Current issues of ACP Journal Club are published in Annals of Internal Medicine


Computer instruction in addition to conventional instruction increased use of measures to avoid allergens and decreased need for medication in asthma

ACP J Club. 1993 Jan-Feb;118:14. doi:10.7326/ACPJC-1993-118-1-014

Source Citation

Huss K, Squire EN Jr, Carpenter GB, et al. Effective education of adults with asthma who are allergic to dust mites. J Allergy Clin Immunol. 1992 Apr;89:836-43.



To study if the addition of a computer program to traditional education for adults with asthma and skin test sensitivity to dust mites will increase measures to avoid house dust mites and decrease mite-allergen burden, asthma symptoms, and medication use.


Randomized controlled trial with 12-week follow-up.


Allergy and immunology clinic of a tertiary care hospital.


Patients had symptomatic asthma, determined by predefined criteria and a positive skin test to Dermatophagoides species. 52 patients (mean age 44 y, 27 women) with mild or moderate asthma were enrolled. Patients with positive skin tests to usual indoor allergens were excluded. Follow-up was 100%.


Patients were randomized to either a conventional education program (individual counseling and printed materials) or to the same program augmented by an interactive self-paced computer program (MS-DOS based). Both programs addressed avoidance measures: encasing mattresses, box springs, and pillows; removing carpeting and upholstered furniture; laundering bedding in hot water; and keeping indoor temperature < 21.1°C (<70°F) and relative humidity < 45%.

Main outcome measures

Site visits were done before and after the study to assess household temperature, humidity, and furnishings and to collect dust samples. Patients recorded medication use at the beginning and end of the study and asthma symptoms twice daily.

Main results

More patients in the computer-instructed group than in the usual-care group implemented avoidance measures (P = 0.023) (Table). The computer-instructed group also had greater decreases in allergen levels on bedroom carpets and floors (P < 0.004) and used less inhaled bronchodilators (4.4 vs 5.2 puffs/d; P = 0.023). The groups did not differ for symptom scores (both groups decreased scores by 26%), household temperature or humidity, mite-allergen levels in mattresses, or mean forced expiratory volume in 1 second (FEV1). Factors associated with adherence were health concerns, support from spouses and friends, physician emphasis, and follow-up.


In adults with mild or moderate asthma the addition of computer-aided instruction to conventional instruction increased adherence with measures to avoid dust-mite-associated allergens and decreased the need for medication.

Sources of funding: In part, Clinical Investigation Service and the Allergy Immunology Service at the Walter Reed Army Medical Center and Spirometrics, Inc.

For article reprint and computer program: Dr. K. Huss, 8616 Aqueduct Road, Potomac, MD 20854, USA. FAX 410-550-2612.

Table. Computer instruction vs usual care at 12 weeks in adults with mild to moderate asthma*

Outcome Computer instruction Usual Care RBI (95% CI) NNT (CI)
Implementation of avoidance measures 81% 46% 75% (15 to 188) 3 ( 2 to 12)

*Abbreviations defined in Glossary; RBI, NNT, and CI calculated from data in article.


Dust mites have been associated with exacerbations of acute asthma and with chronic inflammation of airways. Studies have shown that decreasing allergen levels in patients with positive skin tests reduced airway hyperactivity (1, 2).

Huss and colleagues compared the efficacy of a standard educational intervention with the same intervention plus a computer-assisted instructional program. The study assessed the association of these interventions with the outcome measures of induced behavioral changes, dust mite burden, spirometry, and symptoms. Participants in the experimental group changed their lifestyle more frequently (particularly washing laundry in hot water). They also reduced dust mite allergen levels in their homes. By the end of the study, the groups did not differ in reported symptoms or FEV1. Participants in the experimental group used less inhaled β-agonist, which, although statistically significant, was probably not clinically relevant (a difference of 1 spray/d).

Two methodologic issues cloud the comparison between interventions. Although the trial was randomized, it was not double-blinded. Subjective outcome measures such as reported medication use may have, therefore, favored the experimental group. Also, the 3-fold reduction in allergen levels among the experimental group brought their final values into the same range as the baseline values for the standard intervention group.

The authors achieved greater behavioral change after computer education. In contrast with other studies, however, the study suggests that instructing patients with asthma to undergo potentially costly measures to eliminate dust mites may yield little clinical improvement. Larger trials with longer follow-up are needed to resolve these issues (1).

Roberta B. Ness, MD, MPH
University of PennsylvaniaPhiladelphia, Pennsylvania, USA


1. Walshaw MJ, Evans CC. Allergen avoidance in house dust mite sensitive adult asthma.Q J Med. 1986;58:199-215.

2. Platts-Mills TA, Tovey ER, Mitchell EB, et al. Reduction of bronchial hyperreactivity during prolonged allergen avoidance. Lancet. 1982;2:675-8.