Predictors of asthma severity in the elderly: Results of a community survey in northeast England

A number of risk factors for the development and severity of asthma in chil dhood are known. Particularly, there is information on allergens, excessive use of beta(2)-agonists, and indoor environmental pollutants. Similar info rmation on elderly patients is lacking. We examined the risk factors for cu rrent asthma and for the severity of asthma in 95 elderly subjects (>65 yea rs old) compared to 274 elderly subjects with obstructive spirometry who di d not have asthma as defined by the following criteria: symptoms of episodi c wheeze, cough, or chest tightness and forced expiratory volume in 1 sec/v ital capacity (FEV1/VC) <70% with >15% or 200 mL reversibility in FEV, to 2 00 mu g salbutamol given from a metered-dose inhaler. The severity of airfl ow limitation was graded on the basis of the FEV1/VC ratio as mild (60%-70% ), moderate (40%-60%), and severe (<40%). Asthma history was collected usin g the Medical Research Council respiratory questionnaire and a follow-up po stal questionnaire. Data were analyzed using multiple logistic regression a nd the overall goodness-of-fit of the model was checked using the Hosmer-Le meshow (HL) statistic. History of allergy (to one or more of the following allergens: cat, house dust, or grass or tree pollen) (odds ratio [OR] 25; 9 5% confidence interval [CI] 13-51; p = 0.0001) and history of childhood whe eze (OR 8; 95% CI 4-9; p = 0.004) were strong predictors of current asthma. Duration of wheezing, smoking history, indoor heating, history of working in coal mines, and sex were not predictors (HL 6.75, degrees of freedom [df ] = 8, p = 0.56). Use of >4 puffs of salbutamol/ day (OR 5.3; 95% CI 2-14; p = 0.005), more than 10 years of asthma symptoms (OR 4.2; 95% CI 4.1-36.2; p = 0.0001), and >500 mL reversibility in FCV1 (OR 4.2; 95% CI 1.2-14.3; p = 0.05) were independent predictors of moderate to severe asthma. History of atopy was the strongest predictor of asthma in the elderly population st udied. Indoor heating, presence of pets at home, sex, smoking history, and history of working in coal mines were not predictors of asthma. The severit y of asthma as assessed by measurement of airflow limitation was related to the frequency of use of beta(2) -agonists, duration of symptoms of asthma, and increased reversibility of FEV1 to beta(2)-agonist.