Clinical Research Directory

Inclusion Criteria: * To be eligible for the study, patients were required to meet all of the following criteria: 1. Age: Patients aged between 18 and 80 years. 2. COPD Diagnosis: A confirmed diagnosis of COPD according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria, including: * A post-bronchodilator forced expiratory volume in one second (FEV1) to forced vital capacity (FVC) ratio of \<0.70. 3. Renal Failure: Evidence of CKD, defined as: * An estimated glomerular filtration rate (eGFR) of \<60 mL/min/1.73 m² (Stages 3-5 CKD) on at least two occasions three months apart, or a history of renal replacement therapy. 4. Stable Medical Condition: Clinically stable COPD, with no exacerbations or hospital admissions within the preceding four weeks. Exclusion Criteria: * Patients were excluded from the study if they met any of the following criteria: 1. Acute Exacerbation: Evidence of an acute COPD exacerbation within four weeks prior to enrolment. 2. Other Respiratory Disorders: Coexistence of other chronic respiratory diseases such as asthma, interstitial lung disease, or bronchiectasis that might interfere with the assessment of COPD. 3. Renal Transplantation: History of kidney transplantation, as immunosuppressive therapy may affect disease progression and outcomes. 4. Uncontrolled Comorbidities: Presence of any uncontrolled comorbid conditions, including: * Cardiovascular instability or recent myocardial infarction (within six months). * Active malignancy (other than localized skin cancer). * Severe liver disease (e.g., cirrhosis with hepatic failure). 5. Pregnancy or Breastfeeding: Women who were pregnant or breastfeeding at the time of study enrolment. 6. Cognitive Impairment: Any condition that would impair the ability to provide informed consent or participate in study procedures, such as dementia or significant psychiatric disorders.