Study of microalbuminuria in a group of Egyptian COPD patients

Background
Chronic obstructive pulmonary disease (COPD) ranks among the foremost contributors to global morbidity and mortality, with forecasts suggesting it will emerge as the third leading cause of death by 2030. Emerging evidence underscores a robust association between COPD, systemic inflammation, and ensuing cardiovascular complications. Microalbuminuria (MAB), a marker of endothelial impairment and cardiovascular jeopardy, holds potential as a tool for gauging disease intensity in COPD-affected individuals.


Objective
This study aimed to determine the frequency of MAB among COPD patients and explore its linkage to disease severity, as delineated by the global initiative for chronic obstructive lung disease classification, within an Egyptian cohort.


Patients and methods
A cross–sectional analysis was conducted involving 60 COPD patients, all over 40 years of age, enlisted from the Chest Department (wards and ICU) of Ain Shams University Hospitals. After securing informed consent, participants underwent clinical assessments, spirometry for disease staging, arterial blood gas evaluations, and MAB measurement via the urine albumin-to-creatinine ratio. Individuals with urinary tract infections, alternative pulmonary conditions, diabetes, hypertension, dyslipidemia or history of renal disease were excluded. Participants were categorized into MAB-positive or MAB-negative groups based on urine albumin-to-creatinine ratio outcomes.


Results

Of the 60 patients, males predominated (86.7%), with an average age of 58.73±10.75 years (range: 41–84). MAB was detected in 80% of cases (48 individuals), exhibiting urine microalbumin levels of 30–300 µg/l (mean: 103.8±91.8 µg/l). The MAB-positive group experienced a significantly higher annual rate of COPD exacerbations (
P
=0.001) and ICU admissions (
P
=0.005). Compared with their MAB-negative counterparts, MAB-positive patients displayed substantially lower forced expiratory volume in 1 s, forced expiratory volume in 1 s/forced vital capacity ratios, partial pressure of arterial oxygen (PaO₂), and SO₂, alongside elevated partial pressure of arterial carbon dioxide (PaCO₂) levels (
P
<0.001). A urine albumin threshold of 95 µg/l effectively distinguished COPD severity (AUC = 0.787, sensitivity 80%, specificity 75%;
P
<0.001).



Conclusion
MAB exhibits a strong association with COPD severity, offering a cost-effective, non-invasive means to pinpoint patients at heightened cardiovascular risk. Routine MAB screening is recommended for COPD patients, particularly those with advanced disease. Further studies are warranted to elucidate its prognostic utility in COPD management.