Editorials

The Seduction of Asthma Severity Categorization

Most primary medical conditions cause a wide spectrum of complications and sequelae, which may compromise physiologic and psychological function. Comprehensive, integrated care based on key principles includes individualized plan, multidisciplinary teamwork, and recognition of all the elements of the disease. The primary goal is to help the individual with a chronic medical condition enhance the exercise capacity, functional status, and quality of life. For the most part, treatment relies heavily on well assessment and aims to address clinical performance by physiotherapy, exercise training, education, and psychosocial intervention.

To identify variables patients use to determine the severity of their asthma, the perceived severity (PS), using a fuzzy decision-making analysis (FDMA). To compare these variables with those involved in the assessment of asthma severity according to the global initiative for asthma (GINA) guidelines, the objective severity (OS).

Outpatients (51 men, 62 women), aged (m±SD) 42.9±16.3 years with (% patients) mild intermittent (6.2), mild persistent (15.9), moderate (65.5) and severe (12.4) asthma.

Cross sectional, observational study.

Both OS (rated by doctors) and PS (rated by patients) were rated as mild intermittent, mild persistent, moderate, or severe. Variables involved in OS assessment, variables self-assessed by patients (dyspnea, perceived treatment efficacy, asthma-related quality of life questionnaire [AQLQ]), patients’ sociodemographic characteristics, and asthma characteristics, were evaluated with questionnaires. These variables were pooled, and considered as potential variables patients might use to determine their PS. They were tested against the PS measurement using FDMA. This identified variables patients actually used to determine PS.

On the day of consultation, 68.1% of patients classed their asthma as mild intermittent or mild persistent, 23.9% as moderate persistent, and 8.0% as severe persistent. There was a significant discrepancy (p<0.01) between PS and OS with a clear patient tendency to underestimate asthma severity as compared to OS. Patients determined PS level according to variables assessing their asthma perception, i.e., AQLQ measures and dyspnea, but not variables involved in OS assessment, such as symptom frequency or knowledge of their peak flow rates. Duration of asthma and treatment characteristics were also involved.

FDMA identified variables patients used to determine PS. It highlighted a discrepancy between patients’ and doctors’ perceptions of asthma severity, suggesting that assessment of asthma severity should consider both patients’ and doctors’ perceptions of the disease and includes an AQLQ measure.

The evolution of asthma starting in childhood varies and depends on a series of factors (atopy, allergens, and environmental irritants, etc). Treatment may influence the evolution of the disease and even cause the symptoms to disappear. However, there remains a risk of relapse years later.

To assess the role of bronchial hyperresponsiveness in asthma relapse in young adulthood in patients with symptoms that disappeared after treatment prescribed in childhood.

To determine the evolution of asthma and patients’ personal opinions, 78 patients were sent a questionnaire several years after having been discharged without symptoms in the previous 2 years, and without the need for medication. The methacholine test was used to evaluate bronchial hyperresponsiveness at discharge. The 40 patients who correctly completed the questionnaire were divided into three groups according to the methacholine dose required to obtain a 20 % decrease in forced expiratory volume in 1 second (PD20): group 1 (15 patients), < 1000 μg; group 2 (10 patients) between 1001 and 2000 μg; and group 3 (15 patients) > 2100 μg. The mean age at discharge was 16 years (range 13-25 years) versus 26 years at the time of response (range 18-33 years), with a similar distribution in all three groups. Age at disease onset, with estimation of severity, age at the first visit and at the start of treatment, and respiratory function were evaluated.

Thirty of the interviewed patients considered themselves to be cured. Seven of the patients (three in group 1, one in group 2, and three in group 3) did not consider themselves to be cured, although their symptoms were minimal and they rarely used medication. Health status was described as “regular” with sporadic symptoms by one patient in each group. No correlation with methacholine response was observed.

No relationship was found between the degree of bronchial hyperresponsiveness and the risk of relapse in young adults who suffered asthma in childhood.

The natural history of asthma severity is poorly known.

To investigate prognostic factors of asthma severity.

