Randomised aspirin assignment and risk of adult-onset asthma in the Women's Health Study

Predicting Asthma Exacerbations Using Machine Learning Models

INTRODUCTION

Although clinical, functional, and biomarker data predict asthma exacerbations, newer approaches providing high accuracy of prognosis are needed for real-world decision-making in asthma. Machine learning (ML) leverages mathematical and statistical methods to detect patterns for future disease events across large datasets from electronic health records (EHR). This study conducted training and fine-tuning of ML algorithms for the real-world prediction of asthma exacerbations in patients with physician-diagnosed asthma.

METHODS

Adults with ≥ 2 ICD9/10 asthma codes within 1 year and at least 30 days apart were identified from the Optum Panther EHR database between 2016 and 2023. An emergency department (ED), urgent care, or inpatient visit for asthma, while on systemic administration of corticosteroids, was considered an exacerbation. To predict factors associated with exacerbations in a 6-month study period, clinical information from patients was retrieved in the preceding 6-month baseline period. Clinical information included demographics, lab results, diagnoses, medications, immunizations, and allergies. Three models built using Extreme Gradient Boosting (XGBoost), Long Short-Term Memory (LSTM), and Transformers algorithms were trained and tested on independent datasets. Predictions were explained using the SHAP (SHapley Additive exPlanations) library.

RESULTS

Of 1,331,934 patients with asthma, 16,279 (1.2%) experienced ≥ 1 exacerbation. XGBoost was the best predictive algorithm (area under the curve [AUC] = 0.964). Factors associated with exacerbations included a prior history of exacerbation, prednisone usage, high-dose albuterol usage, and elevated troponin I. Reduced probability of exacerbations was associated with receiving inhaled albuterol, vitamins, aspirin, statins, furosemide, and influenza vaccination.

CONCLUSION

This ML-based study on asthma in the real world confirmed previously known features associated with increased exacerbation risk for asthma, while uncovering not entirely understood features associated with reduced risk of asthma exacerbations. These findings are hypothesis-generating and should contribute to ongoing discussion of the strengths and limitations of ML and other supervised learning models in patient risk stratification.

Exposure to Proton Pump Inhibitors and the Risk of Incident Asthma in Patients with Coronary Artery Diseases: A Population-Based Cohort Study

We aimed to determine the association between proton pump inhibitor (PPI) use and incident asthma in patients with coronary artery disease (CAD). This nationwide cohort study collected claims data from the Taiwanese Bureau of National Health Insurance from 2004 to 2013. The primary outcome, i.e., the risk of incident asthma, was assessed by estimating hazard ratios (HRs) and 95% confidence intervals (CIs). The adjusted HR of asthma development was estimated using the Cox regression model. Sensitivity and subgroup analyses were also conducted. A total of 8894 PPI users and 12,684 H2-receptor antagonist (H2RA) users were included in patients with CAD. Compared with H2RA use, an increased risk of incident asthma was found between PPI use and the risk of incident asthma in patients with CAD after adjusting for sex, age, urbanization, and low income (HR: 1.41; 95% CI: 1.04-1.89). The sensitivity analysis results were consistent with the main analysis results. However, the subgroup analysis revealed no association of incident asthma in patients with diabetes mellitus, hyperlipidemia, stroke, allergic rhinitis, pneumonia, cancer, or depression in the PPI group compared with those in the H2RA group. In conclusion, PPI use increased the risk of asthma development in patients with CAD.

Emerging Roles of Platelets in Allergic Asthma

Allergic asthma is a complex chronic inflammatory disease of the airways, driven by Th2 immune responses and characterized by eosinophilic pulmonary inflammation, airway hyperresponsiveness, excessive mucus production, and airway remodeling. Overwhelming evidence from studies in animal models and allergic asthmatic patients suggests that platelets are aberrantly activated and recruited to the lungs. It has been established that platelets can interact with other immune cells and secrete various biochemical mediators to promote allergic sensitization and airway inflammatory response, and platelet deficiency may alleviate the pathological features and symptoms of allergic asthma. However, the comprehensive roles of platelets in allergic asthma have not been fully clarified, leaving attempts to treat allergic asthma with antiplatelet agents questionable. In this review, we summarize the role of platelet activation and pulmonary accumulation in allergic asthma; emphasis is placed on the different interactions between platelets with crucial immune cell types and the contribution of platelet-derived mediators in this context. Furthermore, clinical antiplatelet approaches to treat allergic asthma are discussed. This review provides a clearer understanding of the roles of platelets in the pathogenesis of allergic asthma and could be informative in the development of novel strategies for the treatment of allergic asthma.

