Biomedical subjects

S M Alcock

Publications and source records attributed to S M Alcock.

7 recordsLinked to original sources

PubMed2002

Mortality in asthmatics over 15 yrs: a dynamic cohort study from 1983-1998.

The Darlington and Northallerton long-term asthma study observes outcome in asthmatics in the light of potential explanatory variables recorded prospectively. This paper reports changes in mortality during the study, and assesses the relevant risk factors. All asthmatics attending secondary care were recruited at 5-yr intervals from 1983 and reviewed 5 yrs later. Demographic and functional variables, including a formal estimate of best function were recorded prospectively. The dynamic cohort comprised 1,148 asthmatics with 95% follow-up, enabling 612 observations in the period 1983/1988, 774 in 1988/93 and 823 in 1993/98, with 101, 111 and 100 deaths respectively. Principal risk factors for mortality were lower social class and best forced vital capacity. Mortality relative to 1983 halved by 1993/98 and was reduced against the Darlington population, despite an entry forced expiratory volume in one second of 84.7%. There was no change in predictive value of risk factors during the study period, or with date of entry. This study demonstrates a consistent reduction in mortality, which was not entirely a survivor effect, but may be associated with changes in management. By 1993/98 mortality approximated to that of the local reference population despite a lower than predicted forced expiratory volume in one second.

Asthma↗

PubMed1998

The Darlington and Northallerton Prospective Asthma Study: best function predicts mortality during the first 10 years.

The Darlington/Northallerton prospective study of asthmatics referred to secondary care started in 1983, with review and new entry at 5-yr intervals. The principal outcome measures are: mortality (presented here), best function and therapeutic step. All adult asthmatics with > or = 15% peak flow (PEF) reversibility to > or = 200 l min-1 were included. Socio-demographic variables, PEF and spirometry were recorded prospectively. Best vital capacity (FVC) and PEF were assessed according to protocol. The mortality of the original cohort after 10 yr was expressed as standardized mortality ratio (SMR) against the local population, with history and pulmonary function at entry as explanatory variables. Ninety-five per cent follow-up was achieved in 628 subjects, with 173 deaths (29.1% of those traced). The excess death rate was nearly 50% (SMR 1.47, 95% CI 1.26-1.71), with 56% of deaths due to respiratory disease (expected 10%). After allowance for age and sex, there was a consistent inverse relationship between mortality and entry best FVC, increased risk of death 1.51 (95% CI 1.33-1.72) per 10% deficit of best FVC predicted. The risk of respiratory death was eight times greater, and of non-respiratory death three times greater, in the lowest compared with the highest quartile of best FVC. There were no interactions with smoking, but possible enhancement of the effect in the socially deprived. Best FVC was a particularly powerful predictor of mortality in subjects < 65 years at entry, in whom 64% of the excess deaths occurred. Most of the excess in respiratory deaths was not due to acute severe asthma but to the development of chronic obstructive pulmonary disease (COPD), as defined functionally, irrespective of smoking habit which made no further contribution to mortality.

Adult↗

PubMed1998

Symptoms and pulmonary function in asthma.

The relationship between symptoms and pulmonary function in asthma is important if the latter is to be held relevant to management guidelines and their audit. Associations between reported symptoms, pulmonary function and therapy were studied in 824 asthmatics (mean FEV1 75.4% predicted; best FEV1 84.6% predicted; and actual/best peak flow (PEF) 87.5%). Bronchodilator usage (reflecting symptomatic wheeze) was evenly distributed up to eight times daily; 22.5% of subjects had nocturnal disturbance and 46.3% persistent daytime symptoms. The univariate relationships between symptoms and function were generally closer with best rather than actual/best. They were further explored using quintiles of function. Symptoms were consistently less as best function increased, but were highly significantly greater in the fifth than in the third and fourth quintiles of actual/best FEV1. There was a trend to a similar U-shaped relationship of actual/best PEF with nocturnal disturbance and daytime symptoms. Best function is a good determinant of expected symptom load in an asthmatic population. Below 85% actual/best function reflects the prevalence of symptoms. In asymptomatic patients a level of at least 85-90% is a useful check of physiological control but will not exclude some symptomatic patients, irrespective of best function.

Adult↗

PubMed1998

Management and control of asthma as assessed by actual/best function and corticosteroid use 1980-1993/4.

