for asthma for every log-unit of traffic exposure. This study provides support for the hypothesis that traffic related air pollution increases the frequency of health service contacts for asthma. This study used advanced GIS techniques to establish traffic-weighted buffer zones around the geocoded residential location of subjects to provide an accurate assessment of exposure to traffic emissions, thereby providing a quantification of the ranges over which pollutants may exert a health effect.

Design of cohort studies in chronic diseases using routinely collected databases when a prescription is used as surrogate outcome

Background

There has been little research on design of studies based on routinely collected data when the clinical endpoint of interest is not recorded, but can be inferred from a prescription. This often happens when exploring the effect of a drug on chronic diseases. Using the LifeLink claims database in studying the possible anti-inflammatory effects of statins in rheumatoid arthritis (RA), oral steroids (OS) were treated as surrogate of inflammatory flare-ups. We compared two cohort study designs, the first using time to event outcomes and the second using quantitative amount of the surrogate.

Methods

RA patients were extracted from the LifeLink database. In the first study, patients were split into two sub-cohorts based on whether they were using OS within a specified time window of the RA index date (first record of RA). Using Cox models we evaluated the association between time-varying exposure to statins and (i) initiation of OS therapy in the non-users of OS at RA index date and (ii) cessation of OS therapy in the users of OS at RA index date. In the second study, we matched new statin users to non users on age and sex. Zero inflated negative binomial models were used to contrast the number of days' prescriptions of OS in the year following date of statin initiation for the two exposure groups.

Results

In the unmatched study, the statin exposure hazard ratio (HR) of initiating OS in the 31451 non-users of OS at RA index date was 0.96(95% CI 0.9,1.1) and the statin exposure HR of cessation of OS therapy in the 6026 users of OS therapy at RA index date was 0.95 (0.87,1.05). In the matched cohort of 6288 RA patients the statin exposure rate ratio for duration on OS therapy was 0.88(0.76,1.02). There was digit preference for outcomes in multiples of 7 and 30 days.

Conclusions

The 'time to event' study design was preferable because it better exploits information on all available patients and provides a degree of robustness toward confounding. We found no convincing evidence that statins reduce inflammation in RA patients.

Measuring exacerbations in obstructive lung disease

PURPOSE

Using hospitalization always has been seen as a solid measurement for exacerbation in pharmacoepidemiology, but might lead to an underestimation of disease exacerbation because of a trend towards outpatient care. The aim of this study was to quantify the incidence of different exacerbation markers in obstructive lung disease and to identify predictors for these exacerbation markers.

METHODS

We conducted a cohort study using the PHARMO record linkage system, including demographic details and complete medication histories of more than two million community-dwelling residents in the Netherlands from 1985 onwards. Eligible patients were adult users of inhaled corticosteroids (ICS). Outcome parameters were hospitalization and short courses of systemic corticosteroids. Patients were allowed to have multiple exacerbations during follow-up.

RESULTS

We identified 5327 patients. During follow-up, 8635 exacerbations occurred in 2332 patients with a trend in time towards treating exacerbations out of the hospital (p-value 0.003). Of all patients with exacerbations, 73% was not hospitalized during follow-up. Exacerbations were associated with high-dose ICS use (adjusted RR 1.4; 95% CI 1.2-1.7) and chronic systemic corticosteroid use (adjusted RR 1.9; 95%CI 1.6-2.2).

CONCLUSIONS

Using hospitalization only as exacerbation marker leads to underestimating the exacerbation rate, because of exacerbation treatment out of the hospital. Patients with obstructive lung disease using chronic systemic corticosteroids or high-dose ICS use are more prone to exacerbations. This implies that these patients should be monitored carefully to prevent recurrent exacerbations which are detrimental for their prognosis and quality of life.

