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R Beasley

Publications and source records attributed to R Beasley.

At least 73 records · Page 4Linked to original sources
PubMed1998

Classification of asthma severity: should the international guidelines be changed?

BACKGROUND: International guidelines recommend that, in addition to symptoms and medication requirements, measurements of forced expiratory volume in one second (FEV1) and peak expiratory flow (PEF) are necessary for the objective assessment of asthma severity. The guidelines suggest that parity exists between measurements of FEV1 and PEF when expressed as percentage of predicted normal values, and that asthma severity can be classified as mild, moderate or severe on the basis of FEV and PEF measurements of > 80%, 60-80% and < 60% of predicted values, respectively. OBJECTIVE: To determine the relationship between measurements of FEV1 and PEF when expressed as percentage predicted values. METHODS: A total of 1198 paired measurements of FEV1 and PEF were obtained from the medical records of a random sample of 25 adult asthmatic patients attending a hospital-based chest clinic. Measurements of lung function were expressed as a percentage of predicted normal values, using the European Respiratory Society prediction equations for PEF and FEV1. For the individual paired measurements, the mean differences between PEF and FEV percentage predicted were calculated. Measurements of lung function were used to determine asthma severity with <60%, 60-80%, and >80% predicted FEV1 and PEF values representing severe, moderate and mild asthma, respectively. The proportion of paired measurements in which differences in classification resulted from the use of FEV1 or PEF percentage predicted values was then calculated. RESULTS: In asthma of differing severity, there was considerable variability between measurements of FEV1 and PEF when expressed as percentage predicted values; calculation of the FEV1% predicted resulted in lower values than those of the PEF percentage predicted, with a mean difference of -17.2% (95% CI -16.3%, -18.1%). There was agreement in classification of asthma severity in only 49.9% (598/1198) of paired measurements. Different prediction equations, while variably altering the degree of misclassification, did not correct the basic differences in the assessment of asthma severity dependent on the use of FEV or PEF. CONCLUSION: FEV1 and PEF values, expressed as percentage predicted, are not equivalent. Pending further evaluation, the authors suggest that published asthma guidelines should avoid the assumption of parity between these two measurements.

Adolescent↗
PubMed1998

Case-control study of salmeterol and near-fatal attacks of asthma.

BACKGROUND: A case-control study was undertaken to investigate the hypothesis that the use of the long acting beta agonist salmeterol increases the risk of a near-fatal attack of asthma. METHODS: The cases comprised admissions to the intensive care unit (ICU) for asthma in 14 major hospitals within the Wessex region in 1992. For each of the cases four age-matched controls were selected from asthma admissions to the same hospital during the same period. Information on prescribed drug therapy for the 48 cases and 185 controls was collected from the hospital admission records. RESULTS: The patients admitted to the ICU had greater chronic asthma severity and had generally been prescribed more asthma drugs than the control admissions to hospital. The relative risk of a near-fatal attack of asthma in patients prescribed inhaled salmeterol was 2.32 (95% CI 1.05 to 5.16), p = 0.04. However, the salmeterol relative risk decreased to 1.42 (95% CI 0.49 to 4.10), p = 0.52 when the analysis was restricted to the more chronically severe patients (those in the subgroup of patients with a hospital admission for asthma in the previous 12 months). These findings suggest that the increased unadjusted relative risk with salmeterol is predominantly due to confounding by severity--that is, the increased relative risk is due to patients with more severe asthma (at greatest risk of a near-fatal asthma attack) being preferentially prescribed salmeterol. This interpretation is supported by the finding in this study that, within the control group (selected from the population of asthmatics requiring hospital admission), salmeterol was preferentially prescribed to the most severe patients (a threefold greater prescription of salmeterol to control patients if they had been admitted to hospital in the 12 months prior to the index admission). There was no increased risk of a near-fatal attack of asthma in patients prescribed a beta agonist by metered dose inhaler (OR 0.75 (95% CI 0.31 to 1.78), p = 0.51). In contrast, the relative risks for beta agonists delivered by nebulisation (OR 3.86 (95% CI 1.99 to 7.50), p < 0.001) and oral theophylline (OR 2.45 (95% CI 1.26 to 4.78), p < 0.01) were increased and did not markedly decrease when the analysis was restricted to the more severe asthmatic subjects. CONCLUSIONS: Although these findings are not conclusive, particularly because of the small numbers involved in some subgroup analyses, they suggest that the use of salmeterol by patients with chronic severe asthma is not associated with a significantly increased risk of a near-fatal attack of asthma. If a near-fatal asthma attack is considered to be an intermediate step in a process by which a severe attack of asthma may become fatal, these results would suggest that salmeterol is unlikely to be associated with an increased risk of death, at least by this mechanism.

