Asthma Research Unit - Research Poster

Asthma Research Unit Posters

Identifying Patients "At Risk" of
an Exacerbation of Asthma

Presented at the
European Respiratory Society Conference
September 1998, in Geneva

G Hoskins, C McCowan, G E Thomas,
R G Neville, B Smith, S Silverman

Aim

To determine whether there were any factors that could assist in the identification of patients with asthma who were ‘at risk’ of an exacerbation and possible asthma attack.

Method

Two studies which involved the audit of asthma management within a general practice setting. 393 practices from throughout the United Kingdom provided details of health service resource use for 30 randomly selected asthma patients over a retrospective 12 month period. This provided a data set on the management of 12,203 patients with asthma, stratified by age. All patients were invited for a clinical assessment. The database was utilised to extract and evaluate the risk factors contributing to an asthma attack. Risk factor analysis could only be carried out on the 9,625 patients who attended for review. Logistic multiple regression was used to model the chance of occurrence of an asthma attack in terms of a set of categorised predictor variables.

Results

Figures represent % for each category

Healthcare
contact & attack rate
n=12,203

Age Group (years)

0-4
n=597
(5%)

5-15
n=3362
(28%)

16-44
n=4315
(35%)

45-74
n=3446
(28%)

75+
n=483
(4%)

Asthma attack

37

21

19

23

27

Admission

13

2

2

3

5

A&E contact

11

3

3

2

2

OPD contact

16

5

3

9

7

Consultation
81

63

52

59

60

Review

75

72

59

70

67

% of patients who attended for Study Review

Age Group (years)

Symptom/
Risk Factor
n=9,625

0-4
n=469
(5%)

5-15
n=2742
(28%)

16-44
n=3052
(32%)

45-74
n=2950
(31%)

75+
n=412
(4%)

Symptoms: Night
45

27

36*

38*

40

Morning
36

29

44

52

60

Exercise
41

50*

55*

67

83

Poor: Compliance
14

15

19

13

12

Poor:Inhaler tech.
12

7

8*

9

14

* found to be a significant (p<0.01) factor for attack occurrence

In the 5-15 age range exercise symptoms were significant

In the 16-44 age range night symptoms, exercise symptoms and poor inhaler technique were significant

In the 45-74 age range night time symptoms were significant

Conclusion

There are many unknown factors which contribute to a patients risk of an asthma attack. In the under 5s there were no significant markers to identify those at risk but this group had the greatest incidence of attack (37%). The presence of night and exercise symptoms were important attack markers across a wide range of ages. Although statistically small, these appear to be the best symptom markers for the likelihood of an attack. Level of British Asthma Guideline (BAG) treatment step was also found to be a statistically significant factor in all but the under 5s. The percentage at risk of an attack became greater as the BAG step increased from 1 to 5. More work linking treatment strategies to patient outcome data could be of value in further understanding how BAG positioning relates to asthma control. In clinical practice detailed knowledge of risk factors associated with different age categories could help in prioritising management of poorly controlled patients.

This study was financed by a grant from Zeneca Pharmaceuticals

For further information on the Asthma Research Unit, please contact:
Tayside Centre for General Practice
University of Dundee
Kirsty Semple Way
Dundee DD2 4BF
Scotland
Tel : +44 (0)1382 420000
Fax :+44 (0)1382 420010
aru@tcgp.dundee.ac.uk

Updated by Mark Stewart: Tuesday, November 6, 2001