Identification of exacerbations in obstructive lung disease through biomarkers

Inflammation has been identified as an important factor for disease exacerbation in obstructive lung disease. In this study, we used neutrophil and eosinophil counts as biomarkers for exacerbation in obstructive lung disease. We conducted a case-control study within a cohort of patients frequenting an outpatient clinic of Respiratory Medicine using data from the Utrecht Patient Oriented Database (UPOD). Cases were patients with a hospital admission for obstructive lung disease in 2005. For each case, one control patient was sampled from the same study base. We identified 143 cases (118 patients with chronic obstructive pulmonary disease and 25 asthma patients) and 143 controls. Admission was associated with both neutrophilia (adjusted odds ratio (OR) 4.3; 95% confidence interval (CI) 2.2-8.5), and eosinophilia (adjusted OR 2.6; 95% CI 1.1-6.2). The association with eosinophilia was only seen in asthma patients. In conclusion, neutrophil and eosinophil counts seem to be useful biomarkers for identifying exacerbations in pharmacoepidemiological studies on obstructive lung disease.

Medication changes prior to hospitalization for obstructive lung disease: a case-crossover study

BACKGROUND

Hospitalizations have always been seen as a solid outcome parameter in pharmacoepidemiology. However, the period leading to hospitalization and prehospital management of the patient are equally important.

OBJECTIVE

To evaluate medication changes in the period prior to hospitalization for obstructive lung disease and to quantify the association between medication use and the risk of hospitalization.

METHODS

We conducted a case-crossover study using the PHARMO record linkage system, which contains drug dispensing data from community pharmacies and hospital admission data. Patients included in the study were adults hospitalized for obstructive lung disease between 2005 and 2007. The index date of the case period was the date of hospitalization, and control moments were set at 3, 6, 9, and 12 months before admission. For each patient, all prescriptions prior to the date of hospitalization were identified. Medication use was ascertained in a 90-day time window prior to each case or control moment.

RESULTS

We identified 1481 patients who were hospitalized for obstructive lung disease. It appeared that respiratory medication use increased in the 90 days prior to hospitalization. Hospitalization was associated with the use of 3 or more respiratory drugs (OR 2.2; 95% CI 1.8 to 2.8), systemic glucocorticoids (OR 4.5; 95% CI 3.8 to 5.4), and antibiotics (OR 3.1; 95% CI 2.7 to 3.6).

CONCLUSIONS

The use of systemic glucocorticoids, antibiotics, and other respiratory drugs increased prior to hospitalization for obstructive lung disease. These results could be indicative of the development and/or treatment of an exacerbation. There is a need for markers to detect exacerbations in an early phase in order to start treatment as early as possible and possibly prevent hospitalizations for obstructive lung disease.

Effects of corticosteroid use on readmission in obstructive lung disease

OBJECTIVE

Obstructive lung disease is a leading cause of morbidity and mortality worldwide. Some patients are readmitted, but currently predicting parameters for identifying these patients are lacking. The aim of this study was to quantify the incidence of readmission in chronic obstructive lung disease and to identify determinants for hospital readmission.

METHODS

We conducted a cohort study using the PHARMO record linkage system, including demographic details and complete medication histories of more than two million community-dwelling residents in the Netherlands from 1985 onwards. Eligible patients were adult users of inhaled corticosteroids (ICS) with an admission for obstructive lung disease. The outcome parameter was readmission within a follow-up period of one year.

RESULTS

We identified 605 ICS users with an admission for chronic obstructive lung disease, 132 of these patients were readmitted. Readmission was associated with a high Chronic Disease Score (adjusted HR 2.4; 95% CI 1.1-5.3). Patients using short courses of systemic corticosteroids only (adjusted HR 0.5; 95% CI 0.4-0.8) or combined with antibiotics (adjusted HR 0.4; 95% CI 0.2-0.6) were at decreased risk of readmission. The effect of high-dose ICS use varied over time.

CONCLUSIONS

Treatment of exacerbations out of the hospital was associated with a decreased risk of readmission, while patients with multiple chronic diseases are at increased risk of readmission for obstructive lung disease. These patients should be educated and should be invited to consultation more often to be able to detect exacerbation in an early phase and start treatment as early as possible.

