Assessing future need for acute care in adult asthmatics: the Profile of Asthma Risk Study: a prospective health maintenance organization-based study.
OBJECTIVE
To develop simple clinical tools predictive of acute asthma care and to identify modifiable risk factors.


METHODS
Prospective cohort study.


METHODS
A large health maintenance organization (430,000 members).


METHODS
Adult members (18 to 55 years old) with asthma.


METHODS
Data from a questionnaire, skin-prick testing for inhalant allergens, and spirometry were collected at the baseline visit. Acute care utilization data were obtained from administrative databases for a subsequent 30-month period.


METHODS
This two-phase study first identified and performed a split-sample validation on three clinical tools to determine their predictive ability by employing data from a questionnaire, questionnaire plus spirometry, and questionnaire plus spirometry and skin-prick testing. Second, it identified modifiable independent risk factors.


RESULTS
The 554 study participants generated 173 episodes of acute care over 1,258 person-years of follow-up (0.14 episodes per person per year). Of these, 101 participants had at least one episode, and one third of this group had two or more episodes. Clinical scoring into risk groups was done by reverse stepwise regression analyses. Using relative risks (RRs) as a guide, high-risk, moderate-risk, and low-risk groups were identified. The high-risk groups, 13 to 21% of the validation sample, had a 7- to 11-fold increased risk for hospital care compared to the low-risk groups. The moderate-risk groups, 46 to 50% of the validation sample, had a twofold- to fourfold-increased risk. FEV(1) was the most significant predictor (RR, 4.33). Of the four potentially modifiable risk factors identified, current cigarette smoke exposure (RR, 1.6) and ownership and skin-prick test positivity to cat or dog (RR, 1.5) were the most significant.


CONCLUSIONS
These models stratify asthma patients at risk for acute care. Patients with lower FEV(1) values are at significantly higher risk, underscoring the importance of spirometry in asthma care.
Osborne
Molly L
ML
Mail code L102, Oregon Health and Science University, 3181 SW Sam Jackson Park Rd, Portland, OR 97239, USA. osbornem@ohsu.edu
Pedula
Kathryn L
KL
O'Hollaren
Mark
M
Ettinger
Kenneth M
KM
Stibolt
Thomas
T
Buist
A Sonia
AS
Vollmer
William M
WM
D000208:Acute Disease; D000328:Adult; D001249:Asthma / Q000453:epidemiology* / Q000503:physiopathology; D005260:Female; D005541:Forced Expiratory Volume; D006279:Health Maintenance Organizations; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D018570:Risk Assessment; D013147:Spirometry; D011795:Surveys and Questionnaires