Asthma mortality and death certification in Northern Ireland

Fatal asthma; is it still an epidemic?

BACKGROUND

Asthma mortality has declined since the 1980s. Nevertheless the World Health Organization (WHO) identified asthma as responsible for 225.000 deaths worldwide in 2005, and 430.000 fatal cases are expected by 2030. Some unexpected and concentrated fatal asthma events all occurred between 2013 and 2015 in Veneto, a North Eastern region of Italy, which prompted a more in-depth investigation of characteristics and risk factors.

METHODS

A web search including key words related to fatal asthma in Italy between 2013 and 2015 has been performed. Concerning the cases that occurred in Veneto, subjects' clinical records have been evaluated and details about concomitant weather conditions, pollutants and pollen count have been collected.

RESULTS

Twenty-three cases of asthma deaths were found in Italy; 16 of them (69%) occurred in the Veneto Region. A prevalence of male and young age was observed. Most of patients were atopic, died in the night-time hours and during the weekends. The possible risk factors identified were the sensitization to alternaria, previous near fatal asthma attacks and the incorrect treatment of the disease. Weather condition did not appear to be related to the fatal exacerbations, whereas among the pollutants only ozone was detected over the accepted limits. Smoking habits, possible drug abuse and concomitant complementary therapies might be regarded as further risk factors.

DISCUSSION

Although not free from potential biases, our web search and further investigations highlight an increasing asthma mortality trend, similarly to what other observatories report. The analysis of available clinical data suggests that the lack of treatment more than a severe asthma phenotype characterizes the fatal events.

CONCLUSIONS

Asthma mortality still represents a critical issue in the management of the disease, particularly in youngsters. Once more the inadequate treatment and the lack of adherence seem to be not only related to the uncontrolled asthma but also to asthma mortality.

Asthma deaths; persistent and preventable mortality

Bronchial asthma remains a significant cause of mortality at all ages, despite the increased understanding of its pathogenesis and the range of drugs available for its treatment. Changes in therapeutic management can influence death rates and constant surveillance, combined with high-quality post mortem investigations, is essential. Disease severity, poor disease management and adverse psychosocial circumstances are all risk factors for asthma mortality. Bronchial asthma causes characteristic histological changes in the mucosa of the airways which are present even before the clinical diagnosis of asthma can be made. These include fibrous thickening of the lamina reticularis of the epithelial basement membrane, smooth muscle hypertrophy and hyperplasia, increased mucosal vascularity and an eosinophil-rich inflammatory cell infiltrate. In addition, mucoid plugging of the airway lumen is frequently associated with fatal asthma. The recognition of these changes can allow the diagnosis of asthma to be made for the first time at autopsy, in those cases where asthma goes undiagnosed in life. Acute severe asthma may be accompanied by pneumothorax and surgical emphysema of the mediastinum. Disorders which may mimic asthma include pulmonary embolism, chronic obstructive pulmonary disease and anaphylaxis, but careful post mortem examination and appropriate investigations should reveal the true cause of death.

Accuracy of recorded asthma deaths in Denmark in a 12-months period in 1994/95

Many studies of asthma mortality rely on official registration. The aim of this study was to evaluate the accuracy of death certificates, where asthma was coded as cause of death. In a 12-month period, medical information on all subjects with asthma officially coded as the underlying cause of death in Denmark, was obtained by reviewing hospital records, contacting general practitioners and sometimes close relatives. A panel of four pulmonologists each examined the obtained information and independently assessed the cause of death. Of a total of 218 death certificates, 39 were excluded as the cause of death could not be validated. In 16 (9%) of the subjects death from asthma was judged to be the definite cause of death and in 12 (7%) death from asthma was possible. Of 151 non-asthma deaths coded as due to asthma, 109 were judged to have suffered or died from COPD and 14 from heart disease. The accuracy of Danish death certification in asthma deaths is poor, especially in the elderly, where COPD is often classified as asthma. We conclude that the true asthma mortality in Denmark is substantially lower than officially recorded.

Scottish Confidential Inquiry into Asthma Deaths (SCIAD), 1994-6

BACKGROUND

There have been important changes in the organisation of care for patients with asthma since asthma deaths were studied in the 1980s by the British Thoracic Association (BTA), with greater emphasis on long term control of symptoms and the use of preventive therapy. Recent trends in routine statistics show a decline in population death rates.

METHODS

A confidential review was undertaken of general practice and hospital records and interviews with general practitioners of patients dying in mainland Scotland between January 1994 and December 1996 with a principal diagnosis of asthma recorded by the Registrar General's Office. Panel assessment of the cause of death was carried out and a number of possible adverse factors were identified. The data from the 15-64 year age group were compared with similar data from the earlier study by the BTA.

RESULTS

Over the three year period 95 deaths of 235 studied (40%) were confirmed as being due to asthma. Taking account of different methods of case ascertainment used in the BTA and this study, a fall in the calculated rate of "deaths assessed as due to asthma" was found from 2.51 (95% CI 2.34 to 2.68) per 100,000 population in 1979 to 1.26 (95% CI 1.19 to 1.33) per 100,000 population in 1994-6. Fewer individual adverse factors were identified in clinical management, with appropriate routine management in 59% and management of the final attack satisfactory in 71%. Patient factors such as poor compliance, lack of peak expiratory flow (PEF) measurements, and overuse of reliever medication without inhaled corticosteroids, and psychosocial problems, notably depression, were confirmed as important contributing factors. Four of five patients under 16 years of age who died were found to have problems with routine management.