Adolescent↗
PubMed1998

Long-term reduction in asthma morbidity following an asthma self-management programme.

The adult "credit card" asthma self-management plan has been shown to be an effective and acceptable system for reducing asthma morbidity when introduced as part of a 6 month community-based asthma programme. The aim of the present study was to assess the effectiveness of the credit card plan 2 yrs after the end of the programme. Markers of asthma morbidity and use of medical services were compared during the 12 months before enrolment, and 2 yrs after completing the 6 month asthma programme. Of the 69 participants who originally enroled in the 6 month asthma programme, 58 were surveyed 2 yrs after completion of the programme. These participants showed a significant improvement in all but one of the asthma morbidity measures. The proportion waking most nights with asthma in the previous 12 months decreased from 29 to 9% (p=0.02), emergency visits to a general practitioner decreased from 43 to 16% (p=0.001), hospital emergency department visits with asthma decreased from 19 to 5% (p=0.02) and hospital admissions decreased from 17 to 5% (p=0.04). Only 24% of patients reported that they usually monitored their peak flow rate daily, but this increased to 73% during a "bad" attack of asthma. A long-term reduction in asthma morbidity and requirement for acute medical services can result following the introduction of the adult credit card asthma self-management plan. Adult patients with asthma are most likely to undertake peak flow monitoring preferentially during periods of unstable asthma, rather than routinely during periods of good control.

Adult↗
PubMed1997

Geographical variation in the prevalence of asthma symptoms in New Zealand.

AIMS: To examine geographical variations in the prevalence of asthma symptoms in a random population sample of New Zealand adults aged 20-44 years. METHODS: A one page asthma symptom questionnaire was sent to 31470 people aged 20-44 years. The questionnaire asked about respiratory symptoms, asthma attacks and asthma treatment. Those who had not responded after two reminder postcards were followed with a telephone call where possible. RESULTS: A response rate of 82% (25664) was achieved. The 12 month period prevalence of asthma (defined as woken by shortness of breath, or an attack of asthma in the past year, or current asthma medication) was 15.2% overall, but was higher in females (17.0%) than in males (13.2%); the prevalence was 22.1% in Maori, 20.6% in Pacific Islanders and 14.3% in non Polynesians. In North Island electorates, the highest age and ethinicity standardised prevalences were found in some of the electorates in the Auckland and Wellington urban regions although prevalence was also high in some rural electorates including Raglan (18.0%), Horowhenua (18.4%) and Wairarapa (18.4%); the lowest prevalences were found in other rural electorates including King Country (5.5%), Matamata (10.1%) and Rotorua (10.3%). In South Island electorates, the highest prevalences were found in some electorates in the Christchurch and Dunedin urban areas, and the lowest prevalences were again found in rural electorates including Clutha (11.3%), Rangiora (9.5%) and Wallace (9.4%). CONCLUSIONS: This study confirms the previously reported high frequency of asthma symptoms in New Zealand adults, with higher symptom prevalence in Maori and in women. It shows significant urban/rural differences, as well as marked differences in prevalence between various rural areas. The reasons for these patterns are unclear and require further study.

Adult↗
PubMed1997

International trends in asthma mortality.

Throughout the 20th century many different patterns of asthma mortality have been observed. Following relatively stable asthma mortality rates during the first half of this century, there has been a gradual increase in asthma mortality in many countries over the last 50 years. Although a number of possible explanations have been proposed to explain this trend-including increases in asthma prevalence, increases in exposure to factors that trigger asthma attacks and changes in asthma management-their relative contribution in different countries is uncertain. Another pattern is that of sudden marked increases in asthma mortality occurring in at least seven countries in the 1960s and in New Zealand in the 1970s. Available evidence indicates that the cause of these 'epidemics' was the use of high dose preparations of two specific beta-agonist drugs, namely isoprenaline forte and fenoterol. The most recent trend observed in a number of western countries during the last decade has been a gradual reduction in asthma mortality; this may relate to improvements in the management of asthma.

Asthma↗
PubMed1997

Perinatal factors and atopic disease in childhood.

