Pulmonology · Medical Literature
[Clinical characteristics of smoking asthma and efficacy of long-acting muscarinic antagonist in treating patients with smoking asthma].
Abstract
Objective: To analyze the clinical characteristics of smoking asthmatic patients and to evaluate the efficacy of long-acting muscarinic antagonist (LAMA) in treating smoking asthmatic patients. Methods: The characteristic analysis study of smoking asthma was a case-control study, including 128 patients with bronchial asthma. According to whether the patients smoked, they were divided into the smoking asthma group and the non-smoking asthma group. The clinical data, blood indicators, lung function indicators [forced expiratory volume in one second (FEV1), FEV1/forced vital capacity (FEV1/FVC), maximum mid-expiratory flow (MMEF 75/25)], and fractional exhaled nitric oxide (FeNO) were compared between the two groups. The efficacy of LAMA in treating smoking asthma patients was a randomized controlled trial. A total of 60 male patients with moderate to severe asthma, who were smokers and in a non-acute attack phase, were screened. According to computer-generated random numbers, they were divided into the intervention group [administered inhaled corticosteroid (ICS)+long-acting beta agonist (LABA)+LAMA for 1 month] and the control group (administered ICS+LABA for 1 month) in a 1∶1 ratio. Clinical characteristics, blood indicators, lung function indicators, asthma control test (ACT) scores, and Asthma Quality of Life Questionnaire (AQLQ) scores were collected before and after 1 month of treatment, and efficacy indicators were compared within and between groups before and after treatment. Results: A total of 98 patients were included in the non-smoking asthma group, aged (61.9±14.3) years, and 30 were male. A total of 30 patients were included in the smoking asthma group, aged (60.4±15.2) years, all of whom were male. The proportion of males in the smoking asthma group [30.0 (100.0)% vs 30.0 (30.6)%], blood neutrophil count [(4.5±1.9)×109/L vs (3.3±2.0)×109/L], and blood neutrophil ratio [(64.0±16.5)% vs (51.2±23.2)%] were higher than those in the non-smoking asthma group (all P 0.05). The number of cigarettes smoked in both groups decreased before and after treatment [intervention group: (20.3±8.0) cigarettes/d vs (8.7±6.2) cigarettes/d; control group: (20.5±7.6) cigarettes/d vs (8.3±5.3) cigarettes/d], but there was no significant difference between the two groups before and after treatment (all P>0.05). Intra-group comparison, FEV1, FVC, FEV1/FVC, MMEF 75/25, ACT score, and AQLQ score of intervention group after treatment were higher than those before treatment, and FeNO of intervention group after treatment was lower than before treatment (all P<0.05). After treatment, the ACT score and AQLQ score of control group were higher than those before treatment (all P<0.05). Between-group comparison showed that after treatment, the intervention group had higher FEV1 [(2.5±0.7) L vs (1.9±0.7) L], FVC [(3.2±0.9) L vs (2.7±0.9) L], FEV1/FVC [(78.6±6.7)% vs (72.8±11.7)%], ACT score [23.0 (23.0, 24.0) points vs 21.5 (20.3, 24.0) points], and AQLQ score [101.0 (98.0, 104.0) points vs 97.5 (93.0, 101.3) points], and lower FeNO [14.5 (10.0, 28.3) ppb vs 25.0 (19.3, 51.5) ppb] than the control group (all P<0.05). Conclusions: This study indicates that smoking asthmatic patients have worse pulmonary function but lower FeNO and peripheral blood eosinophil counts than non-smoking asthmatic patients. Compared to ICS+LABA alone, the addition of LAMA to ICS+LABA significantly improves pulmonary function, reduces FeNO, and enhances symptom control and quality of life in smoking asthmatic patients.