This study aimed to determine whether the changes in practice in the management of asthma since the early 1980s have improved standards (as assessed by higher actual/best function) and reduced the need for oral corticosteroids. All asthmatic outpatients were reviewed in 1980, 1983, 1988/89 and 1993/94. Therapeutic step, defined by suppressive medication alone, actual and best peak expiratory flow (PEF) were recorded. Cohorts from 1980, 1983 and 1988/89 were identified in whom best function was established on all subsequent occasions. Changes in practice demonstrated by cross-sectional review of all subjects were interpreted with the aid of longitudinal analysis of the cohorts. Attendance increased from 463 in 1980 to 772 in 1993/94. Between 1983 and 1993/94, the proportion maintained on inhaled corticosteroids increased from 49 to 84% with increased use of higher doses. Mean actual/best PEF rose from 80 to 87%, improving at each therapeutic step. The proportion needing rescue oral corticosteroids fell from 47 to 35% and maintenance oral corticosteroids from 20 to 9%. In the cohorts, there was a similar reduction in use of rescue corticosteroids, but not of maintenance oral corticosteroids. The study confirmed an increase in the use and dose of inhaled corticosteroids, and a better outcome at all treatment steps. The fall in the proportion of subjects dependent on oral corticosteroids was due to attrition, rather than weaning in later years.

Administration, Inhalation↗

PubMed1997

Sputum and pulmonary function in asthma.

STUDY OBJECTIVE: To assess the relevance of sputum production to pulmonary function, in particular, persistent obstruction in patients with a primary clinical diagnosis of asthma. DESIGN: Cross-sectional study of all patients currently followed up in secondary care in a defined locality. SETTING: National Health Service and private clinics in north-east England. PATIENTS: All attenders, aged 18 years or older, with asthma, confirmed by reversibility of peak expiratory flow (PEF) by > or =15% and to > or =200 L/min. INTERVENTIONS: Pro forma history. Pulmonary function at attendance. Assessment of best function according to protocol. Measurement of actual FEV1, FVC, and PEF at attendance. MEASUREMENTS AND RESULTS: We studied 772 subjects; 387 (50%) were male; mean age was 55 years; atopic, 51%; current smokers, 11.5%; ex-smokers, 36%; and never smokers, 52.5%. Best pulmonary function was lower in chronic sputum producers (PEF, 83.2 vs 95.8; FVC, 67.9 vs 81.7% predicted). Chronic sputum production and its negative relationship with best function was strongly associated with smoking. There was little relationship between chronic sputum and persistent obstruction in nonsmokers. There were no univariate associations between sputum during attacks, or its color, and pulmonary function, but after allowing for demographic factors, including smoking, green sputum was associated with persistent obstruction. There was little relationship between sputum and actual/best function at attendance. CONCLUSIONS: Chronic sputum production is associated with persistent obstruction principally in those who have smoked, suggesting that the association reflects smoking rather than asthma. There is no interaction with atopy. After allowance for cigarette smoking, there is an association between green sputum production during exacerbations and persistent obstruction. Green sputum during relapse in asthma may indicate inflammation that is relevant to prognosis.

Adult↗

PubMed1994

Actual over best function as an outcome measure in asthma.

Several guidelines for the management of asthma suggest that actual/best function is a useful outcome measure. This implies accurate assessment of best function, and a standard for the proportion of best function to be achieved. Seventeen clinics observed their practice simultaneously during four periods in 1990. The aims of the study included testing a protocol for the assessment of best function, and validating actual/best function as an outcome measure. The proposed target for actual/best function to indicate satisfactory control was 80%. The protocol for assessment of best function required formal trial of steroids if best function was < 70% predicted; with regular recording of peak expiratory flow (PEF) if < 80% predicted. PEF was recorded in 515 and FEV1 in 680 of 767 subjects, following the usual clinic practice. If the protocol for best function was not satisfied, mean actual/best function was no higher than if it was, except when best PEF was < 70% predicted. This suggests the need for a PEF chart in these latter patients. Best function was greater in females than males, but actual/best function was almost identical. Whilst best function declined with increasing intensity of treatment, actual/best function was almost independent of regimen step, particularly in the centre which most closely adhered to the protocol. These results confirm that actual/best function is a valid outcome measure. Mean actual/best was > 80% except for FEV1 in two centres. It is suggested that the target in chronic management of asthma is raised from 80 to 85% of best, when actual/best PEF is used as a spot check in patients believed to be on optimal therapy.

Asthma↗

PubMed1992

Steroid-induced bone disease. Conflicting views of respiratory and bone physicians.

Physician members of the Thoracic Society and the Bone and Tooth Society were circularised about their views on the prophylaxis, screening and treatment for steroid osteoporosis. Bone physicians were more active than respiratory physicians in screening and prophylaxis and were more likely to favour bone densitometry in assessment and bisphosphonates in treatment. Further studies are required to establish the value of prophylactic agents in steroid osteoporosis but meanwhile respiratory physicians should appreciate the value of the relatively simple technique of bone densitometry in assessment and consider whether they should be more active in prophylaxis.

Adult↗