The association between paracetamol use and asthma: causation or coincidence?

A better understanding of the causation of asthma and allergic disorders could potentially lead to intervention strategies that reduce their prevalence and severity. One potential causative factor is the use of paracetamol. Most of the evidence for the link with asthma is from non-experimental studies of paracetamol exposure in utero, infancy, childhood and adult life; however, it has been difficult to rule out confounding and bias in the associations observed. The two randomized clinical trials of the effect of paracetamol in patients with asthma have been difficult to interpret, due to methodological issues. There have been no randomized controlled trials of paracetamol use and the development of asthma. Both asthma and paracetamol use are common, and so even if there is a relatively small effect of paracetamol exposure on the development of asthma or its severity, then such an effect would be of major public health significance. It is proposed that randomized controlled trials of the effect of paracetamol on the development of asthma and its severity are a high research priority.

Vitamins C and E for asthma and exercise-induced bronchoconstriction

BACKGROUND

The association between dietary antioxidants and asthma or exercise-induced bronchoconstriction (EIB) is not fully understood. Vitamin C and vitamin E are natural antioxidants that are predominantly present in fruits and vegetables; inadequate vitamin E intake is associated with airway inflammation. It has been postulated that the combination may be more beneficial than either single antioxidant for people with asthma and exercise-induced bronchoconstriction.

OBJECTIVES

To assess the effects of supplementation of vitamins C and E versus placebo (or no vitamin C and E supplementation) on exacerbations and health-related quality of life (HRQL) in adults and children with chronic asthma. To also examine the potential effects of vitamins C and E on exercise-induced bronchoconstriction in people with asthma and in people without a diagnosis of asthma who experience symptoms only on exercise.

SEARCH METHODS

Trials were identified from the Cochrane Airways Review Group Specialised Register and from trial registry websites. Searches were conducted in September 2013.

SELECTION CRITERIA

We included randomised controlled trials of adults and children with a diagnosis of asthma. We separately considered trials in which participants had received a diagnosis of exercise-induced bronchoconstriction (or exercise-induced asthma). Trials comparing vitamin C and E supplementation versus placebo were included. We included trials in which asthma management for treatment and control groups included similar background therapy. Short-term use of vitamins C and E at the time of exacerbation or for cold symptoms in people with asthma is outside the scope of this review.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the titles and abstracts of potential studies and subsequently screened full-text study reports for inclusion. We used standard methods as expected by The Cochrane Collaboration.

MAIN RESULTS

It was not possible to aggregate the five included studies (214 participants). Four studies (206 participants) addressed the question of whether differences in outcomes were seen when vitamin C and E supplementation versus placebo was provided for participants with asthma, and only one of those studies (160 children) included a paediatric population; the remaining three studies included a combined total of just 46 adults. An additional study considered the question of whether differences in outcomes were noted when vitamin C and E supplementation was compared with placebo for exercise-induced asthma; this trial included only eight participants. The randomisation process of the trials were unclear leading us to downgrade the quality of the evidence. Four of the studies were double blind while the other study was single blind.None of these studies provided data on our two prespecified primary outcome measures: exacerbations and HRQL. Lung function data obtained from the studies were inconclusive. The only studies that provided any suggestion of an effect, and only with some outcomes, were the paediatric study, especially for children with moderate to severe asthma, and the small study on exercise-induced asthma. Even so, this evidence was judged to be at moderate/low quality. Only one study contributed data on asthma symptoms and adverse events, reporting no evidence of an effect of the intervention for symptoms and that one participant in the treatment group dropped out due to cystitis.

AUTHORS' CONCLUSIONS

It is not possible to draw firm conclusions from this review with respect to the comparison of vitamin C and E supplementation versus placebo in the management of asthma or exercise-induced bronchoconstriction. We found only one study relevant to exercise-induced bronchoconstriction; most included participants came from studies designed to assess the effect of vitamin supplementation on the impact of atmospheric pollutants (such as ozone). Evidence is lacking on the comparison of vitamin C and E supplementation versus placebo for asthma with respect to outcomes such as HRQL and exacerbations, which were not addressed by any of the included studies.When compared with lung function tests alone, HRQL scores and exacerbation frequency are better indicators of the severity of asthma, its impact on daily activities and its response to treatment in a patient population. These end points are well recognised in good quality studies of asthma management. However, clinical studies of vitamins C and E in the management of asthma using these important end points of exacerbations and effects on quality of life are not available, and evidence is insufficient to support robust conclusions on the role of vitamin C and E supplementation in asthma and exercise-induced breathlessness.

