The Impact of Extreme Heat Waves and Air Pollution on the Prognosis of Chronic Airway Diseases

NCT07261774 | Completed

• 1 other identifier: MU-2024/097
• Study Type: observational
• Target: 96
• Locations: 1 country
• Sites: 1

Brief Summary

Extreme heat waves (EHW) and air pollution exacerbate chronic airway diseases, but little is known about how these environmental stressors affect quality of life, airway inflammation, symptom control, and pulmonary function. This study was designed to determine the impact of EHW and air pollution on asthma and COPD. This was a prospective cohort study conducted among individuals with asthma and COPD in Mersin, Türkiye, between February 14 and December 1, 2024. Meteorological and air quality index (AQI) data were obtained from official sources. Participants underwent pulmonary function tests (PFTs) and fractional exhaled nitric oxide (FeNO) measurements during periods of normal weather conditions and repeated assessments during documented EHW periods. Patient-reported outcomes included the Asthma Control Test (ACT) and Asthma Quality of Life Questionnaire (AQLQ) for asthma, and the Modified Medical Research Council (mMRC) scale and COPD Assessment Test (CAT) for COPD. Exacerbation episodes requiring systemic corticosteroid use or hospitalization were also recorded. The study aimed to evaluate the effects of EHW and air pollution on disease control, quality of life, lung function, airway inflammation, and exacerbation burden in patients with asthma and COPD.

Conditions

Asthma (Diagnosis); COPD (Chronic Obstructive Pulmonary Disease)

Keywords

Asthma; COPD; Extreme Heatwave; Air Pollution; Climate Change

Outcome Measures

Primary Outcomes (1)

• Change in FeNO levels during extreme heat waves vs seasonal normal conditions

  Fractional exhaled nitric oxide (FeNO) (parts per billion (ppb)) measured using the Bedfont® NObreath device.

  Participants were evaluated twice over a 292-day period, from February 14, 2024, to December 1, 2024 (once during seasonal normal conditions and once during extreme heat waves).

Secondary Outcomes (1)

• Exacerbation frequency in asthma and COPD patients during extreme heat waves vs seasonal normal conditions

  Participants were evaluated twice over a 292-day period, from February 14, 2024, to December 1, 2024 (once during seasonal normal conditions and once during extreme heat waves).

Other Outcomes (6)

• 2. Change in FEV1 during extreme heat waves vs seasonal normal conditions

  Participants were evaluated twice over a 292-day period, from February 14, 2024, to December 1, 2024 (once during seasonal normal conditions and once during extreme heat waves).

• 3. Change in FVC during extreme heat waves vs seasonal normal conditions

  Participants were evaluated twice over a 292-day period, from February 14, 2024, to December 1, 2024 (once during seasonal normal conditions and once during extreme heat waves).

• 4. Change in ACT score (Asthma Control Test) during extreme heat waves vs seasonal normal conditions

  Participants were evaluated twice over a 292-day period, from February 14, 2024, to December 1, 2024 (once during seasonal normal conditions and once during extreme heat waves).

Study Arms (2)

Asthma Group

Patients with physician-diagnosed asthma who met the inclusion criteria and were followed during periods of extreme heat waves and normal seasonal weather.

COPD Group

Patients with physician-diagnosed chronic obstructive pulmonary disease (COPD) who met the inclusion criteria and were followed during periods of extreme heat waves and normal seasonal weather.

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

The study population will consist of adult patients (≥18 years) diagnosed with asthma according to the GINA 2024 guidelines or COPD according to the GOLD 2024 guidelines, who are in a stable phase for at least four weeks. Participants must provide written informed consent and reside within the central district of Mersin. Patients with other chronic lung diseases, history of lung surgery, recent respiratory infections, active tuberculosis, significant comorbidities affecting lung function, pregnancy, active smoking within the past year, cancer history within the past five years, or those living outside Mersin city center will be excluded.

You may qualify if:

• Age ≥ 18 years
• Provision of written informed consent
• For the asthma group:
• \- Diagnosis of asthma for at least 6 months according to the GINA 2024 guidelines
• Variable respiratory symptoms together with documented variable expiratory airflow limitation, demonstrated by at least one of the following:
• Positive bronchodilator reversibility test (\>12% and \>200 mL increase in FEV1 10-15 minutes after 400 μg salbutamol)
• Peak expiratory flow (PEF) variability (\>10% average daily PEF variability over 2 weeks)
• Positive delayed reversibility (improvement in lung function after 4 weeks of anti-inflammatory treatment with \>12% and \>200 mL increase in FEV1 or \>20% increase in PEF)
• Positive bronchial provocation test (≥20% fall in FEV1 with standard doses of methacholine or histamine)
• Stable disease for at least 4 weeks prior to enrollment
• For the COPD group:
• Diagnosis of COPD for at least 6 months according to the GOLD 2024 guidelines (post-bronchodilator FEV1/FVC \<70% in the presence of compatible clinical findings)
• Stable disease for at least 4 weeks prior to enrollment

You may not qualify if:

• Presence of other pulmonary diseases apart from asthma or COPD (e.g., interstitial lung diseases, pleural diseases, pulmonary vascular diseases)
• Pregnant women
• History of cancer within the past 5 years
• Previous lung surgery
• Active pulmonary tuberculosis
• Respiratory tract infection within the last 4 weeks
• Presence of significant extrapulmonary disease that may affect lung function (e.g., cerebrovascular disease, acute myocardial infarction)
• Active smoking within the past year
• Residence outside the central district of Mersin

Sponsors & Collaborators

• Mersin University: lead

Study Sites (1)

Mersin University Faculty of Medicin

Mersin, Mersin, Turkey (Türkiye)

Location

MeSH Terms

Conditions

Asthma; Disease; Pulmonary Disease, Chronic Obstructive

Condition Hierarchy (Ancestors)

Bronchial Diseases; Respiratory Tract Diseases; Lung Diseases, Obstructive; Lung Diseases; Respiratory Hypersensitivity; Hypersensitivity, Immediate; Hypersensitivity; Immune System Diseases; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Chronic Disease; Disease Attributes

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Prof. Dr.

Study Record Dates

• First Submitted: August 29, 2025
• First Posted: December 3, 2025
• Study Start: March 6, 2024
• Primary Completion: November 7, 2024
• Study Completion: December 1, 2024
• Last Updated: December 3, 2025

Record last verified: 2025-09

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)