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Biomedical subjects

M R Sears

Publications and source records attributed to M R Sears.

At least 127 records · Page 7Linked to original sources
PubMed1987

Childhood asthma in New Zealand.

To determine the prevalence and severity of childhood asthma in New Zealand we studied 815 children from a birth cohort by questionnaire, clinical examination and pulmonary physiological measurements at age 9 years. More than 19% of the sample had experienced wheezing in the previous year, and 11% had wheezed in the month before assessment. In all, 220 of 815 children (27.1%) had had wheezing episodes by age 9; in 34 (4.2%) episodes had been of sufficient frequency to warrant regular anti-asthma treatment. Only 32% of all wheezing children were reported by their parents to suffer from asthma, and, in groups matched for frequency of symptoms, treatment given for wheezing was influenced strongly by whether or not the label of 'asthma' had been given. The detailed history provided most information useful in diagnosing asthma; clinical examination, peak flow records, spirometry and bronchial provocation testing provided only limited additional information. A wide spectrum of frequency and severity of recurrent wheezing disorders was evident in New Zealand children. Throughout all degrees of severity, prevalence rates appeared higher than those reported in studies from the United Kingdom.

Asthma↗
PubMed1987

Use of anti-asthma drugs in New Zealand.

Increased sales of anti-asthma drugs, and a second "epidemic" of asthma mortality, raised concerns about the management of asthma in New Zealand. To study this, prescriptions were obtained from randomly selected pharmacies to identify 235 patients receiving one common anti-asthma drug, 175 of whom were willing to be interviewed. The authors considered that 80% had asthma, and only 20% suffered primarily from chronic bronchitis or emphysema. The increased sales of anti-asthma drugs could not therefore be explained by their increasing use in treatment of other respiratory disorders. One third of the identified asthmatic subjects experienced daily symptoms despite regular drug treatment. Inhaled corticosteroids were used by only 42% of this group with persistent symptoms. Regular or short course oral corticosteroids, with or without inhaled steroids, had been required by 49%. All patients with domiciliary nebulisers appeared to use these appropriately, and most had peak expiratory flow meters. Despite the increased sales of anti-asthma drugs, corticosteroids appear to be as much underused in patients with chronic asthma in the community as in those who die of their disease.

Adolescent↗
PubMed1986

Asthma mortality: comparison between New Zealand and England.

Causes for the high mortality from asthma in New Zealand were investigated by comparing deaths from asthma in caucasian subjects aged 15-64 in New Zealand with those from asthma in the same age group in two regions in England. There were no significant differences in the accuracy of death certification. The verified asthma mortality in New Zealand (4.2/100,000) was over twice that in England. Many characteristics of patients and management, including poor compliance with treatment and deficiencies in long term and emergency care, were qualitatively similar in the two countries. New Zealand had an apparently higher rate of non-preventable deaths from asthma, suggesting a greater severity of asthma in New Zealand. In both countries, however, most deaths were associated with poor assessment, underestimation of severity and inappropriate treatment (over-reliance on bronchodilators and underuse of systemic corticosteroids), and delays in obtaining help. A greater frequency of some of these deficiencies in management remains a possible additional explanation for part of the excess mortality in New Zealand.

Adolescent↗
PubMed1986

Accuracy of certification of deaths due to asthma. A national study.

In a two-year study of asthma mortality in New Zealand conducted between August 1981 and July 1983, the certified cause of death and its subsequent statistical coding was compared with the opinion of a panel of respiratory physicians who had made detailed enquiry into the medical history and circumstances surrounding the death of each patient. When the panel's opinion was taken as the reference standard, the national health statistics overestimated asthma mortality for all age groups by 26.0%. For patients aged 15-64 years, the net overestimate was 12.9%, no greater than that found in a similar study in this age group in the United Kingdom. Failure of certifying doctors and coroners to follow appropriate procedures for identification of the primary condition leading to death, or misdiagnosis of other lung disease as asthma, accounted for most inaccuracies in certification. In patients under age 35 years, certification and statistical coding of asthma death was considered accurate in 97.8% of all cases, but accuracy declined with increasing age. The high New Zealand asthma mortality rate, especially in young people, could not be explained by inaccuracies in death certification or statistical coding.

Adolescent↗
PubMed1986

Deaths from asthma in New Zealand.

We report the first complete population based study of childhood deaths due to asthma. All deaths ascribed to asthma in New Zealand children aged 0-14 were investigated as part of a two year national study of mortality from asthma. The 16 children who died from asthma all developed asthma by the age of 4; 15 had a family history of asthma, and 12 had associated atopic disorders. Disturbed pyschosocial relationships were evident in eight families. Seven children died in less than three hours from the onset of their final attack. All children died outside hospital. Mortality from asthma in Maori children (3.14 per 100 000) was five times that of European children. With hindsight, factors which if avoided could have led to a different outcome were identified in eleven cases. The circumstances surrounding these deaths were similar to those described for adults with asthma; this study, however, underlines the importance of parental care and knowledge in the management of children with asthma. Inadequate long term medical care, underassessment of severity by family and doctors, failure of the family to call for help when required, and inadequate responses of medical services contributed to the fatalities. Excess beta2 sympathomimetic dosage or overreliance on home nebulisers were uncommon. Most childhood deaths from asthma should be prevented by increased family awareness, better assessment of severity, improved long term treatment, and rapid access to emergency medical care.