Vitamin C for asthma and exercise-induced bronchoconstriction

BACKGROUND

Dietary antioxidants, such as vitamin C, in the epithelial lining and lining fluids of the lung may be beneficial in the reduction of oxidative damage (Arab 2002). They may therefore be of benefit in reducing symptoms of inflammatory airway conditions such as asthma, and may also be beneficial in reducing exercise-induced bronchoconstriction, which is a well-recognised feature of asthma and is considered a marker of airways inflammation. However, the association between dietary antioxidants and asthma severity or exercise-induced bronchoconstriction is not fully understood.

OBJECTIVES

To examine the effects of vitamin C supplementation on exacerbations and health-related quality of life (HRQL) in adults and children with asthma or exercise-induced bronchoconstriction compared to placebo or no vitamin C.

SEARCH METHODS

We identified trials from the Cochrane Airways Group's Specialised Register (CAGR). The Register contains trial reports identified through systematic searches of a number of bibliographic databases, and handsearching of journals and meeting abstracts. We also searched trial registry websites. The searches were conducted in December 2012.

SELECTION CRITERIA

We included randomised controlled trials (RCTs). We included both adults and children with a diagnosis of asthma. In separate analyses we considered trials with a diagnosis of exercise-induced bronchoconstriction (or exercise-induced asthma). We included trials comparing vitamin C supplementation with placebo, or vitamin C supplementation with no supplementation. We included trials where the asthma management of both treatment and control groups provided similar background therapy. The primary focus of the review is on daily vitamin C supplementation to prevent exacerbations and improve HRQL. The short-term use of vitamin C at the time of exacerbations or for cold symptoms in people with asthma are outside the scope of this review.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the titles and abstracts of potential studies, and subsequently screened full text study reports for inclusion. We used standard methods expected by The Cochrane Collaboration.

MAIN RESULTS

A total of 11 trials with 419 participants met our inclusion criteria. In 10 studies the participants were adults and only one was in children. Reporting of study design was inadequate to determine risk of bias for most of the studies and poor availability of data for our key outcomes may indicate some selective outcome reporting. Four studies were parallel-group and the remainder were cross-over studies. Eight studies included people with asthma and three studies included 40 participants with exercise-induced asthma. Five studies reported results using single-dose regimes prior to bronchial challenges or exercise tests. There was marked heterogeneity in vitamin C dosage regimes used in the selected studies, compounding the difficulties in carrying out meaningful analyses.One study on 201 adults with asthma reported no significant difference in our primary outcome, health-related quality of life (HRQL), and overall the quality of this evidence was low. There were no data available to evaluate the effects of vitamin C supplementation on our other primary outcome, exacerbations in adults. One small study reported data on asthma exacerbations in children and there were no exacerbations in either the vitamin C or placebo groups (very low quality evidence). In another study conducted in 41 adults, exacerbations were not defined according to our criteria and the data were not available in a format suitable for evaluation by our methods. Lung function and symptoms data were contributed by single studies. We rated the quality of this evidence as moderate, but further research is required to assess any clinical implications that may be related to the changes in these parameters. In each of these outcomes there was no significant difference between vitamin C and placebo. No adverse events at all were reported; again this is very low quality evidence.Studies in exercise-induced bronchoconstriction suggested some improvement in lung function measures with vitamin C supplementation, but theses studies were few and very small, with limited data and we judged the quality of the evidence to be low.

AUTHORS' CONCLUSIONS

Currently, evidence is not available to provide a robust assessment on the use of vitamin C in the management of asthma or exercise-induced bronchoconstriction. Further research is very likely to have an important impact on our confidence in the estimates of effect and is likely to change the estimates. There is no indication currently that vitamin C can be recommended as a therapeutic agent in asthma. There was some indication that vitamin C was helpful in exercise-induced breathlessness in terms of lung function and symptoms; however, as these findings were provided only by small studies they are inconclusive. Most published studies to date are too small and inconsistent to provide guidance. Well-designed trials with good quality clinical endpoints, such as exacerbation rates and health-related quality of life scores, are required.

