Background . Various clinical and objective measures are currently used to assess severity of acute asthma; however only a few studies have been done to determine whether these variables include separate or distinct dimensionsAim : To find most important variables and distinct dimensions of acute asthma severity by exploratory factor analysis.
Retrospectively obtained data from 94 patients with acute asthma (mean age = 37.3 +/− 16.2 years) including variables like age, Body Mass Index (BMI), duration of attack, heart rate, respiratory rate (RR), Oxygen satuaration (SpO2 %) peak expiratory flow (PEF), FEV1 percent of predicted, Borg Dyspnoea Score (BDS), steroid use, pulsus paradoxus (PP) and early response to treatment in were analyzed by Principal Axis Factor analysis and the Factors extracted with this method were then rotated orthogonally through the Varimax procedure.
Only three factors had Eigen value greater than 1 and were included as separate dimensions .The first factor contained PEF and FEV1 percent of predicted and early response of treatment (measured by the percent variation of FEV1 at 30 min over baseline. Factor 2 contained RR, SpO2 %, and BDS. Factor 3 contained heart rate, steroid use and BMI. Eigen values of factors 1, 2, 3 were 4.90, 2.02, 1.43 and variance accounted for was 40.8 %, 15.1 % and 11% respectively. PP did not figure in any of these factors.
Early response to treatment and BMI in combination with measures of the three identified factors could be included in other acute asthma protocols. Most of the subjective and objective measures (except PP) utilized in the assessment acute asthma have non-overlapping dimensions with pulmonary function and early response being most important variables.
Factor analysis would help to create better standard questionnaires for evaluation of acute asthma.
Arvind Kumar, No Financial Disclosure Information; No Product/Research Disclosure Information