A nebulizer is preferable to a metered-dose inhaler (MDI) with spacer for delivering salbutamol in patients with chronic obstructive pulmonary disease (COPD) younger than 65 years and in those with severe spirometric abnormalities, investigators reported in Therapeutic Advances in Respiratory Disease.
The investigators conducted a retrospective study to assess the how salbutamol administered by an MDI with spacer vs a nebulizer affected bronchodilator responsiveness testing in patients with COPD.
Patient data were obtained from a hospital in China from December 1, 2021, to June 30, 2022. Participants were adults (aged ≥18 years) with spirometry-defined COPD and relevant symptoms and a forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC) postbronchodilator ratio of less than 0.70.
The predicted and test values for FEV1 and FVC pre- and post-bronchodilator administration were recorded. The primary outcome was the effect of salbutamol with a nebulizer or an MDI with spacer on absolute change, percentage change from baseline, and change relative to the predicted value. A significant BDR response was an absolute increase of more than 200 mL and a relative increase of more than 12% in FEV1 and/or FVC from baseline.
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In the context of BDR testing, it might be more suitable for adult patients under 65 years of age with significantly impaired baseline lung function to receive bronchodilators through nebulization.
The study included 894 patients (median age, 63 years; 83.2% male), of whom 578 received bronchodilators through an MDI with spacer, and 316 received them with nebulization. After propensity score matching, 240 pairs of patients were enrolled.
In the matched cohorts, changes in FEV1 and FVC, FEV1% and FVC%, and FVC percent predicted were comparable in the 2 delivery techniques. For younger patients (<65 years), the increment in FEV1 from pre- to post-bronchodilator administration in the nebulization group was greater compared with the MDI group (0.11 vs 0.08 L). The nebulization group had an overall significantly higher change in FEV1 percent predicted compared with the MDI group (3.44% vs 2.97%), particularly in younger patients (3.85% vs 3.02%).
Patients who used nebulization had a 30-mL greater increase in change in FEV1 and a 1.09% higher increase in change in FEV1 percent predicted from baseline vs MDI with spacer after controlling for confounders.
An increased BDR response rate — based on the criterion of change in FEV1 and/or change in FVC more than 12% and less than 200-mL vs the criterion of change in FEV1 percent predicted or change in FVC percent predicted greater than 10% — occurred among the different subgroups.
For patients aged younger than 65 years, the positive rate of BDR was 1.65 times greater than that in those aged 65 years or older, according to absolute and percentage change in FEV1 or FVC (odds ratio [OR], 1.65; 95% CI, 1.10-2.46). Among patients who had severe lung function impairment, the significant BDR rate was 0.52 times vs that in those who had very severe lung function impairment (OR, 0.52; 95% CI, 0.35-0.79). The significant BDR rate with a nebulizer was 1.67 times greater compared with an MDI with spacer (OR, 1.67; 95% CI, 1.13-2.47) in multivariate logistic regression.
Study limitations include the retrospective design and the omission of half of the population in order to adjust for confounders. Also, only patients with moderate-to-very severe lung function impairment based on FEV1 percent predicted were included and they were not differentiated between stable and exacerbation status. Additionally, patients with other airway limitations were not included.
“In the context of BDR testing, it might be more suitable for adult patients under 65 years of age with significantly impaired baseline lung function to receive bronchodilators through nebulization,” the study authors stated.