Acetaminophen and asthma

Acetaminophen is a widely used medication for the treatment of pain and fever in children and pregnant women. There is substantial epidemiological evidence in adults and children that acetaminophen use is associated with asthma symptoms. There is also a considerable body of evidence that supports a modest but consistent association of acetaminophen use in pregnancy and early infancy with asthma in later childhood. This relationship is robust to adjustment for a large range of potential confounding factors and, in some studies, shows clear evidence of a dose-dependent association but the possibility of confounding by indication has remained a concern. However, the epidemiological evidence is now compelling and there is a clear need to establish causation so that appropriate advice and interventions can be developed for children at risk of asthma. This requires randomised trials of analgesics and antipyretics, including acetaminophen, in a variety of clinical settings.

Adult-onset asthma: is it really different?

Asthma that starts in adulthood differs from childhood-onset asthma in that it is often non-atopic, more severe and associated with a faster decline in lung function. Understanding of the underlying mechanism of adult-onset asthma and identification of specific phenotypes may further our understanding of pathophysiology and treatment response, leading to better targeting of both existing and new approaches for personalised management. Pivotal studies in past years have led to sustained progress in many areas, ranging from risk factors for development, identification of different phenotypes, and introduction of new therapies. This review highlights and discusses literature on adult-onset asthma, with special focus on the differences from childhood-onset asthma, risk factors for development, phenotypes of adult-onset asthma and new approaches for personalised management.

Effects of Acetaminophen consumption in asthmatic children

BACKGROUND

Acetaminophen exposure might be associated with increasing risk of asthma prevalence and other atopic disorders over recent decades. The present study aimed to investigate the association between acetaminophen exposure and the risk of developing childhood asthma.

METHODS

A case - control study was undertaken between March and September 2010 in Urmia district north west of Iran. Subjects were children aged between 2 - 8 years old. Cases were asthmatic children diagnosed based on GINA criteria (n=207) and controls were children without asthma symptoms (n=414) using 1:2 sampling method. Cases and controls were matched for age and gender. Clinical data including Acetaminophen exposure was collected by a questionnaire which completed by interviewing with parents/ guardians.

RESULTS

Using Acetaminophen during the first year of life had no any effect on the risk of asthma (p=0.19), but amongst 2-8 years old children, this association was observed (p<0.001). There was also a doseresponseassociation between Acetaminophen consumption and risk of asthma (OR: 3.8; 95% CI; 2.15 6.59 for once per 2 to 3 month and OR: 4.2; 2.50 - 7.3 for at least one per month).

CONCLUSIONS

Using Acetaminophen increases risk of asthma among 2 - 8 years old children. However stronger evidences are required to design evidence-based guidelines to reduce acetaminophen consumption following post - vaccination and other febrile disorders.

Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases

BACKGROUND

Our systematic review has demonstrated that antioxidant supplements may increase mortality. We have now updated this review.

OBJECTIVES

To assess the beneficial and harmful effects of antioxidant supplements for prevention of mortality in adults.

SEARCH METHODS

We searched The Cochrane Library, MEDLINE, EMBASE, LILACS, the Science Citation Index Expanded, and Conference Proceedings Citation Index-Science to February 2011. We scanned bibliographies of relevant publications and asked pharmaceutical companies for additional trials.

SELECTION CRITERIA

We included all primary and secondary prevention randomised clinical trials on antioxidant supplements (beta-carotene, vitamin A, vitamin C, vitamin E, and selenium) versus placebo or no intervention.

DATA COLLECTION AND ANALYSIS

Three authors extracted data. Random-effects and fixed-effect model meta-analyses were conducted. Risk of bias was considered in order to minimise the risk of systematic errors. Trial sequential analyses were conducted to minimise the risk of random errors. Random-effects model meta-regression analyses were performed to assess sources of intertrial heterogeneity.