Use of inhaled corticosteroids and the risk of non-fatal acute myocardial infarction

BACKGROUND

Use of inhaled corticosteroids may reduce the risk of acute myocardial infarction (MI) through reductions in systemic inflammation and C-reactive protein.

OBJECTIVES

To examine the association between the use of inhaled corticosteroids and the risk of non-fatal acute MI.

METHODS

In the Dutch PHARMO record linkage system database, we conducted a case-control study (2476 MI cases), nested in a cohort of antihypertensive drug users. The use of inhaled corticosteroids 100 days before the index date was compared with never use. We adjusted the analyses for the severity of the underlying respiratory disease and general drug and disease history.

RESULTS

We found that the use of inhaled corticosteroids was not associated with a decreased risk of non-fatal MI in antihypertensive drug users after adjustment for the underlying respiratory disease severity, adjusted odds ratio (OR) 1.24, 95% confidence interval (CI) 0.97-1.57. A higher daily dose (adjusted OR 1.82, 95% CI 0.80-4.13) and longer duration of use (adjusted OR 1.28, 95% CI 0.90-1.81) were not associated with a decreased risk of non-fatal MI. An inhaled corticosteroid dispensing in the 30 days before the index date was not protective but resulted in a 1.7-fold increased risk of non-fatal MI.

CONCLUSION

Our results do not support the hypothesis that inhaled corticosteroids protect against the risk of non-fatal MI by a reduction of systemic inflammation.

Use of beta2 agonists and risk of acute myocardial infarction in patients with hypertension

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

* Use of beta(2) agonists has been associated with tachycardia, an abnormal ECG and atrial fibrillation. * Previous observational studies of the association between use of beta(2) agonists and the risk of acute myocardial infarction (MI) have demonstrated conflicting results. * Instead of a causal effect, the positive association between beta(2) agonist use and MI may be explained by latent ischaemic heart disease, which has symptoms that appear similar to respiratory complaints in chronic obstructive pulmonary disease.

WHAT THIS STUDY ADDS

* The majority of beta(2) agonist users in our study population did not have an increased risk of nonfatal acute MI. * Only patients with ischaemic heart disease and who had recently started beta(2) agonists had an increased risk of acute MI. * It is likely that this increased risk was related to latent cardiovascular disease rather than direct effects of beta(2) agonists.

AIM

Observational retrospective studies of the association between use of beta(2) agonists and the risk of acute myocardial infarction (MI) have demonstrated conflicting results, particularly among first-time users. The aim of this study was to examine the association between beta(2) agonist use and first nonfatal acute MI.

METHODS

We conducted a case-control study (2476 cases) nested in a cohort of antihypertensive drug users in the Dutch PHARMO RLS database. PHARMO RLS consists of drug dispensing linked to the national hospitalizations register. Each case of nonfatal acute MI was matched with up to 12 control patients by gender, age and region. Drug and disease history and the severity of the underlying respiratory disease were adjusted for.

RESULTS

Risk of acute MI was increased in current beta(2) agonist users [crude odds ratio (OR) 1.36, 95% confidence interval (CI) 1.15, 1.61]. However, this excess risk was reduced after adjustment for severity of asthma and chronic obstructive pulmonary disease (adjusted OR 1.18, 95% CI 0.93, 1.49). The risk was highest in patients with ischaemic heart disease and low cumulative dose of beta(2) agonists (adjusted OR 2.47, 95% CI 1.60, 3.82).

CONCLUSION

Most users of beta(2) agonists did not have an increased risk of acute MI. Only patients with ischaemic heart disease with low cumulative exposure to beta(2) agonists had an increased risk of acute MI. It is likely that this increased risk was related to latent cardiovascular disease rather than to the direct effects of beta(2) agonists.

Use of beta-2 agonists and risk of hip/femur fracture: a population-based case-control study

INTRODUCTION

Administration of beta-2 agonists decreased bone mineral density in rats. But the association between bronchodilators and fracture risk has not been studied in humans.

OBJECTIVES

To examine the association between use of beta-2 agonists and risk of hip/femur fracture.

