Albuminuria Associated With Lung Function Decline in COPD

In patients with chronic obstructive pulmonary disease (COPD), the presence of albuminuria is associated with greater lung function decline, incident spirometry-defined COPD, and incident COPD-related events, according to the results of a study published in the American Journal of Respiratory and Critical Care Medicine.

Investigators sought to explore whether albuminuria is linked to deterioration in lung function and incident chronic lower respiratory diseases. They examined 6 US population-based cohorts that were harmonized and pooled. Participants were excluded if they had prevalent clinical lung disease. Albuminuria (defined as urine albumin-to-creatinine ratio) was measured with the use of spot samples. Participants’ lung function was evaluated by spirometry. Adjudication and/or administrative criteria were used to classify incident chronic lower respiratory disease-related hospitalizations and deaths. Individual-level associations were adjusted for sex, age, race/ethnicity, weight, height, year of birth, cohort, smoking status, pack-years, renal function, diabetes, hypertension, cardiovascular disease, and medication use.

A total of 10,961 participants with preserved lung function were enrolled in 1 of the 6 study cohorts. Mean age of the patients at the time of albuminuria measurement was 60 years. Overall, 51% of the participants were never-smokers, mean forced expiratory volume in 1 second (FEV₁) decline was 31.5 mL/year, and median albuminuria was 5.6 mg/g. For each standard deviation increase in natural log-transformed albuminuria, the following statistically significant results were observed: a 2.81% greater FEV₁ decline (95% CI, 0.86%-4.76%; P =.0047), an 11.02% greater decline in FEV₁/forced vital capacity (FVC; 95% CI, 4.43%-17.62%; P =.0011), and a 15% increased hazard of incident spirometry-defined moderate to severe COPD (95% CI, 2%-31%; P =.0214).

Every standard deviation in natural log-transformed-albuminuria significantly increased the hazards of incident COPD-related hospitalization/mortality by 26% (95% CI, 18%-34%; P <.0001) in the 14,213 participants who were followed for the development of events. There was no significant association reported for asthma events. Associations persisted in those individuals who were not current smokers, as well as in those who did not have diabetes, hypertension, or cardiovascular disease.

The investigators concluded that the results suggest that endothelial and microvascular mechanisms are both promising targets for the prevention and treatment of COPD. Albuminuria is a noninvasive measure that might be considered when selecting and monitoring high-risk participants who are enrolled in clinical trials of COPD prevention.

Reference

Oelsner EC, Balte PP, Grams ME, et al. Albuminuria, lung function decline, and risk of incident COPD: the NHLBI Pooled Cohorts Study [published online September 28, 2018]. Am J Respir Crit Care Med. doi:10.1164/rccm.201803-0402OC