MAIN RESULTS

Seventy-eight randomised trials with 296,707 participants were included. Fifty-six trials including 244,056 participants had low risk of bias. Twenty-six trials included 215,900 healthy participants. Fifty-two trials included 80,807 participants with various diseases in a stable phase. The mean age was 63 years (range 18 to 103 years). The mean proportion of women was 46%. Of the 78 trials, 46 used the parallel-group design, 30 the factorial design, and 2 the cross-over design. All antioxidants were administered orally, either alone or in combination with vitamins, minerals, or other interventions. The duration of supplementation varied from 28 days to 12 years (mean duration 3 years; median duration 2 years). Overall, the antioxidant supplements had no significant effect on mortality in a random-effects model meta-analysis (21,484 dead/183,749 (11.7%) versus 11,479 dead/112,958 (10.2%); 78 trials, relative risk (RR) 1.02, 95% confidence interval (CI) 0.98 to 1.05) but significantly increased mortality in a fixed-effect model (RR 1.03, 95% CI 1.01 to 1.05). Heterogeneity was low with an I(2)- of 12%. In meta-regression analysis, the risk of bias and type of antioxidant supplement were the only significant predictors of intertrial heterogeneity. Meta-regression analysis did not find a significant difference in the estimated intervention effect in the primary prevention and the secondary prevention trials. In the 56 trials with a low risk of bias, the antioxidant supplements significantly increased mortality (18,833 dead/146,320 (12.9%) versus 10,320 dead/97,736 (10.6%); RR 1.04, 95% CI 1.01 to 1.07). This effect was confirmed by trial sequential analysis. Excluding factorial trials with potential confounding showed that 38 trials with low risk of bias demonstrated a significant increase in mortality (2822 dead/26,903 (10.5%) versus 2473 dead/26,052 (9.5%); RR 1.10, 95% CI 1.05 to 1.15). In trials with low risk of bias, beta-carotene (13,202 dead/96,003 (13.8%) versus 8556 dead/77,003 (11.1%); 26 trials, RR 1.05, 95% CI 1.01 to 1.09) and vitamin E (11,689 dead/97,523 (12.0%) versus 7561 dead/73,721 (10.3%); 46 trials, RR 1.03, 95% CI 1.00 to 1.05) significantly increased mortality, whereas vitamin A (3444 dead/24,596 (14.0%) versus 2249 dead/16,548 (13.6%); 12 trials, RR 1.07, 95% CI 0.97 to 1.18), vitamin C (3637 dead/36,659 (9.9%) versus 2717 dead/29,283 (9.3%); 29 trials, RR 1.02, 95% CI 0.98 to 1.07), and selenium (2670 dead/39,779 (6.7%) versus 1468 dead/22,961 (6.4%); 17 trials, RR 0.97, 95% CI 0.91 to 1.03) did not significantly affect mortality. In univariate meta-regression analysis, the dose of vitamin A was significantly associated with increased mortality (RR 1.0006, 95% CI 1.0002 to 1.001, P = 0.002).

AUTHORS' CONCLUSIONS

We found no evidence to support antioxidant supplements for primary or secondary prevention. Beta-carotene and vitamin E seem to increase mortality, and so may higher doses of vitamin A. Antioxidant supplements need to be considered as medicinal products and should undergo sufficient evaluation before marketing.

The role of paracetamol in the pathogenesis of asthma

Paracetamol use represents a putative risk factor for the development of asthma. There is convincing epidemiological evidence that the risk of asthma may be increased with exposure to paracetamol in the intrauterine environment, infancy, later childhood and adult life. A dose-dependent association has also been observed in these different age groups in different populations world-wide. An association has also been shown between paracetamol use in both rhinoconjunctivitis and eczema. There is biological plausibility with paracetamol use leading to decreased glutathione levels resulting in increased oxidant-induced inflammation and potentially enhanced T-helper type 2 responses. At the population level, patterns of paracetamol use might explain, to some extent, the world-wide variation in the prevalence of asthma and related disorders, particularly the high rates in English-speaking countries, which have high per capita prescription and over-the-counter use of paracetamol. A temporal association also exists between the international trends of increasing paracetamol use and increasing prevalence of asthma over recent decades. Further research is urgently required, in particular randomized-controlled trials (RCTs) into the long-term effects of frequent paracetamol use in childhood, to determine the magnitude and characteristics of any such risk. Importantly, RCTs will also enable evidence-based guidelines for the recommended use of paracetamol to be developed.

Low-dose aspirin in the primary prevention of rheumatoid arthritis: the Women's Health Study

OBJECTIVE

Low-dose aspirin may reduce the risk of developing rheumatoid arthritis (RA) through its effect on cyclooxygenase activity and its antioxidant pathways. Previous randomized trial data have demonstrated a beneficial effect of low-dose aspirin in reducing other inflammatory diseases, such as asthma and colorectal adenomas, but no trial has evaluated the role of aspirin in RA prevention.