BACKGROUND: Recent work has suggested possible linkages between perinatal factors and notably, head circumference and risks of subsequent atopic illness. OBJECTIVE: To examine the linkages between perinatal factors and risks of atopic conditions in a birth cohort of New Zealand children studied to the age of 16. METHODS: Measures of atopic illness including asthma, eczema, and other allergies were assessed prospectively during the course of a 16 year longitudinal study of a birth cohort of 1265 New Zealand children. In the initial stage of this research, measures of perinatal variables including birthweight, gestational age, head circumference and length at birth were obtained from hospital record data. RESULTS: Children with head circumference at birth of 37 cm or greater had (unadjusted) odds of asthma that were 1.8 (P < 0.01) to 3.0 (P < 0.0001) times higher than the odds for children of lesser head circumference. However, risks of asthma were not related to other perinatal measures including birthweight, gestational age or length or ratios of these measures. There were no consistent associations between perinatal measures and other measures of childhood atopy including eczema, allergic rhinitis and other allergies. The associations between head circumference and asthma risks persisted when due allowance was made for potentially confounding social and perinatal factors. CONCLUSIONS: It is concluded that large head circumference at birth may be associated with increased risks for the development of asthma. Possible explanations for the linkages between head circumference and asthma risks are considered.

Adolescent↗
PubMed1997

Is infant immunization a risk factor for childhood asthma or allergy?

The Christchurch Health and Development Study comprises 1,265 children born in 1977. The 23 children who received no diphtheria/pertussis/tetanus (DPT) and polio immunizations had no recorded asthma episodes or consultations for asthma or other allergic illness before age 10 years; in the immunized children, 23.1% had asthma episodes, 22.5% asthma consultations, and 30.0% consultations for other allergic illness. Similar differences were observed at ages 5 and 16 years. These findings do not appear to be due to differential use of health services (although this possibility cannot be excluded) or con-founding by ethnicity, socioeconomic status, parental atopy, or parental smoking.

Adolescent↗
PubMed1997

Worldwide variations in prevalence of symptoms of allergic rhinoconjunctivitis in children: the International Study of Asthma and Allergies in Childhood (ISAAC).

BACKGROUND: As part of the International Study of Asthma and Allergies in Childhood (ISAAC), prevalence surveys were conducted among representative samples of school children from locations in Europe, Asia, Africa, Australia, North and South America. SUBJECTS: 257,800 children aged 6-7 years from 91 centres in 38 countries, and 463,801 children aged 13-14 years from 155 centres in 56 countries. METHODS: Written symptom questionnaires were translated from English into the local language for self-completion by the 13-14-year-olds and completion by the parents of the 6-7-year-olds. Rhinitis was described as a problem with sneezing, or a runny, or blocked nose when you (your child) DID NOT have a cold or the flu. Additional questions were asked about rhinitis associated with itchy-watery eyes, interference with activities and a history of hay fever ever. RESULTS: The prevalence of rhinitis with itchy-watery eyes ("rhinoconjunctivitis") in the past year varied across centres from 0.8% to 14.9% in the 6-7-year-olds and from 1.4% to 39.7% in the 13-14-year-olds. Within each age group, the global pattern was broadly consistent across each of the symptom categories. In centres of higher prevalence there was great variability in the proportion of rhinoconjunctivitis labelled as hay fever. The lowest prevalences of rhinoconjunctivitis were found in parts of eastern Europe, south and central Asia. High prevalences were reported from centres in several regions. CONCLUSION: These results suggest substantial worldwide variations in the prevalence and labelling of symptoms of allergic rhinoconjunctivitis which require further study. These differences, if real, may offer important clues to environmental influences on allergy.

Adolescent↗
PubMed1996

Trial of a "credit card" asthma self-management plan in a high-risk group of patients with asthma.

BACKGROUND: The "credit card" asthma self-management plan provides the adult asthmatic patient with simple guidelines for the self-management of asthma, which are based on the self-assessment of peak expiratory flow rate recordings and symptoms. OBJECTIVE: The study was a trial of the clinical efficacy of the credit card plan in a high-risk group of asthmatic patients. METHODS: In this "before-and-after" trial, patients discharged from the emergency department of Wellington Hospital, after treatment for severe asthma were invited to attend a series of hospital outpatient clinics at which the credit card plan was introduced. Questionnaires were used to compare markers of asthma morbidity, requirement for emergency medical care, and medication use during the 6-month period before and after intervention with the credit card plan. RESULTS: Of the 30 patients with asthma who attended the first outpatient clinic, 26 (17 women and 9 men) completed the program. In these 26 participants, there was a reduction in both morbidity and requirement for acute medical services: specifically, the proportion waking with asthma more than once a week decreased from 65% to 23% (p = 0.005) and the proportion visiting the emergency department for treatment of severe asthma decreased from 58% to 15% (p = 0.004). The patients attending the clinics commented favorably on the plan, in particular on its usefulness as an educational tool for monitoring and treating their asthma. CONCLUSIONS: Although the interpretation of this study is limited by the lack of a randomized control group, the findings are consistent with other evidence that the credit card asthma self-management plan can be an effective and acceptable system for improving asthma care in a high-risk group of adult patients with asthma.