CONCLUSIONS

This population based study documents important improvements in the standard of asthma care as well as a significant decline in the rate of deaths due to asthma over a period during which the organisation of care has changed and the chronic nature of the disease has been acknowledged. Strategies which might have a further impact include the greater use of PEF recordings, particularly during acute attacks, to document recovery, prescription monitoring of the underuse of inhaled corticosteroids, consideration of the use of combined preparations where persistent overuse of bronchodilators is occurring, and increased input for young patients whose routine management is proving difficult.

The natural history of asthma in adults: the problem of irreversibility

Asthma is common, affecting 5% to 10% of adults; asthma is progressive, leading to irreversible obstruction in 80% of elderly patients; and asthma is complex, often complicated by coexisting lung diseases. This loss of lung function results from 4 independent pathologic conditions: (1) airway remodeling, especially in the small airways, from the lymphocytic-eosinophilic inflammation that characterizes asthma; (2) bronchiectasis; (3) postinfectious pulmonary fibrosis; and (4) emphysema and chronic bronchitis from tobacco smoke. Deterioration in lung function develops faster in nonallergic patients with intrinsic asthma during the period shortly after onset of asthma and in older patients. About 4% of patients die of asthma, and most are elderly. Death most often results from complications of irreversible obstruction or cardiotoxicity of bronchodilator therapy. More research is needed to improve therapy for preventing remodeling of small airways, to confirm the frequency of bronchiectasis and postinfectious fibrosis and to determine their causes, and to develop diagnostic criteria to identify these complications. Meanwhile, clinicians treating adult asthmatic patients need to be aggressive in preventing the damage from cigarette smoke; in immunizing for influenza and pneumococcus infection and identifying and treating respiratory infections, particularly at times of acute exacerbations; in diagnosing and managing bronchiectasis; and in objectively confirming the efficacy of asthma therapy to prevent illness from overtreatment with glucocorticoids and bronchodilators.

The necessary role of the autopsy in cardiovascular epidemiology

The autopsy rate in the United States today is remarkably low, with proportionally fewer autopsies for natural causes of death. Consequently, most cardiovascular epidemiology studies do not use autopsy data and rely on death certificates, medical records, questionnaires, and family interviews as sources of mortality information. These practices introduce a high degree of variability and uncertainty regarding cause of death. This review illustrates the necessity for increased use of autopsies in cardiovascular epidemiology by critically evaluating other measures of cardiovascular disease (CVD) incidence. We evaluated the literature regarding CVD as cause of death and conducted discussions with cardiologists, pathologists, and epidemiologists. No attempt was made for meta-analysis. This review shows the limited reliability of death certificates, medical records, and interviews as sources of mortality statistics. In addition, the autopsy's role in clearly indicating the presence of CVD is illustrated. The autopsy used in conjunction with medical records is the only reliable means for establishing cause of death from CVD. There is an urgent need to reassess the current dependence of statistical mortality data on death certificates and other inadequate sources of CVD incidence. Death certificates, in general, are inadequately monitored for quality control and appropriate administrative oversight. With an increase in the number of hospitals performing no autopsies to investigate cause of death, a uniform national autopsy database is needed.

[The evolution of mortality due to asthma in the age groups 5-34 and 5-44. Spain, 1975-1991]

BASICS: Mortality caused by asthma has increased in most occidental countries, but its evolution has been unknown for Spain during the last few years.

METHOD

Variations of mortality caused by asthma of the age groups from 5 to 44 (age in which it is considered an avoidable cause) and from 5 to 34 years of age (when the diagnosis of disease by asthma is more valid) are analysed in Spain from 1975 to 1991. The data of diseases by asthma (CIE-9th-493) have been supplied by the National Institute of Statistics.

RESULTS

The rates of crude mortality by asthma, +/- standard error, for the group from 5 to 34 years of age oscillate between 0.09 +/- 0.02 every 100,000 inhabitants in 1979 to 0.30 +/- 0.04 in 1989. With the standardized rates according to age, we could observe an increase in the mortality caused by asthma for the group from 5 to 34 years of age in 1% (confidence interval 95%, 0.2% to 1.9%) each year since 1981. This increase is not significant for the group from 5 to 44 years of age: 0.6% (IC95% -0.01 to 1.3), due to a negative tendency in the group from 35 to 44 years of age. In the period 1987-1989 there was a significant increase in the group from 5 to 34 years of age (p < 0.001) which could not be explained by the temporary tendency.

CONCLUSIONS

We conclude that mortality caused by asthma in these age groups in Spain is infrequent and the rates stay between the lowest registered in the developed world, although, as in most countries, there is a slight increase in the age from 5 to 34 years. The increase of the prevalence and severity of asthma could explain such increase, but this would require specific studies.

