Self-monitoring of peak flow did not reduce morbidity in asthma
ACP J Club. 1994 July-Aug;121:21. doi:10.7326/ACPJC-1994-121-1-021
Grampian Asthma Study of Integrated Care (GRASSIC). Effectiveness of routine self monitoring of peakflow in patients with asthma. BMJ. 1994 Feb 26;308:564-7.
To evaluate the effectiveness of routine self-monitoring of peak flow in reducing morbidity in outpatients with asthma.
Randomized controlled trial with 1-year follow-up. Part of the Grampian asthma study of integrated care (GRASSIC), designed to evaluate the effectiveness of peak-flow self-monitoring, enhanced education, and integrated care for patients with asthma.
Hospital outpatient clinics and general practices in Scotland.
569 patients (mean age, 51 y; 56% women) who had their diagnosis of asthma confirmed by a specialist and had pulmonary function reversibility of 20% on treatment. Exclusion criteria were age < 16 years or prestudy possession of a peak-flow meter.
285 patients were allocated to self-monitoring of peak flow and 284 were allocated to conventional monitoring of peak flow. Patients in the self-monitoring group were shown how to use a mini-Wright peak-flow meter and received guidelines on when to initiate treatment or seek immediate medical attention. Patients in the conventional-monitoring group were given no self-management advice beyond that normally offered during an outpatient consultation.
Main Outcome Measures
Pulmonary function, number of prescriptions for asthma drugs, number of general practice consultations and hospital admissions for asthma, sleep disturbance and other restrictions on normal activity, and psychological aspects of health.
After 12 months, pulmonary function did not differ between the self-monitoring and conventional-monitoring groups, as assessed by forced expiratory volume in 1 second (74.6% of predicted vs. 75.4%; 95% CI for the -0.8% difference, -5.6% to 4.0%) and peak expiratory flow rate (PEF) (350 vs. 345 L/min; CI for the 5 L/min difference, -17 to 27 L/min). The groups did not differ for use of bronchodilators, oral steroids, and inhaled steroids; the number of general practitioner consultations and hospital admissions; frequency of sleep disturbances and restricted physical activity; and psychological outcomes.
Routine self-monitoring of peak flow did not reduce morbidity in outpatients with asthma.
Sources of funding: Medical Research Council and the Scottish Home and Health Department.
For article reprint: Mr. N. Drummond, Health Services Research Unit, University of Aberdeen, Aberdeen, United Kingdom AB9 2ZD. FAX 44-224-663-087.
Nationwide asthma programs are targeting physicians and the public to increase asthma awareness and improve management. These programs have suggested greater patient monitoring, enhanced education, and integrated care. The GRASSIC series of studies evaluated these options using a factorial design that is appropriate for examining the multiple facets of education and management programs as discrete interventions and also in concert. The design allows the group to answer a question commonly asked of education programs: "What are the important bits?"
It is known that intensive education and management programs improve asthma outcomes and reduce health care costs when they are applied to patients with more severe disease (1). These programs require a high level of intervention and have a high frequency of nonadherence. The GRASSIC study sought to achieve the same results with a less intensive intervention applied to a broad spectrum of patients with asthma. It used many features known to enhance patient compliance; the combination of a patient database and a mail-merge function allowed patients to receive written information about asthma management that was tailored to their circumstances. Personal asthma education is reported to have a better treatment effect than written booklets (1).
The effects of the computer-supported education programs were modest. In agreement with the published literature, hospital admissions were reduced only in those with severe asthma who were the heaviest users of the health care system. A possible explanation is that the level of treatment in the control group had a positive effect. Every 3 months, those in the control group visited their doctor, who reviewed current asthma control and therapy with them and provided self-management advice. This level of care may provide sufficient explanation for the low level of asthma morbidity noted and offset any major effect in the education group.
The computer-based program was well received by the patients. Over two thirds found the information very useful. Although there was little overall effect on morbidity, these positive effects may be sufficient for some to consider the use of this computer-based approach to patient education.
Self-monitoring of asthma allows patients to identify their current level of morbidity from asthma and to detect an asthma exacerbation at an early stage. Previous uncontrolled studies support 2 positive effects of self-monitoring in asthma: a reduction in asthma morbidity and fewer severe exacerbations. The GRASSIC study attempts to identify the effect of self-monitoring of PEF alone and in combination with asthma education. The study found no reduction in morbidity from self-monitoring. This is not surprising because morbidity was probably kept to a minimum by the frequent physician review. The appropriate conclusion is that in the setting of a quarterly physician review of asthma severity and management, the addition of PEF self-monitoring does not further reduce asthma morbidity. It is possible that a positive effect of PEF monitoring on morbidity may exist when less intensive physician review occurs, as was found in a study of persons with asthma who used nonprescription β-agonists (2).
Self-monitoring of PEF did not reduce the number of hospital admissions for asthma, but the study was not large enough to detect a clinically important effect (say, 20% reduction) in the randomized group. In patients with severe asthma, PEF monitoring led to more oral steroid courses, suggesting that it detected more asthma exacerbations in these patients.
Studies that assess the benefits of self-monitoring on the early detection of asthma exacerbation are difficult. Symptom monitoring is often used as the control intervention and may actually be more sensitive than PEF monitoring in the detection of asthma exacerbation (3). If a delay in receiving effective therapy for severe asthma exacerbations is associated with asthma deaths, then self-monitoring seems a reasonable way to promote early detection. Nevertheless, we need precise information on the early markers of asthma exacerbation before further assessment of self-monitoring in asthma.
Peter G. Gibson, MBBS
John Hunter Hospital Newcastle, Australia