METHODS

The Women's Health Study is a randomized, double-blind, placebo-controlled trial conducted between 1992 and 2004 designed to evaluate the risks and benefits of low-dose aspirin (100 mg every other day) and vitamin E in the primary prevention of cardiovascular disease and cancer among 39,876 female health care professionals age > or =45 years throughout the US. After excluding women with RA at baseline, 39,144 women were evaluated for the present study. A definite diagnosis of RA was assessed during followup by self-report and confirmed using a connective tissue disease screening questionnaire, followed by a medical record review by a rheumatologist for American College of Rheumatology criteria.

RESULTS

During an average followup of 10 years, 106 women developed definite RA (48 women in the aspirin group and 58 in the placebo group). There was a nonsignificant risk for RA (relative risk [RR] 0.83, 95% confidence interval [95% CI] 0.56-1.21; P = 0.33) associated with aspirin. There were 64 seropositive RA cases (60%) and 42 seronegative RA cases (40%). Aspirin also had no significant effect on either seropositive RA (RR 1.0, 95% CI 0.61-1.63) or seronegative RA (RR 0.62, 95% CI 0.33-1.15).

CONCLUSION

One hundred milligrams of aspirin taken every other day was not associated with a significant reduction in the risk of developing RA among women in a randomized, double-blind, placebo-controlled trial.

Modulation by aspirin of nuclear phospho-signal transducer and activator of transcription 6 expression: Possible role in therapeutic benefit associated with aspirin desensitization

BACKGROUND

Aspirin-exacerbated respiratory disease is characterized by asthma, nasal polyps, and intolerance to aspirin with overexpression of leukotriene (LT) C(4) synthase and cysteinyl leukotriene receptors. Through an unknown mechanism, aspirin desensitization is an effective treatment.

OBJECTIVE

We hypothesized that aspirin desensitization blocks IL-4-induced expression of these LT activities through inhibition of signal transducer and activator of transcription 6 (STAT6)-mediated transcription.

METHODS

Nuclear extracts were derived from THP-1 and normal human monocytes resting and cocultured with aspirin before IL-4 stimulation. Quantitative PCRs were conducted. Electrophoretic mobility shift assays were performed by using oligomers for STAT6 sites within the LT receptor and synthase promoters. Western blots of nuclear extracts were probed by using anti-phospho-STAT6 antibodies.

RESULTS

Upregulation of LT receptor mRNA by IL-4 was negated by aspirin and ketorolac but not by sodium salicylate. The STAT6 site in the LT receptor and synthase promoters was confirmed by using mobility shift assays by competing with unlabeled STAT6 consensus probes and supershifts with anti-STAT6 antibodies. Aspirin and ketorolac decreased the IL-4-inducible expression of nuclear STAT6 observed in mobility shift assays and Western hybridization.

CONCLUSION

The LT receptor and synthase promoters have STAT6-binding sites that are engaged by IL-4-induced nuclear extracts and inhibited by aspirin. Assuming that normal monocytes behave like monocytes from patients with aspirin-exacerbated respiratory disease, inhibition of IL-4-STAT6 might explain a mechanism in aspirin desensitization daily treatment, resulting in downregulation of production and responsiveness to cysteinyl leukotrienes. This biologic activity of aspirin likely reflects COX inhibition because it was shared with ketorolac but not sodium salicylate.

Efficacy of sulphasalazine on lung histopathology in a murine model of chronic asthma

Sulphasalazine is a specific inhibitor of nuclear factor kappa B (NF-kappa B) which plays a key role in asthma. To determine the impact of sulphasalazine in the treatment of chronic asthma, BALB/c mice were sensitized and challenged with ovalbumin. Mice with experimentally induced asthma in group I received saline, group II sulphasalazine 200 mg/kg, group III sulphasalazine 300 mg/kg, and group IV dexamethasone 1 mg/kg intraperitoneally once a day in the last 7 days of the challenge period. Histological findings of the airways were evaluated by light and electron microscopies. Dexamethasone and sulphasalazine in both doses significantly improved all airway histopathologic parameters of asthma except numbers of goblet cells. Both doses of sulphasalazine improved thicknesses of basement membrane better than dexamethasone. Dexamethasone reduced the number of mast cells better than sulphasalazine (200 mg/kg). Further studies are needed to evaluate the efficacy of sulphasalazine in the treatment of asthma.