METHODS

We conducted a population-based case-control study (6763 cases) in the Dutch PHARMO database. Current beta-2 agonist use was compared to never use. We adjusted for severity of the underlying respiratory disease and disease and drug history.

RESULTS

A hospitalisation for asthma/COPD in the year before index date increased risk of hip/femur fracture: crude OR 2.17 (95% CI, 1.41-3.34). Patients using higher doses of beta-2 agonists had increased risk of hip/femur fracture: crude OR 1.94 (95% CI, 1.41-2.66) for daily dosages of >or=1600 microg albuterol equivalent. The excess fracture risk reduced after adjustment for disease severity (1.46; 95% CI, 1.02-2.08) and after exclusion of oral glucocorticoid users (1.31; 95% CI, 0.80-2.15). Risk of hip/femur fracture was similar between users of beta-2 agonists, inhaled glucocorticoids and anticholinergics.

CONCLUSION

We found increases in the risk of hip/femur fracture in patients using higher doses of beta-2 agonists. However, the excess risk of hip/femur fracture substantially reduced after exclusion of oral glucocorticoid users and after adjustment for the underlying disease. Risk of hip/femur fracture was similar between users of beta-2 agonists, inhaled glucocorticoids and anticholinergics. The severity of the underlying disease, rather than the use of beta-2 agonists, may play an important role in the aetiology of hip/femur fractures in patients using beta-2 agonists.

Use of inhaled and oral glucocorticoids, severity of inflammatory disease and risk of hip/femur fracture: a population-based case-control study

BACKGROUND

Patients using higher dosages of inhaled or oral glucocorticoids (GCs) have an increased risk of hip/femur fractures. The role of the underlying disease in the aetiology of this increased risk has not been widely studied.

OBJECTIVE

To evaluate the contribution of the underlying disease to the risk of hip/femur fracture in patients using inhaled or oral GCs.

DESIGN AND SUBJECTS

A case-control study within the Dutch PHARMO-RLS database was conducted. Cases (n = 6763) were adult patients with a first hip/femur fracture during enrolment. Each case was matched to four controls by age, gender and region.

RESULTS

The risk of hip/femur fracture increased with current use of inhaled GCs (crude OR 1.30, 95% CI:1.16-1.47) and with current use of oral GCs (crude OR 1.66, 95% CI: 1.46-1.90). After adjustment for disease severity, the risk of hip/femur fracture was no longer statistically significantly increased in inhaled GC users (adjusted OR 1.08, 95% CI: 0.91-1.27), whilst it remained elevated in oral GC users (adjusted OR 1.43, 95% CI: 1.22-1.67). Patients using inhaled GCs without any exposure to oral GCs had no increased risk of fracture (adjusted OR 0.98, 95% CI: 0.79-1.22).

CONCLUSION

Inhaled GC users had no increased risk of femur/hip fracture after adjustment for underlying disease severity. Our data suggest that, even at higher dosages, inhaled GC use is not an independent risk factor for fracture. In contrast, oral GC use was associated with an increased risk of fracture, which was not fully explained by the underlying disease severity.

Reconcilable differences: a cross-sectional study of the relationship between socioeconomic status and the magnitude of short-acting beta-agonist use in asthma

STUDY OBJECTIVE

To assess the association between socioeconomic status (SES) and short-acting (SA) beta-agonist use, controlling for asthma severity.

DESIGN

Cross-sectional study.

SETTING

Vancouver, BC, Canada.

PARTICIPANTS

Two hundred two asthmatics between 19 years and 50 years of age and residing in the greater Vancouver regional district.

MEASUREMENTS

The quantity of SA beta-agonist used in the previous year was collected by self-report; pulmonary function and beta-receptor genotype were measured on each participant. SES was measured at both the individual and population levels. Five methods of adjustment for asthma severity were used, as follows: the Canadian Asthma Consensus Guidelines, three previously developed asthma-severity scores, and forward stepwise multiple regression modeling. Polychotomous logistic regression was used to assess all relationships.