Asthma deaths confounded by substance abuse. An assessment of fatal asthma

BACKGROUND

The Chicago region has been identified as having a very high death rate from asthma in patients aged 5 to 34 years. We investigated circumstances surrounding the fatal attack to determine whether the death was from asthma, of indeterminate cause, or coincidental to asthma.

METHODS

Cases of asthma deaths from the Office of the Medical Examiner, where the deceased were younger than 46 years of age, were used to determine clinical, toxicologic, and pathologic findings relevant to asthma. Toxicologic results were compared with homicide victims.

RESULTS

From 102 cases of fatal asthma, 46 cases were classified as deaths from asthma and 17 cases were considered probably from asthma as toxicologic tests were negative. Twenty-three cases were of indeterminate cause in that the acute respiratory symptoms were accompanied by substance use or alcohol consumption. Fourteen cases were not caused by asthma but were substance related, primarily cocaine. Overall, 29 of 92 (31.5%) cases were confounded by substance abuse or alcohol ingestion, which is almost as high as in homicide victims (38/82 [46.3%]). Mucus plugging of bronchi and or hyperinflation in fatal asthma occurred in 65 of 93 (69.9%) cases. Anti-inflammatory medications were being utilized by just two patients. Sufficient information was available to identify potentially fatal asthma in 6 of 20 cases (30%).

CONCLUSION

Some of the reported rise in asthma deaths is a reflection of substance use or alcohol consumption similar to that seen in victims of homicide. In that patients with asthma are hypersensitive to alpha-adrenergic agonists, the use of cocaine may be especially dangerous and induce fatal ventricular dysrhythmias.

Accuracy of recording of deaths from asthma in the UK: the false negative rate

BACKGROUND

A study was carried out to determine the extent to which asthma deaths are wrongly attributed to another cause on UK death certificates.

METHODS

Deaths from all causes occurring anywhere in the UK were identified amongst 2382 subjects aged 16-64 years within three years of discharge following hospital treatment for asthma (ICD9 493) in hospitals in the South East Thames region. The deaths were reviewed by an expert panel to assess the proportion of asthma deaths identified by the panel which were attributed to another cause of death on the death certificate (false negatives).

RESULTS

Eighty five deaths from all causes were identified in a mean follow up period of two years and three months. In 61 cases (72%) there was sufficient information for the expert panel to be confident about the cause of death. The panel identified 22 deaths from asthma, four of which were certified as non-asthma deaths (two as deaths from chronic obstructive pulmonary disease (COPD) and two as deaths from cardiovascular disease). The proportion of false negative death certificates was four of 22 (18%, 95% confidence interval (CI) 5 to 40).

CONCLUSIONS

There is evidence that asthma deaths in the UK are wrongly certified as deaths from both chronic obstructive pulmonary disease and diseases of the cardiovascular system.

Death from airways obstruction: accuracy of certification in Northern Ireland

BACKGROUND

Studies of mortality from asthma and chronic obstructive pulmonary disease (COPD) have relied on death certification or registration for case finding. The aim of this study was to determine the accuracy of death certification and registration in asthma and COPD.

METHODS

All death certificates in Northern Ireland for 1987 where asthma or COPD (defined as International Classification of Diseases 9th Revision (ICD9) 490, 491, 492, 496) were listed in part I or part II were identified. The following certificates were then selected for further investigation: those mentioning asthma for all ages, those mentioning COPD for ages less than 56 years, and a 50% sample of those mentioning COPD aged 56-75 years. For these selected deaths the general practitioners' case notes, hospital records, and necropsy findings were reviewed. Questionnaires detailing the clinical history and circumstances of death were completed by the general practitioner by post and by a close relative or associate of the deceased (doctor administered) if, after initial investigation, the death was likely to be due to COPD or asthma. A panel of two respiratory physicians reviewed each death and, using clinical diagnostic criteria, assessed the accuracy of the registered cause of death.

RESULTS

Of 50 registered asthma deaths 43 were confirmed as being due to asthma. In nine registered deaths from COPD in cases aged less than 56 years one was confirmed as COPD, two as asthma, and six as other respiratory conditions. Of 105 registered deaths from COPD in cases aged 56-75, 42 were confirmed as COPD, 27 as asthma, eight as other respiratory conditions, and 28 as other causes. Although few errors in registration were found, 21% of certificates mentioning asthma and 38% of certificates mentioning COPD but not asthma in part I were subject to variable application of the classification rules by the registering officers. For all deaths under 75 years of age in Northern Ireland in 1987 where either asthma or COPD was mentioned anywhere on the death certificate, the estimated sensitivity and specificity of the registered cause of death in predicting the "true" cause of death were 29% and 98.6% for asthma and 69% and 70% for COPD.

CONCLUSIONS

In a population of subjects where asthma or COPD was mentioned anywhere on the death certificate, the registered cause of death is a relatively poor indicator of the "true" cause of death for both asthma and COPD. Variation occurred in the application of death classification rules by registration officers. Many deaths certified and registered as COPD could have been called asthma using current standards of clinical diagnosis. In studies investigating risk factors for deaths from asthma, case finding should consider deaths registered as COPD.