Early Screening of Young COPD and Pre-COPD

1. Basic information and related definitions: The basic information included age, gender, body mass index (BMI), smoking status (smoking index, passive smoking), biomass exposure, occupational exposure history of dust/gas/smoke, and family history of respiratory diseases. Participants' smoking status was categorized as never smoked, former smoker, or current smoker. Never smoked was defined as having smoked fewer than 100 cigarettes in the past. Current smoking was defined as baseline smoking. Previous smoking was defined as having smoked more than 100 cigarettes previously but not smoking for at least 6 months before baseline. The smoking index was defined as the number of packs of cigarettes smoked per day multiplied by the number of years smoked. Passive smoking was defined as smoke inhalation by non-smokers living with smokers for more than 1 year. Biomass exposure was defined as the use of biomass such as wood, crop residue, charcoal, grass, and manure for more than 1 year. Exposure to occupational dust/gas/smoke was defined as occupational exposure to dust/gas/smoke for more than 1 year during the lifetime of the subject. Family history of respiratory disease was defined as respiratory disease in parents, siblings, and childhood (e.g., chronic bronchitis, emphysema, asthma, COPD, cor pulmonalis, bronchiectasis, lung cancer, interstitial lung disease, obstructive sleep apnea-hypopnea syndrome) and a further visit to assess medication use history. Clinical symptoms included cough, expectoration, shortness of breath after exercise, suffocating wheezing, and dyspnea. Clinical symptoms were defined as the above symptoms not caused by other clear causes, and the cumulative time was not less than 2 months per year.
2. Questionnaire scores: ① Modified dyspnea scale (mMRC) : mainly used to evaluate the degree of dyspnea in COPD patients. The scale ranges from 0 to 4, with higher grades indicating more severe dyspnea, with grades 1 and 2 indicating "mild-to-moderate dyspnea," and grades 3 and 4 indicating "severe to very severe dyspnea. ②CAT score: a total of 8 questions covering symptoms, activities and conditions. Each question corresponds to a 0-5 point option on a 40-point scale, with higher scores indicating worse health status.
3. Pulmonary function: it was determined that the enrolled patients should stop using drugs that affect the test results and avoid related influencing factors before bronchodilation. Professional staff guided the patients to carry out respiratory training, and completed pulmonary ventilation and diffusion function tests. Ventilatory function was measured before and 15 minutes after inhalation of a bronchodilator (albuterol). forced vital capacity (FVC) and its percentage of predicted value (FVC%pred), forced expiratory volume in one second (FEV1) were recorded accurately. FEV1) and its percentage of predicted value (FEV1%pred), FEV1/FVC, maximum minute ventilation volume (MVV) and its percentage of predicted value (MVV%pred). The maximum midexpiratory flow (MMEF) was calculated. Diffusion capacity (DLCO) was measured by taking four to five quiet breaths in a single breath, then exhaling deeply to RV position, inhaling quickly to TLC position, holding breath for 10 seconds, and exhaling all the gas to RV position. (3) Pulmonary function: it was determined that the enrolled patients should stop using drugs that affect the test results and avoid related influencing factors before bronchodilation. Professional staff guided the patients to carry out respiratory training, and completed pulmonary ventilation and diffusion function tests. Ventilatory function was measured before and 15 minutes after inhalation of a bronchodilator (albuterol). forced vital capacity (FVC) and its percentage of predicted value (FVC%pred), forced expiratory volume in one second (FEV1) were recorded accurately. FEV1) and its percentage of predicted value (FEV1%pred), FEV1/FVC, maximum minute ventilation volume (MVV) and its percentage of predicted value (MVV%pred). The maximum midexpiratory flow (MMEF) was calculated. Diffusion capacity (DLCO) was measured by taking four to five quiet breaths in a single breath, then exhaling deeply to RV position, inhaling quickly to TLC position, holding breath for 10 seconds, and exhaling all the gas to RV position. (5) Six-minute walk test: The enrolled patients were performed on a flat, straight corridor with a length of 30 meters. They avoided strenuous activities within 2 hours before the test and could carry a cane or walking aid to the test. Blood pressure, pulse, and oxygen saturation were measured. Then the subjects were asked to walk as much as possible along the established route within six minutes. If they felt tired, they could slow down or rest in place and continue walking as soon as possible. At the end of the six minutes, the subjects were allowed to stay in place, and their blood pressure, pulse, and oxygen saturation were rapidly measured again, and their total distance walked was recorded.

Objects and methods of intervention According to the results of pulmonary function test, patients diagnosed as early COPD or pre-COPD were given triple bronchial inhalation therapy according to the principle of voluntary, and professional staff were arranged to explain relevant knowledge, answer questions and guide medication. Each patient was asked to record medication use.

Follow-up time and endpoint indicators The patients were followed up for 1 year from the date of enrollment. The clinical symptoms, pulmonary function parameters, and imaging parameters of early COPD and pre-COPD patients with or without triple bronchial inhalation drug use were recorded, focusing on the annual decline in FEV1% pred, FEV1/FVC and DLCO.