Adolescent↗
PubMed1986

Prevalence of bronchial reactivity to inhaled methacholine in New Zealand children.

The prevalence of bronchial hyperreactivity to inhaled methacholine and of a clinical history of symptoms of asthma was determined in a birth cohort of 9 year old New Zealand children. A history of current or previous recurrent wheezing was obtained in 220 of 815 children. Of 800 who had spirometric tests, 27 (3.4%) had resting airflow obstruction (FEV1/FVC less than 75%). Methacholine challenge was undertaken without problem in 766 children, the abbreviated protocol being based on five breaths and four concentrations. A fall in FEV1 of more than 20% was observed in 176 children (23% of challenges, 22% of the full cohort) after inhalation of methacholine in concentrations of up to 25 mg/ml. The prevalence of bronchial reactivity in children with symptoms was related to the frequency of wheezing episodes in the last year, and the degree of reactivity to the interval since the last episode. Sixty four children (8.0%) with no history of wheeze or recurrent dry cough were, however, also responsive to methacholine 25 mg/ml or less, while 35% of children with current or previous wheezing did not respond to any dose of methacholine. Bronchial challenge by methacholine inhalation was not sufficiently sensitive or specific to be useful as a major criterion for the diagnosis of asthma in epidemiological studies. The occurrence of airway reactivity in children without symptoms of asthma, however, raises the possibility that adult onset asthma and the development of airways obstruction in some subjects with chronic bronchitis could have origins in childhood.

Asthma↗
PubMed1986

Why are deaths from asthma increasing?

Asthma mortality rates have declined only slowly since 1960, and recently have increased in some countries. Deaths in New Zealand's 5-34 year olds showed a sustained increase from 1977 to 1982. In the western United States, asthma mortality in older subjects increased from 1979 to 1982. In 15-44 year olds in England and Wales, mortality rates for females are now lower than in 1960, but rates for males are not. Current asthma mortality rates for Canadian 5-34 year olds are twice those reported a decade ago. A 2-year national study of all New Zealand patients under the age of 70 whose deaths were certified as due to, or related to, asthma found differences in verified asthma mortality rates among races (Maoris 18.9, Pacific Island Polynesians 9.4, and Europeans 3.4 per 100,000); the higher non-European rates explained 36% of the 'excess' New Zealand mortality compared with England. Errors in certification led to a 13% net overestimate of asthma mortality in both countries, but certification was highly accurate in 5-34 year olds. The increase in asthma mortality in the younger age groups is not an artefact of certification or coding, but is real and substantial. Although factors common to previous studies--poor patient compliance, inadequate assessment and therapy, overreliance on bronchodilators and underuse of corticosteroids, and delays in obtaining help--were frequently recognized, no single cause was found to explain the three-fold greater mortality in New Zealand compared with England.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

Asthma mortality in New Zealand: a two year national study.

The epidemic of deaths from bronchial asthma in New Zealand was investigated by a two-year national review of all deaths of persons under 70 years where "asthma" appeared in part I of a death certificate or in a coroner's report of cause of death. Information about the patients, the characteristics and management of their asthma and the circumstances of the fatal episode was obtained by interviewing relatives and general practitioners and perusal of hospital records. The reviewing panel of the asthma task force of the Medical Research Council considered 271 of the 342 deaths studied were due to asthma. A high national asthma mortality rate (5.1 per 100 000) was confirmed, with rates for Maoris (18.9) and Pacific Islanders (9.4) considerably higher than that for Europeans (3.4 per 100 000). After standardising for age and ethnic groups, there remained a threefold variation in mortality rates among health districts suggesting regional differences in prevalence, severity or management of asthma. No single cause for these high mortality rates was found. One-quarter of the deaths occurred in patients who had had previous life threatening attacks. Excessive use of bronchodilator drugs did not account for the high mortality rates, but inappropriate prolonged use of a home nebuliser may have delayed institution of other therapy in a few cases.

Adolescent↗
PubMed1985

Physical exercise and resistive breathing training in severe chronic airways obstruction--are they effective?

Twenty-one patients with severe chronic irreversible airflow obstruction (FEV1 consistently less than 1.2 l) were allocated randomly to one of two training programmes designed to reduce respiratory disability or a placebo training control group. Daily structured physical exercise, twice daily inspiratory muscle training by resistive breathing, or daily placebo training were undertaken for 10 weeks, and the effects on lung function, exercise capacity, respiratory symptoms and psychological state compared. Maximal work achieved on a progressive bicycle exercise test was significantly increased in all groups (36%, 23% and 34% respectively) and global improvement in mood also occurred. There was no significant change in respiratory symptom score, static lung function tests or 12 min walking distance. Neither form of active treatment showed superiority over placebo training.

Airway Obstruction↗