Adolescent↗
PubMed1996

Problems of measuring asthma prevalence.

This review considers the issues involved in measuring the community prevalence of asthma, particularly in the context of international comparisons. We argue that there is no gold standard definition for measuring asthma prevalence, and discuss the currently available methods of case ascertainment. Prevalence studies, if they are to be generalizable, need to involve large sample sizes with high response rates. This necessitates methods that are simple, inexpensive and practicable, but also as sensitive and specific for asthma as possible. We discuss some of the issues that are specific to comparisons of asthma prevalence between diverse populations, and suggest that large surveys using written or video questionnaires of self reported symptoms validated in all of the target populations are the method of choice.

Asthma↗
PubMed1996

Cellular infiltration of the airways in asthma of varying severity.

We have tested the hypothesis that airway infiltration by inflammatory cells reflects the severity of asthma by comparing the inflammatory cell infiltrates in fatal severe asthma and in subjects with mild to moderate asthma who died of unrelated causes. Sections of lung tissue from 25 fatal asthma cases and eight asthmatics who died of unrelated causes were immunostained by monoclonal antibodies (mAbs) using streptavidin-biotin peroxidase technique. The following cells were identified: mast cells (AA1:tryptase), eosinophils (EG1:stored cationic protein and EG2: secretory form of cationic protein), monocytes/macrophages (CD68), neutrophils (elastase), CD3+ and CD8+ T cells (CD3 polyclonal Ab and CD8+ mAb, respectively). Positive cells were counted in the epithelium and airway wall. The airways were divided into two groups: larger airways with internal perimeter (Pi) > 2 mm and smaller airways with Pi < 2 mm. All airways together were studied first, followed by larger and smaller airways examined separately. The numbers of intraepithelial CD3+ T cells were significantly lower in fatal asthma than in mild-moderate asthma both when all airways were considered (0.35 versus 0.86 cells/mm, p = 0.034) and in the larger airways alone (0.08 versus 1.05 cells/mm, p = 0.039). The numbers of EG1- and EG2-positive eosinophils infiltrating the airway wall of the larger airways were greater in fatal asthma than in mild-moderate asthma (78.2 versus 22.8 cells/mm2, p = 0.012 and 138.1 versus 31.7 cells/mm2, p = 0.022). In the smaller airways no significant difference was found between the two groups. We conclude that in fatal asthma there is a redistribution of CD3+ T cells away from the epithelium and proximal enhancement of the eosinophil inflammatory infiltrate. These findings have implications for the pathophysiology of asthma that results in death.

Adolescent↗
PubMed1996

Immunopathology of fatal soybean dust-induced asthma.

A hypothesis was postulated that the characteristic clinical course of fatal soybean asthma may be reflected by specific immunopathological findings. Seven cases of fatal soybean dust-induced asthma from Barcelona, Spain were compared with 25 fatal asthma cases from New Zealand. Sections of lung tissue were stained by monoclonal antibodies using standard streptavidin-biotin peroxidase technique. The following cell types were identified: mast cells, "activated" eosinophils, neutrophils, monocytes/macrophages, CD3+ T-cells and CD8+ T-cells. The positively staining cells were counted in the epithelium and the submucosa and their numbers expressed per mm and mm2, respectively. The airways were divided into larger (internal perimeter (Pi) > 2 mm) and smaller (Pi < 2 mm). Firstly, all airways were studied together; and subsequently, larger and smaller airways were studied separately. Differences in the numbers of mast cells, eosinophils, neutrophils and monocytes/macrophages between the two groups were not significant. The numbers of CD3+ and CD8+ T-cells were significantly reduced in fatal soybean asthma when all airways were taken together. In larger airways, the difference was not significant in the epithelium, but was significant in the submucosa for CD3+ cells. CD8+ cells were significantly reduced in fatal soybean asthma both in the epithelium and the submucosa. The cell counts in smaller airways were not significantly different either in the epithelium or in the submucosa for CD3+ cells. The numbers of CD8+ cells were not different in the epithelium, but were significantly reduced in the submucosa of fatal soybean asthma cases. We conclude that the numbers of CD3+ and CD8+ T-cells are substantially reduced in fatal soybean asthma. These data together with the clinical features of the fatal attack suggest a different mechanism(s) from that described for most asthma deaths, probably involving anaphylaxis.

Adult↗