COPD

Albumin: Biomarker for Kidney Disease—And COPD, Too?

For years, albuminuria has been a hallmark indicator of endothelial kidney damage, and new research suggests that it also may have a role in detecting the pulmonary endothelial dysfunction characteristic of chronic obstructive pulmonary disease (COPD).

It has long been known that elevated albumin levels in the urine correspond to microvascular damage—particularly in the renal system, but also throughout the rest of the body, including the pulmonary system. Despite that previously published studies have suggested that albuminuria is higher in patients with COPD, no large prospective study has examined whether an increased urinary level of the protein is associated with the development of COPD.

In the new study,1 investigators analyzed data on 31,877 participants in 6 population-based observational cohort studies funded primarily by the National Heart, Lung, and Blood Institute. The average age of the participants was 60. After excluding participants with COPD or asthma, they monitored the lung function of the participants for a median of 6 years and recorded respiratory disease–related hospitalizations and death for a median of 15 years.

The results showed that, even after adjusting for participants’ smoking history and the presence of diabetes, hypertension, and/or cardiovascular disease, each standard deviation increase in albuminuria was associated with the following outcomes:

  • A 15% increase in participants who developed moderate to severe COPD
  • A 26% increase in COPD hospitalizations and deaths
  • A 3% greater decline in FEV1 (forced expiratory volume in the first second of expiration)
  • An 11% greater decline in FEV1 to FVC (forced vital capacity) ratio

The investigators noted that findings were similar in participants with a smoking history as well as those who had never smoked. They concluded that this study “adds to mounting evidence supporting a role for pulmonary endothelial dysfunction in COPD pathogenesis, suggesting that microvascular mechanisms may be promising targets for COPD prevention and treatment.”

—Michael Gerchufsky

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.