#1218 Investigating the association of chronic obstructive pulmonary disease with outcomes in patients with non-dialysis dependent chronic kidney disease
Authors: Merlino Lino , Rainone Francesco , Chinnadurai Rajkumar , Battini Graziana , Trivelli Marco , Colombo Paolo , Kalra Philip A 
Published: May 2024

Abstract

Background and Aims
Kidneys and lungs have a strong pathophysiological link. However, studies on the association between chronic conditions involving these two organs, chronic kidney disease (CKD) and chronic obstructive pulmonary disease (COPD), are limited. Nephrologists better understand the pathophysiology and management of acute manifestations of these two organs' dysfunction, i.e., pulmonary-renal syndrome accompanying vasculitis, compared to their chronic alterations. Our study aims to investigate the prevalence and association of COPD with adverse outcomes in patients with CKD (stages 3-5).

Method
This retrospective observational cohort study was conducted on CKD patients (stages 3-5) enrolled in the Global Collaborative Network (GCN) of the TriNetX research platform between the years 2003 and 2023. TriNetX provides access to anonymized electronic medical records across large healthcare organizations (HCOs). This report includes patients from 112 HCOs with different demographic backgrounds. The study compared outcomes of patients aged 18-80, with and without COPD, in a propensity score matched (PSM) cohort of CKD patients. The characteristics included in the PSM were age, sex, ethnicity, comorbidities (neurological, hematological, cardiovascular, gastroenterological, and endocrine conditions) and baseline serum creatinine. The proportional hazard assumption was tested using the generalized Schoenfeld approach built in the TriNetX platform. A 95% confidence interval (95% CI) was considered evidence of statistical significance throughout the analyses. The Kaplan- Meier (KM) method was used for the survival probability. Statistical significance was defined as p-value &lt; 0.05. Outcome events were included 180 days after the index event (COPD diagnosis) and ended 3650 days after.

Results
Of the total of 1 045 536 CKD patients, 181 207 had a co-existent diagnosis of COPD (prevalence rate—17.3%). A PSM generated a matched cohort of 174 308 patients each. The mean age of the cohort was 66.7 ± 7.9 years, with a predominance of white ethnicity (65.8%) and an equal male-to-female ratio. 73.1%, 51.5%, 69.6%, 54.1%, and 37.2% had a history of cardiovascular, nervous system, endocrine, gastroenterological, and hematological disease, respectively. The mean serum creatine at baseline was 1.3 ± 1.2 mg/dL. The comparison of differences in the outcomes on follow-up between the matched cohorts is illustrated in Table 1. CKD patients with concomitant COPD had a higher all-cause mortality (17.3% vs 8.7%, p &lt; 0.0001), higher all-cause hospitalizations (14.7% vs 12.7%, p &lt; 0.0001), and higher cardiovascular events. Proportional hazard models showed that COPD is a strong risk factor associated with all-cause mortality (HR: 2.189; 95% CI (2.13-2.22, p &lt; 0.0001)), hospitalizations (HR:1.39; 95% CI (1.36–1.44); p &lt; 0.0001), and other cardiovascular and mental health illness (Table 1). KM chart illustrates the differences in survival probability between the two groups (Log-Rank p &lt; 0.001) (Fig. 1).

Conclusion
Our ‘real-world data’ findings emphasize that patients with CKD and COPD are a cluster that requires special attention due to poorer outcomes. Given the high frequency of these associations between these two chronic conditions, an improved awareness is warranted among the nephrological community.