Page 26 - ADULT-ONSET ASTHMA PREDICTORS OF CLINICAL COURSE AND SEVERITY

ADULT-ONSET ASTHMA – PREDICTORS OF CLINICAL COURSE AND SEVERITY
FACTORS DETERMINING DECLINE IN LUNG FUNCTION IN ADULT ASTHMA
Pa ents with asthma have a faster decline in lung func on compared to healthy controls 28, 29, but an even greater lung func on decline is seen with a later age of disease onset 30-32. Late- onset asthma also increases the risk of persistent air ow limita on 21, 33. However, li le is known about factors in uencing lung func on of adult-onset asthma pa ents and only a few longitudinal studies are available.
PREDICTORS OF LUNG FUNCTION DECLINE IN ADULT-ONSET ASTHMA
In adults with asthma di erent clinical and in ammatory factors in uence the decline in lung
func on. Ulrik et al. showed a di erence in annual FEV1 decline between non-atopic and atopic
asthma, respec vely 50 ml/y vs 22,5 ml/y (p<0.0001) 34. Whereas Cibella et al,. did not nd
an e ect of atopy on FEV1 decline 35. However, they did nd a steeper FEV1 decline in young
(≤43y) asthma cs with a baseline FEV1<80% predicted. In a longitudinal analysis of a Korean
asthma cohort, Park et al., found no FEV1 decline a er 12 months in a cluster with late-onset
asthma. However, this cluster was predominantly female (72,6%) and had mild asthma with an
FEV ofalmost100%predictedatbaseline36.Sakagamietal.characterizedinaclusteranalysis 1
2 out of 3 clusters as late-onset asthma 37. One cluster was male dominated, with low FEV1/ FVC at diagnosis and with the highest serum total IgE, but a low incidence of atopy. This group had a more accelerated FEV1 decline compared to the other clusters. Amelink et al. found similar results in a cross-sec onal study, where non-atopic males with adult-onset asthma had more o en persistent air ow limita on and might be at risk for accelerated lung func on decline 22. Another study reported an accelerated FEV1 decline in a subgroup with persistent air ow limita on which was correlated to baseline sputum eosinophils (r = 0.53, P <0.05) and frac on of nitric oxide in exhaled air (FeNO)(r = 0.55, P <0.05) 38. A 5 year follow up study in di cult-to-treat asthma pa ents con rmed the la er nding in pa ents with a baseline FEV1 ≥80%; FeNO ≥20 ppb was predic ve for excess lung func on decline (RR of 3.1 (95% CI, 1.7–3.4)) 39. For persistent air ow limita on sputum eosinophilia (≥2%) was also reported as an independent risk factor with an odds ra o (OR) of 8.9 (95% 1.3–59.0) 21. S ll, the role of eosinophilic in amma on as predictor of lung func on decline is not en rely established as in ammatory pro les might change over me40-42. In a study with 97 severe asthma pa ents Newby et al., reported high uctua on in eosinophil percentage as a dependent factor for postbronchodilator FEV1 decline 43. Furthermore, infec on with Chlamydia pneumonia in non-atopic adult-onset asthma pa ents was strongly associated to a decreased FEV1/FVC-ra o related to asthma dura on as compared to atopic pa ents 44. And nally, a large longitudinal popula on study found in pa ents with asthma onset ≥ 25 years, male gender and pack years to be the strongest risk factors of persistent air ow limita on (per 10 pack year a risk ra o (RR) 1.4 95% CI 1.2-1.7) 33. Similar results were reported in a cross-sec onal study with 1017 severe or di cult-to-treat asthma pa ents. The authors found an associa on between
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