A new study has found that muscle loss can lead to increased rates of mortality and morbidity in patients with chronic obstructive pulmonary disease (COPD). However, one expert remains skeptical whether the study represents the full scope of patients at risk.
Muscle loss phenotype in patients with chronic obstructive pulmonary disease (COPD) can lead to higher rates of in-hospital mortality, length of stay and health care costs than patients without the phenotype, according to a new study published in Respirology.
COPD is currently the third leading cause of death worldwide and fourth in the United States. Patients with advanced forms of the condition experience skeletal muscle loss associated with adverse clinical outcomes such as higher mortality, decreased quality of life, and more severe and frequent exacerbations than patients with milder COPD.
“Our observations lay the foundation for developing strategies and allocating resources at the national level to develop targeted interventions to improve clinical outcomes and decrease health care utilization and costs in patients with COPD,” said the investigators.
The study revealed that patients who received a diagnosis of muscle loss phenotype secondary to their COPD who experienced COPD-related hospitalizations in 2011 (12,977) had significantly higher in-hospital mortality (14.6% vs 5.7%; P <.001) and mean (SD) length of hospital stay (13.3 [17.1] vs 5.7 [7.6]; P <.001) than those without muscle loss phenotype.
Additionally, the average hospital charge was $13,947 for each patient with COPD and muscle loss phenotype vs $6610 for patients with COPD and no diagnosis of muscle loss phenotype (P <.001).
“There were also likely additional indirect costs associated with a muscle loss phenotype, given that a higher proportion of these patients required transfer to skilled nursing facilities, intermediate care facilities and home health care,” said the investigators.
They noted that the mean (SD) age of hospitalized patients with COPD exacerbation was 67.5 (14.5) years, suggesting that the higher age of those in the muscle loss phenotype cohort may attribute to an increase in mortality rates, as it is known that elderly patients naturally experience a loss of skeletal muscle mass in addition to the muscle loss associated with COPD.
The investigators suggested that COPD-related sarcopenia could be curbed in patients with muscle loss phenotype with the implementation of pulmonary rehabilitation and increased nutrient intake, claiming that exercise training can improve quality of life and reduce health care costs, hospital readmissions, and mortality.
“Our study highlights the societal impacts of muscle loss phenotype and the need for exercise training and nutritional programmes targeting this high-risk population,” said the investigators.
However, Bartolome R. Celli, MD, a professor of medicine at the Harvard Medical School took issue with the investigators’ suggestion in an editorial he wrote on their results, saying that pulmonary rehabilitation has not yet been proven successful if implemented early and patients are unlikely to continue after hospital discharge. Additionally, increasing nutrition intake may only show modest results at best.
Celli also pointed out that the investigators’ use of the International Classification of Diseases-9 (ICD-9) codes to detect the presence of muscle loss likely contributed to an underestimation of the actual number of patients with COPD suffering from muscle loss because ICD-9 billing codes do not recognize muscle loss as an independent entity.
“This, in of itself, is a pity because very little attention has been given to some of the systemic consequences of COPD, particularly the problem of muscle attrition and dysfunction,” he wrote Celli.
The investigators used ICD-9 codes listed in the Nationwide Inpatient Sample database to expand the scope of conditions that are associated with sarcopenia, as more updated billing code systems are used more often to refer to muscle loss related to age rather than chronic diseases.
“Our observations lay the foundation for developing strategies and allocating resources at the national level,” the authors concluded, “to develop targeted interventions to improve clinical outcomes and decrease health care utilization and costs in patients with COPD.”
Attaway AH, Welch N, Hatipoğlu U, Zein JG, Dasarathy S. Muscle loss contributes to higher morbidity and mortality in COPD: An analysis of national trends. Respirology. Published June 16, 2020. doi:10.1111/resp.13877