RESULTS

Independent of the method used to measure SES or adjust for asthma severity, lower SES was consistently and significantly associated with the use of greater amounts of SA beta-agonist. Adjusting for severity using the multivariate model explained the most variance of SA beta-agonist use (R(2) adjusted, 0.35 to 0.37). In this model, social assistance recipients were more likely to use greater amounts of SA beta-agonist (odds ratio [OR], 3.4; 95% confidence interval [CI], 1.7 to 6.5). An inverse relationship between SA beta-agonist use and both annual household income (> $50,000; OR, 0.28; 95% CI, 0.13 to 0.60; and $20,000 to $50,000; OR, 0.44; 95% CI, 0.21 to 0.96; relative to <$20,000) and education (completing a bachelor's degree vs no formal education; OR, 0.25; 95% CI, 0.14 to 0.71). Participants living in a neighborhood with higher median household income (OR, 0.91; 95% CI, 0.84 to 0.98 per $1,000 increase) or a higher prevalence of having attained a bachelor's degree (OR, 0.96; 95% CI, 0.84 to 0.98 per 1% increase) were also less likely use greater amounts of SA beta-agonist. Results were consistent for neighborhood unemployment rate.

CONCLUSIONS

The social gradient in asthma-related outcomes may be at least partially attributable to poorer asthma control in lower-SES asthmatics.

An Internet survey of asthma treatment

The aim of this investigation was to study pharmacological treatment in relation to asthma severity among patients visiting an asthma web site on the Internet. The study comprised 650 subjects from 30 countries with self-reported asthma that participated in an Internet based patient survey. The survey was posted on the web site Asthma Information Centre (www.mdnet.de). Moderate or severe night cough or wheezing was reported by 43% and activity limitation by 55% of the asthmatics. Short-acting beta-agonists were used by 67% and inhaled steroids by 59%. The use of short-acting beta-agonists decreased with age, whereas the use of inhaled steroids, long-acting beta-agonists and antileukotrienes was lowest in the youngest (0-20 years) and highest age groups (> 60 years). The use of short-acting beta-agonists increased, and the use of inhaled steroids decreased with the severity of nocturnal symptoms (p < 0.01). Side effects were most often reported for oral beta-agonists (42%) and least often for antileukotrienes (9%). We conclude that despite problems with selection and external validity, an online asthma survey produces results that agree highly with more resource-demanding surveys. We find that many asthmatics have a low level of asthma control, and the survey indicates that underuse of inhaled steroids is one of the reasons why the goals set up in asthma guidelines so far have not been reached.

Adverse effects of beta-agonists: are they clinically relevant?

Inhaled beta(2)-adrenoceptor agonists (beta(2)-agonists) are the most commonly used asthma medications in many Western countries. Minor adverse effects such as palpitations, tremor, headache and metabolic effects are predictable and dose related. Time series studies suggested an association between the relatively nonselective beta-agonist fenoterol and asthma deaths. Three case-control studies confirmed that among patients prescribed fenoterol, the risk of death was significantly elevated even after controlling for the severity of asthma. The Saskatchewan study not only found an increased risk of death among patients dispensed fenoterol, but also suggested this might be a class effect of beta(2)-agonists. However, in subsequent studies, the long-acting beta(2)-agonist salmeterol was not associated with increased asthma mortality. In a case-control study blood albuterol (salbutamol) concentrations were found to be 2.5 times higher among patients who died of asthma compared with controls. It is speculated that such toxic concentrations could cause tachyarrhythmias under conditions of hypoxia and hypokalemia. The risk of asthma exacerbations and near-fatal attacks may also be increased among patients dispensed fenoterol, but this association may be largely due to confounding by severity. Although salmeterol does not appear to increase the risk of near-fatal attacks, there is a consistent association with the use of nebulized beta(2)-agonists. Nebulized and oral beta(2)-agonists are also associated with an increased risk of cardiovascular death, ischemic heart disease and cardiac failure. Caution should be exercised when first prescribing a beta-agonist for patients with cardiovascular disease. A potential mechanism for adverse effects with regular use of beta(2)-agonists is tachyphylaxis. Tachyphylaxis to the bronchodilator effects of long-acting beta(2)-agonists can occur, but has been consistently demonstrated only for formoterol (eformoterol) a full agonist, rather than salmeterol, a partial agonist. Tachyphylaxis to protection against induced bronchospasm occurs with both full and partial beta(2)-agonists, and probably within a matter of days at most. Underlying airway responsiveness to directly acting bronchoconstricting agents is not increased when the bronchodilator effect of the regular beta(2)-agonist has been allowed to wear off, although there may be an increase in responsiveness to indirectly acting agents. While there has been speculation that underlying airway inflammation in asthma may be made worse by regular use of short-acting beta(2)-agonists, in contradistinction, a number of studies have shown that long-acting beta(2)-agonists have positive anti-inflammatory effects. An Australian Cochrane Airways Group systematic review of the randomized, controlled trials of short-acting beta-agonists found only minimal and clinically unimportant differences between regular use and use as needed. Regular short-acting treatment was better than placebo. However, a subsequent systematic review has found that regular use of long-acting beta-agonists had significant advantages over regular use of short-acting beta-agonists. More studies and data are needed on the regular use of beta(2)-agonists in patients not taking inhaled corticosteroids, and in potentially vulnerable groups, such as the elderly and those with particular genotypes for the beta-receptor, who might be more prone to adverse effects.

