PURPOSE: It was recognized that treatments could improve clinical symptoms and lung functions, but it is still controversial whether treatments can reduce the airway wall thickness and change the pulmonary density. The review is to confirm the effects of treatments on the morphological abnormalities of the airway and parenchyma in asthma using HRCT.
METHODS: We systematically searched five databases for relevant studies and abstracted the data. HRCT findings were pooled as the effects of treatment in both random and fixed effects models for RCTs and case-control studies. Heterogeneity was assessed with Chi-squared test, and publication bias was examined with Funnel plots.
RESULTS: Among the seven eligible papers including two RCTs and five case-control studies, six trials used various inhaled corticosteroids for asthmatics (dosage: 200g-1600g/d, duration: 4 weeks-16.8 months), and one trial chose montelukast to treat asthmatics (10mg/d, 4 weeks). There was a significant difference in MLD, BWI, air trapping, and centrilobular prominence between posttreatment and pretreatment in asthmatics. MLD after treatment increased 9.72 (HU),BWI diminished 0.07, air trapping decreased 0.41 scores, centrilobular prominence reduced 0.67 grades, and LAA declined 7.30%. These alterations were consistent with the changes in FEV1, FEV1 %, PEF and PC20. However, the pooled results produced a negative conclusion in WA, WA% and BD. Compared with the controls, the posttreatment asthmatics had still lower MLD, higher BMI, more grades of centrilobular prominence, more prevalent air trapping and greater LAA. These changes of HRCT findings were coincident with the changes in FEV1, FEV1 %, PEF and PC20. Nevertheless, there were no differences of WA, WA% and BD between the posttreatment asthmatics and the controls.
CONCLUSION: Treatments could partly ameliorate the morphological abnormalities of airway and parenchyma in asthmatics, and the alterations were associated with improved lung functions and elevated PC20. However, treatments could not completely make the worse morphological abnormalities in asthmatics normalization.
CLINICAL IMPLICATIONS: This should be stressed that long-term and more studies evaluating airway remodeling by HRCT may confirm whether early treatment prevents airway remodeling in asthmatics.
DISCLOSURE: Shiman Wu, None.