Proportion of asthmatics with lung eosinophilia
Study | Case definition* | Method | Definition of eosinophilic and non-eosinophilic asthma based on cut off values** | No | Eosinophilic asthma |
---|---|---|---|---|---|
*All asthma cases were recruited from symptomatic patients attending a clinic, unless indicated otherwise; these studies therefore only give a crude estimate of the proportion of asthma which is characterised by lung eosinophilia in selected populations. | |||||
†Induced and spontaneous sputum. | |||||
‡Children with asthma symptoms not recruited through a clinic. | |||||
§Children with bronchial hyperresponsiveness (BHR). | |||||
¶In case the authors did not define a cut off or when a cut off of less than 2% was chosen in the original study, we have set the cut off at 2%. | |||||
**Cut off was determined based on eosinophil counts in control subjects unless indicated otherwise. | |||||
††30 obstructed ICS treated patients were included in the study but in the figure only 26 could be observed. Individual sputum data for the other three asthma groups (ICS treated non-obstructed and ICS naïve obstructed and non-obstructed patients) were not given in the article. | |||||
‡‡59 patients were included in the study but in the figure only 56 could be observed. | |||||
Studies in adults: | |||||
Fahy et al (1995)32 | Acute severe asthma | Sputum | 2% eosinophils¶ | 18 | 50% |
Turner et al (1995)24 | Mild asthma with exacerbation in past 2 weeks | Sputum† | 4% eosinophils¶ | 34 | 47% |
Pizzichini et al (1996)27 | Stable asthma | Sputum | 2% eosinophils¶ | 19 | 58% |
Wenzel et al (1999)18 | Severe asthma, corticosteroid (CS) dependent | Bronchial biopsy | Mean eosinophil count +2SD (exact value not given) | 34 | 59% |
Pavord et al (1999)22 | Asthma patients treated with β2 agonists | Sputum | 3% eosinophils¶ | 23 | 61% |
Pavord et al (1999)33 | Asthma of variable severity | Sputum† | 3% eosinophils | 26 | 88% |
Jatakanon et al (1999)23 | Persistent asthma of variable severity: | Sputum | 2% eosinophils | 55 | 60% |
• Mild persistent | 23 | 78% | |||
• Moderate persistent | 16 | 38% | |||
• Severe persistent | 16 | 56% | |||
Lemiére et al (1999)34 | Asthma of variable severity | Sputum | 2% eosinophils | 6 | 33% |
Berlyne et al (1999)30 | Asthma of variable severity | Sputum† | 2% eosinophils | 84 | 52% |
Mean eosinophil count + 2SD (87 × 103/g) | 84 | 82% | |||
Tarodo de la Fuente et al (1999)35 | Asthma of variable severity | Sputum | 2% eosinophils | 38 | 34% |
• Mild untreated | 9 | 22% | |||
• Moderate treated with ICS | 12 | 25% | |||
• Severe CS dependent | 17 | 47% | |||
Ordoñez et al (2000)36 | Acute severe asthma | Tracheal aspirates during intubation | 2% eosinophils¶ | 10 | 70% |
Wark et al (2000)37 | Asthma of variable severity: | Sputum | 2.75% eosinophils | 32 | 44% |
• Not treated with ICS | 15 | 67% | |||
• Treated with ICS | 17 | 24% | |||
Giannini et al (2000)38 | Stable asthma treated with CS, currently asymptomatic | Sputum | 3.0% eosinophils | 30 | 33% |
Gibson et al (2001)21 | Persistent asthma, BHR, CS dependent: | Sputum | 2.5% eosinophils | 56 | 41% |
• Mild persistent | 11 | 27% | |||
• Moderate persistent | 26 | 46% | |||
• Severe persistent | 19 | 42% | |||
Ottanelli et al (2001)39 | Stable persistent asthma treated with ICS with FEV1/FVC <70% | Sputum | 2.0% eosinophils | 26†† | 62% |
Fahy et al (2001)40 | Moderate to severe asthma | Sputum | 2.0% eosinophils | 56‡‡ | 59% |
Studies in children: | |||||
Gibson et al (1998)20 | Open population incl non-symptomatic subjects: | Sputum | 2.5% eosinophils¶ | (162) | (27%) |
• Symptoms in past 2 weeks‡ | 56 | 41% | |||
• BHR§ | 23 | 62% | |||
Gibson et al (1999)41 | Acute severe asthma | Sputum | 2.5% eosinophils | 37 | 88% |
Marguet et al (1999)19 | • Asthma with recurrent symptoms | BAL | 2% eosinophils¶ | 14 | 57% |
• Infantile wheezers (age 5–46 months) | 26 | 19% | |||
Wilson et al (2000)31 | Asthma of variable severity: | Sputum | 2% eosinophils¶ | 36 | 19% |
• Not treated with ICS | 21 | 29% | |||
• Treated with ICS | 15 | 7% | |||
Gibson et al (2001)42 | Asthma defined as wheezing in last 12 months‡ | Sputum | 2.5% eosinophils | 22 | 45% |