All current patients with asthma identified in 1991 to 1993 in the European Community Respiratory Health Survey were followed up, and their severity was assessed in 2002 by using the Global Initiative for Asthma categorization (n = 856). Asthma severity (remittent, intermittent, mild, moderate, severe) was related to potential determinants evaluated at baseline and during the follow-up by a multinomial logistic model, using the intermittent group as the reference category for relative risk ratios (RRRs).

Asthma severity measured at baseline was a determinant of a patient's severity at the end of the follow-up. At baseline, severe persistent had a poorer FEV₁% predicted, a poorer symptom control, higher IgE levels (RRR, 2.06; 95% CI, 1.38-3.06), and a higher prevalence of chronic cough/mucus hypersecretion (RRR, 4.90; 95% CI, 2.18-11.02) than patients with intermittent asthma. Moderate persistent showed the same prognostic factors as severe persistent, even if the associations were weaker. Mild persistent had a distribution of prognostic factors that was similar to patients with intermittent asthma, although the former showed a poorer symptom control than the latter. Remission mainly occurred in patients with less severe asthma and was negatively associated with a change in body mass index (RRR, 0.86; 95% CI, 0.75-0.97). Allergic rhinitis, smoking, and respiratory infections in childhood were not associated with asthma severity.

Patients with moderate and severe persistent asthma are characterized by early deterioration of lung function. High IgE levels and persistent cough/mucus hypersecretion are strong markers of moderate/severe asthma, which seems to be a different phenotype from mild persistent or intermittent asthma.

Our results suggest that the evolution of asthma severity is to a large extent predictable.

To provide a conceptual framework for defining severity and control in asthma, to describe recent advances in measuring asthma control, and to discuss the role of severity and control in asthma disease management.

MEDLINE was searched for relevant English-language articles published between 1998 and July 2003. Additional sources included key references cited in these articles, national and international guidelines for the diagnosis and management of asthma, and the author's personal bibliography.

All studies that reported on the development and validation of formal measures of asthma control, as well as the few editorials that focused on the distinction between asthma severity and control, were included. The author's professional judgment was used to select for illustrative purposes from among the many purported measures of asthma severity in the literature.

Although several standardized measures of asthma control exist, no direct comparisons of the performance and properties of these control measures have been published. The available instruments appear more similar than dissimilar. All share the common trait of assessing multiple aspects of asthma control, which is believed to provide better discrimination than a single measure.

Asthma control is different from asthma severity and may be useful as a clinical vital sign for patients with asthma. Ultimately, no one measure may be better than any of the others or the optimal measure may depend on the intended use of the scale.

A very weak relationship has been reported between the health-related quality of life (HRQL) of patients with asthma and their degree of airway hyper-responsiveness (AHR), evaluated in terms of sensitivity. However, this relationship still has not been sufficiently explored for bronchial reactivity indices.

To analyse the relationship between bronchial reactivity and sensitivity with the HRQL of patients with stable asthma, identifying the functional parameters that determine HRQL.

In 103 consecutive patients with stable asthma, HRQL was evaluated using the Asthma Quality of Life Questionnaire (AQLQ). Patients underwent spirometry and non-specific bronchial provocation with methacoline. Sensitivity (PD₂₀) and reactivity (dose-response slope (DRS), continuous index of responsiveness (CIR) and bronchial reactivity index (BRI)) of the dose-response curve were analysed.

BRI presented significant differences with different degrees of asthma severity. Although patients with AHR showed poorer quality of life than patients without AHR, the AQLQ total score was not related to PD₂₀ but rather to DRS (r=−0.784), CIR (r=−0.712) and BRI (r=−0.776). The indices of bronchial reactivity reached a negative correlation with all the domains of the AQLQ. In a multiple linear regression model, BRI, DRS, FIV₁ (forced inspiratory volume in 1 s) and VCIN (inspiratory vital capacity) were identified as independent predictors of the AQLQ total score (r²=0.742, p<0.001).

In patients with stable asthma, bronchial reactivity is associated with HRQL. This could justify incorporating bronchial reactivity indices in bronchial provocation analyses.