The use of anti-asthmatic medications among pediatric patients in Taiwan

PURPOSE

To describe the use of anti-asthma drugs in Taiwanese pediatric patients.

METHODS

Using the data from the database of Bureau of National Health Insurance, we analyze the patterns and extent of medication use among asthma patients less than 18 years old. Drugs were classified according to the Anatomical Therapeutic Chemical (ATC) Classification system.

RESULTS

Data on a total of 2,90,467 children were included in the study. Overall, patients were treated more frequently with oral medications. 69.43 and 40.24% of patients were using oral beta-agonists (OBAs) and methylxanthines respectively. Monotherapy with OBAs was the most popular regimen, accounting for 13.70% of the total prescriptions studied. Only 6.70% of patients were taking inhaled corticosteroids (ICSs). During the studied period, users of ICSs were using an average of 1.65 canisters.

CONCLUSIONS

The current practices of asthma management in Taiwan fall short of the goals stated in international guidelines. Anti-inflammatory agents were being underused in Taiwanese pediatric patients.

Patterns of inhaled asthma medication use: a 3-year longitudinal analysis of prescription claims data from British Columbia, Canada

STUDY OBJECTIVES

To assess trends in asthma management and to identify factors associated with increasing short-acting (SA) beta-agonist utilization in British Columbia using administrative prescription data.

DESIGN

A retrospective cohort analysis.

SETTING

All patients between 13 and 50 years of age who had received at least one prescription for a SA beta-agonist covered by BC Pharmacare between January 1, 1996, and December 31, 1998.

METHODS

Cross-sectional analysis of all patients, and longitudinal analyses only of patients who had received at least one SA beta-agonist prescription in each of the 3 years. Trends in asthma medication use over time were evaluated using repeated-measures Mantel-Haenszel tests. Multiple logistic regression was used to identify factors associated with increasing SA beta-agonist use.

RESULTS

A total of 78,758 patients were included in the cohort. No decrease in the annual prevalence of receiving more than four canisters per year of a SA beta-agonist was identified between 1996 and 1998. A total of 12,844 patients filled at least one SA beta-agonist prescription each year. Time-trend analysis showed an overall increasing probability of not receiving an inhaled corticosteroid (ICS) agent in this population (p = 0.002). In patients exhibiting low SA beta-agonist use, > 18 years of age (adjusted odds ratio [OR], 1.5), male gender (adjusted OR, 1.7), and in receipt of social assistance (adjusted OR, 2.3) were associated with receiving increasing amounts of SA beta-agonist agents over the 3 years. In patients with a high degree of use of SA beta-agonists, only the receipt of social assistance (adjusted OR, 1.3) was significantly associated with increasing use.

