ABSTRACT
Objective To compare the effects of inhaled corticosteroid treatment with leukotriene modifier treatment on medical resource use and costs for asthma patients.
Study design Meta-analysis combining results from published and unpublished studies.
Data sources Studies were identified from the MEDLINE and EMBASE databases and the GlaxoSmithKline internal database study registers. Two independent reviewers evaluated the identified studies; studies meeting specified inclusion criteria were abstracted and summarized by meta-analysis with a random effects model.
Outcomes measured Hospitalization rate, emergency department visit rate, emergency department costs, drug costs, total asthma-related costs, and total medical care costs.
Results Patients taking inhaled corticosteroids had:
a significantly lower annual rate of hospitalization than those taking leukotriene modifiers (2.2% vs 4.3%, respectively;P<.05)
a greater decline in hospitalization rate (before vs after therapy initiation) than those taking leukotriene modifiers (decline of 2.4% vs 0.55%; P<.01)
a lower annual rate of emergency department visits than those taking leukotriene modifiers (6.2% vs 7.7%;P<.005).
lower total asthma-related medical costs than those taking leukotriene modifiers (P<.05) and a 17% reduction in overall total medical care costs (P not significant).
Conclusions Patients with asthma treated with inhaled corticosteroids had significantly fewer asthma-related hospitalizations and emergency department visits and lower total asthma-related health care costs than patients treated with leukotriene modifiers. These meta-analysis findings are consistent with results from randomized controlled trials showing improvements in lung function for patients taking inhaled corticosteroids as opposed to leukotriene modifiers.
Although many medications are available for patients with asthma, inhaled corticosteroids are generally the preferred treatment.1-4 Multiple studies have demonstrated that inhaled corticosteroid therapy improves patient outcomes.1 Inhaled corticosteroids have been shown to decrease costs5 and use of medical care resources.6-8
More recently, leukotriene modifiers have been introduced for asthma treatment. This class of medication has bronchodilator and anti-inflammatory effects.9 Although multiple studies have indicated improved outcomes and decreased costs associated with leukotriene modifier therapy incertain patient populations,10,11 its role in asthmamanagement is uncertain.9
Several studies have compared the clinical outcomes of these therapies12-15 and their impact on medical care resource use and costs.16,17 However, these studies were not powered specifically to detect significant differences in resource use or costs.
We performed a meta-analysis to (1) compare the rate of hospitalization among patients with asthma treated with inhaled corticosteroids vs those treated with leukotriene modifiers and (2) evaluate other resource use rates and costs for these patients.
Methods
The meta-analysis consisted of a literature search, the development of inclusion criteria, form development, and literature review.
Literature search
We searched the MEDLINE, EMBASE, Cochrane Collaboration Study Registry, and GlaxoSmithKline databases and consulted experts in this field. The GlaxoSmithKline database consists of studies sponsored by GlaxoSmithKline that met companywide minimum quality thresholds and were published in full or abstract form.
We also contacted the manufacturers of leukotriene modifiers available in the United States, AstraZeneca and Merck, to request published and unpublished information on studies comparing leukotriene modifiers with inhaled corticosteroids. To provide results corresponding to current treatment patterns, only studies from 1991 to 2001 were included. Published and unpublished materials were included.18,19
Inclusion criteria
Studies were included in the meta-analysis if they met the following criteria.
Population. Patients with diagnosed asthma. Only studies that did not restrict analyses to severe asthma patients or children were included.
Study design. Prospective and retrospective comparative studies of patients receiving inhaled corticosteroid or leukotriene modifier monotherapy (no other controller therapy) in the same study. Studies were required to have defined inclusion and exclusion criteria, defined number of patients in each study arm, defined treatment protocol (ie, medications and doses used), and separate results for each medication.
Only studies presenting primary research (hence excluding review articles and metaanalyses) were included. Only studies presenting data for at least 6 months on all participants were included.
Outcomes. Hospitalization visit rates and costs, emergency department visit rates and costs, pharmacy costs, total asthma-related costs, and total medical care costs. Because resource use patterns and medical care cost information differs substantially between countries, we only included US studies.
Study process
Each identified article was evaluated by 2 independent reviewers (KMS and MG); any differences were discussed with a project leader to reach a consensus. Documents selected for inclusion were then reviewed by the 2 reviewers, and differences in data abstraction were resolved before inclusion.
Analysis
We used the Q statistic20 to assess heterogeneity and, when appropriate, combined data from included studies with the use of a random effects model. Random effects methodology was used to assess the impact of inhaled corticosteroid vs leukotriene modifier therapy on the overall asthma population, not just the subpopulation of patients participating in included studies.21