Background Chronic kidney disease (CKD) is a frequent but under-recognized comorbidity in severe chronic obstructive pulmonary disease (COPD). We aimed to determine the prevalence of renal dysfunction and its association with comorbid conditions in patients hospitalized with severe COPD.

Methods Retrospective analysis of 328 patients (71.9% male, mean age 65.4 ± 0.77 years) with GOLD stage III–IV COPD admitted to the Pulmonology Department, Multiprofile Clinic of Tashkent Medical Academy, between 2020 and 2023. Estimated glomerular filtration rate (eGFR) was calculated using the 2021 CKD-EPI creatinine equation. Renal dysfunction was defined as eGFR <90 mL/min/1.73 m². Comorbidities, smoking status, dyspnea (mMRC), SpO₂, and proteinuria were recorded.

Results Renal dysfunction was present in 106 patients (32.3%). Patients with renal dysfunction were older (69.5 ± 1.2 vs. 63.6 ± 0.9 years, p<0.001), had longer COPD duration, more severe dyspnea, lower SpO₂, and higher prevalence of proteinuria (79.2% vs. 60.8%, p<0.001). Cardiovascular and metabolic comorbidities were significantly more frequent in the reduced-eGFR group: ischemic heart disease (89.6% vs. 79.3%), arterial hypertension (70.8% vs. 50.0%), diabetes mellitus (28.3% vs. 20.7%), diagnosed CKD (24.5% vs. 2.7%), obesity (22.6% vs. 9.9%), and bronchial asthma overlap (13.2% vs. 4.5%) (all p<0.05). Multivariable logistic regression identified age (OR 1.07, 95% CI 1.04–1.10), ischemic heart disease (OR 2.31, 95% CI 1.12–4.76), and arterial hypertension (OR 2.18, 95% CI 1.26–3.78) as independent predictors of renal dysfunction.

Conclusion Renal dysfunction affects approximately one-third of patients with severe COPD and is strongly associated with cardiovascular and metabolic comorbidity. Routine eGFR calculation is warranted in all severe COPD patients, even in the absence of overt renal symptoms, to enable early nephrology referral and risk stratification.

COPD, chronic kidney disease, glomerular filtration rate

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