CONCLUSIONS

Despite the development and dissemination of asthma management guidelines, there was no trend toward decreasing SA beta-agonist use. An unexpected trend toward decreasing ICS utilization was identified. Receiving social assistance was a risk factor for increasing SA beta-agonist use, independent of baseline utilization.

Level of control and hospital contacts in persistent asthma

The purpose of this study was to estimate relationships between asthma control and hospital contacts (visits to emergency rooms and hospitalizations) in a group of patients suffering from persistent asthma, after adjustment for prior use of inhaled corticosteroids. A computerized family practice database was used to identify patients (aged 6-50 years) with persistent asthma who received asthma therapy from January 1995. The database provided information on patient demographics and drug therapy. Asthma control was estimated by a survey of patients at the end of a 12-month study period. Frequency of hospital contacts during the study period was related to demographics, asthma control, and prescribed doses of inhaled corticosteroids during a prestudy period. Review of computerized medical files of 497 family practice physicians identified 1,966 patients with persistent asthma who met the study criteria. Of these patients, 1,251 completed the survey (63.6%). Asthma control was assessed in 1,130 patients; it was moderate or poor in 42% of the cases. During the 12-month study period, 14.8% of patients reported at least one hospital contact. The level of asthma control was significantly (p < 0.001) associated with hospital contacts. The odds ratio (OR) for hospital contact for good and poor asthma control was 0.5 (95% confidence interval [CI] 0.2-0.7) and 2.2 (95% CI 1.2-4.4), respectively. Asthma control was related to hospital contacts independently of use of inhaled corticosteroids before the study period. Overall, control of asthma was not optimal in this population. The occurrence of hospital contacts was closely related with the level of control. This association was independent of the dose of inhaled corticosteroids prescribed before the study, suggesting that in asthma, hospital contacts are primarily related to the level of control experienced by the patients.

Requests for repeat medication prescriptions and frequency of acute episodes in asthma patients

This study was conducted to determine if suboptimal use of inhaled steroid and over-reliance on bronchodilator medication to control asthma symptoms is associated with higher risk of acute asthma episodes. Details of repeat prescriptions for medication and use of health services over 12 months were collected for 754 adult outpatients with asthma; all were prescribed inhaled corticosteroid. Patients who requested less than five prescriptions per year were considered suboptimal users. Patients who requested seven or more bronchodilator prescriptions and less than five inhaled steroid prescriptions had significantly more family physician consultations for asthma episodes (p < 0.05), more hospital admissions (p < 0.05), and more disturbed nights in the week before hospital or family physician review (p < 0.05). Some patients with more severe asthma put themselves at risk by relying on bronchodilator medication rather than regular inhaled steroid for asthma control. Among patients who were low bronchodilator users, those who requested few inhaled steroid prescriptions were younger and more anxious but did not have an increased risk of acute asthma episodes.

Asthma exacerbations during first therapy with long acting beta 2-agonists

Long-acting beta 2-agonists (LBA) have become an important therapeutic strategy in the treatment of asthma. There is, however, debate whether LBA increase the risk of asthma exacerbations (AE). We studied whether the risk of AE was increased in patients starting LBA therapy and whether the risk was associated with severity. Patients, aged 5-49 years, who were firstly prescribed LBA between 1992 and 1995, and who had at least two consecutive prescriptions of LBA, were selected from the PHARMO-RLS database. The exposure period was the interval between the first and last dispensing of the first exposure episode. The year before the onset was the control period. Single short courses of oral glucocorticosteroids or antibiotics were used as proxy indicators for AE. Severity indicators, assessed in the 6 months before initiation of LBA, were used to classify patients' severity. A total of 788 patients met the inclusion criteria (men: 45.1%, median age: 35). The incidence rate of AE increased significantly (p < 0.001) with severity from 1.7 to 2.4 and 1.1 to 2.7 AE per person year in index and control period, respectively. The risk was merely elevated among patients who start LBA therapy without being treated with other anti-asthma drugs before (RR 1.4, 95% CI 1.0-2.2). First starters of LBA showed no overall change in incidence of AE when compared with the year before starting treatment. A total of 6.9% of patients used LBA as step-one therapy. These patients suffer, in contrast to the whole population, a 40% increased risk of having AE. Although this could be due to confounding, we recommend being reluctant to prescribe LBA to patients who have not been treated before with other anti-asthma drugs.