Clinical relevance
In patients with smoking asthma, what are the distinguishing clinical characteristics compared with non-smoking asthma patients, and does the addition of a long-acting muscarinic antagonist (LAMA) to ICS/LABA improve outcomes compared with ICS/LABA alone in moderate-to-severe smoking asthma? __SNAPSHOT__ {"studyDesign":"Two-part study: (1) Case-control study (clinical characteristics analysis); (2) Randomized controlled trial (LAMA efficacy evaluation)","setting":"Not reported; study published in a Chinese medical journal (Zhonghua yi xue za zhi), likely conducted in China","sampleSize":"Case-control: n=128 patients with bronchial asthma (smoking vs. non-smoking subgroups, exact n per group not reported in available abstract). RCT: n=60 male patients with moderate-to-severe asthma (intervention group: ICS+LABA+LAMA; control group: ICS+LABA; allocation ratio 1:1 per computer-generated randomization, exact per-group n not reported in available abstract)","population":"Case-control: adults with confirmed bronchial asthma, stratified by current smoking status. RCT: male patients with moderate-to-severe asthma who were current smokers and in a non-acute attack phase","intervention":"RCT intervention group: inhaled corticosteroid (ICS) + long-acting beta-2 agonist (LABA) + long-acting muscarinic antagonist (LAMA) for 1 month","comparator":"RCT control group: ICS + LABA for 1 month (standard dual therapy)","primaryOutcome":"Case-control: clinical data, blood indicators, lung function parameters (FEV1, FEV1/FVC, MMEF 75/25), and fractional exhaled nitric oxide (FeNO). RCT primary outcome(s): not fully reported in the available abstract excerpt","followUp":"RCT treatment duration: 1 month. Longer follow-up: not reported","fundingSource":"Not reported"}
Key findings
The available abstract is incomplete — it is truncated before reporting the results of either the case-control or the RCT component. Therefore, no primary outcome data, effect sizes, confidence intervals, p-values, or adverse event frequencies can be summarized from the provided text. The case-control component compared smoking versus non-smoking asthma patients across clinical characteristics, blood biomarkers, spirometric parameters (FEV1, FEV1/FVC, MMEF 75/25), and FeNO, but the direction and magnitude of differences are not reported in the available excerpt. The RCT component randomized 60 male smokers with moderate-to-severe asthma in a non-acute phase to 1 month of ICS+LABA+LAMA versus ICS+LABA, but no outcome results are available from the provided text. No NNT, NNH, or any calculated effect sizes can be derived. All quantitative findings must be considered not reported based solely on the supplied abstract fragment.
Practice implications
This study addresses a clinically important and underexplored population: smokers with asthma, who are frequently excluded from major randomized trials and for whom ICS responsiveness is known to be attenuated. The dual design — a case-control characterization followed by an RCT of triple therapy — is a pragmatic and informative approach to this gap. However, because only a partial abstract was available, no conclusions about efficacy, safety, or the clinical significance of observed characteristic differences can be drawn. The RCT component is limited by its very short treatment duration (1 month), which is insufficient to evaluate exacerbation rates, long-term lung function decline, or durability of response. The exclusive enrollment of male patients in the RCT substantially restricts generalizability to female smokers with asthma. Whether triple therapy (ICS+LABA+LAMA) provides clinically meaningful benefit over dual therapy specifically in this smoking-asthma phenotype remains an open and important question that cannot be answered from the available abstract. __LIMITATIONS__ Abstract is incomplete and truncated — no results are available for either study component; all efficacy and safety conclusions are therefore absent.,RCT: very short treatment duration (1 month) is insufficient to assess exacerbation rates, long-term lung function trajectory, or symptom durability.,RCT: exclusively male enrollment severely limits generalizability to women, who represent a substantial proportion of smokers with asthma.,RCT: small sample size (n=60 total) likely underpowered for clinically meaningful subgroup analyses or detection of modest treatment effects.,Case-control: selection method, eligibility criteria detail, and smoking history quantification (e.g., pack-year threshold) are not described in the available abstract fragment.,No information on blinding status of the RCT is reported, raising potential for performance and detection bias given the open-label nature typical of such small institutional trials.,LAMA agent, dose, and device are not specified in the available abstract.,Funding source is not reported; potential for institutional or industry bias cannot be assessed.,One-month follow-up precludes any safety signal detection for uncommon adverse events.,Smokers with asthma may harbor concurrent asthma-COPD overlap (ACO); diagnostic criteria used to exclude this are not described. __BOTTOM_LINE_CATEGORY__ low_certainty __BOTTOM_LINE__ This two-part Chinese study examined clinical characteristics of smoking versus non-smoking asthma patients and evaluated LAMA add-on therapy in male smokers with moderate-to-severe asthma using a 1-month RCT design; however, the abstract is truncated and no results are available for review. The exclusive enrollment of male patients, a very small sample, and the brief treatment duration represent major constraints on any conclusions that may ultimately emerge. Clinicians managing smoking asthma should be aware that this population remains evidence-poor, and results from this study — once fully published — should be interpreted cautiously pending larger, longer, and more representative trials.