Proventil HFA and ventolin have similar safety profiles during regular use

OBJECTIVE

As a secondary objective to a long-term study evaluating the bronchodilator effectiveness of Proventil HFA (albuterol), to assess the safety of Proventil HFA, Ventolin, and hydrofluoroalkane 134a (HFA-134a) placebo over 12 weeks of regular dosing.

DESIGN

Randomized, double-blind, double-dummy parallel group, placebo-controlled, multicenter trial of asthmatics requiring inhaled beta-adrenergic bronchodilators for symptom control.

INTERVENTIONS

Treatment with Proventil HFA, Ventolin, or HFA-134a placebo, qid, for 12 weeks.

MEASUREMENTS

Adverse events were reviewed at biweekly clinic visits. Between clinic visits, patients recorded morning and evening peak expiratory flow (PEF), asthma symptom and nighttime asthma sleep disturbance scores, and use of rescue beta-adrenergic bronchodilator on diary cards daily. Investigators provided a global assessment of asthma control at weeks 0, 4, 8, and 12. Vital signs were recorded over 6 h after dosing with study drug at weeks 0, 4, 8, and 12. Standard laboratory tests, CBC count, serum chemistries, and urinalysis were obtained at study start and end.

RESULTS

Adverse event reporting rates were similar for the three treatment groups. The morning PEF tended to be lower for the Proventil HFA and Ventolin groups than the HFA-134a placebo group, but the evening PEF tended to be higher for the active treatment groups. Daytime asthma symptom scores tended to be lower (better) with active treatment than placebo, but nighttime asthma sleep disturbance scores were similar for all three treatment groups. Use of Ventolin Rotacaps as rescue medication was significantly greater for the HFA-134a placebo group than the Proventil HFA and Ventolin groups. Diary card data did not change within groups over time. Investigator global assessments of asthma scores clustered between fair and good for all three treatment groups throughout the study. Changes in heart rate and BP were small after dosing with study drug and tended to be similar for the active treatments and HFA-134a placebo groups. No clinically meaningful changes in results of standard laboratory tests were found in any treatment group during this study.

CONCLUSIONS

Proventil HFA had a similar safety profile as Ventolin during regular use. A dosage of 16 puffs per day of propellant HFA-134a was well tolerated by asthmatics. Regular use of either Proventil HFA or Ventolin did not cause asthma control to deteriorate.

Assessing asthma management from interviews of patients and family physicians

Directed self-care is recommended in asthma. Adequate patient education and follow-up are nevertheless necessary to optimize outcomes. We compared the agreement between detailed information on asthma history and management, collected from the patient and the family physician, to validate the files of physicians and to assess patients' knowledge, attitude, and behavior concerning asthma. A sample of 54 asthma patients were interviewed in detail about use of medications and self-care practice; 36 family physicians (FPs) were interviewed concerning asthma therapy, history, and attitudes of the same patients. Forty-eight percent of the patients expressed negative attitudes toward inhaled corticosteroids, for reasons of safety or lack of efficacy. Less than 20% of the patients made regular use of a peak flow meter. Eighty-three percent of the patients usually obtained prescriptions for asthma therapy from their FP, but on average, only 40% of these prescriptions were provided during visits specific to asthma. FPs were not optimally informed of actual treatments and outcomes and had poor perception of patients' attitudes toward treatment. Nonetheless, in about 30% of the patients, FPs identified risk factors for adverse outcome, such as depression and family conflicts. A majority of interviewed patients had a negative perception of anti-inflammatory therapy, specifically relating to issues of safety and efficacy. Peak flow meters were seldom used and therapy was commonly prescribed outside visits specific to asthma. Despite being centrally involved in the care of asthma patients, FP did not optimally assess therapy and outcomes. The findings suggest suboptimal education and health status in this asthma population.