Clinical phenotypes in COPD lead to better diagnosis, more targeted treatments
EXPERT ANALYSIS FROM CHEST 2013
Therapeutic implications
Coupling these phenotypes with molecular descriptions of mechanisms and their underlying pathologies can lead to accurate, personalized treatment of COPD. "Phenotypes without clear implications for prognosis and treatment are of little clinical use," Dr. Hanania said, noting that longitudinal studies to validate these phenotypes are necessary.
"Research can help identify mechanisms and courses in different phenotypes, including gender differences," he concluded. "Examining therapeutic responses to different phenotypes can lead to future interventions."
Dr. Hanania disclosed several relationships with a variety of pharmaceutical and medical manufacturers, including Genentech, GlaxoSmithKline* and Astra Zeneca.
Beyond GOLD: A tale of two COPD guidelines
Both address severity and comorbidity, but only one COPD guideline takes into account the latest research on phenotyping in chronic obstructive pulmonary disease.
"The GOLD guidelines do not include clinical phenotypes," said Dr. Joan Soriano, a presenter at the meeting. "But the Spanish ones do."
In fact, there is really only one area where the two documents overlap, said Dr. Soriano: how they define COPD, and even that is not the same. "They both mention the fundamental aspect, which is airflow limitation, and also that the mechanism involved is inflammation," he said. The GOLD definition, however, recognizes the importance of comorbidities, which the Spanish guidelines address the role of tobacco and symptomology.
GOLD (Global Initiative for Chronic Obstructive Lung Disease) is an organization of health care professionals from around the world. "I am not a member of GOLD," Dr. Soriano told the packed session.
The Spanish guidelines are issued by SEPAR, the Spanish Society for Pneumology and Thoracic Surgery. Dr. Soriano is the director of epidemiology and clinical research at the International Center of Advanced Respiratory Medicine (CIMERA) in Palma, Spain.
How the two approach diagnosis also differs. The Spanish guidelines begin with the general COPD diagnosis, then move to the characterization and phenotype, then move to the severity of the disease. They are more specific about age (over 35 years), and have lower limit of normal (LLN) values for persons aged over 70 years and less than 50 years. The GOLD guidelines do not address LLN.
To characterize the disease specifically, the Spanish guidelines address the existence of phenotypes, according to Dr. Soriano, beginning with determining the frequency of exacerbation the patient has per year, and then classifying them eventually into four types: mixed, chronic bronchitis, emphysema, and exacerbator. The GOLD guidelines do not mention phenotypes.
When it comes to the multidimensional assessment of COPD, "the GOLD guidelines lump the mild with the severe spirometry. This is very hard for me to understand," he said. Other classification divergence includes that the Spanish guidelines consider the BODE index.
Treatment in the two guidelines begins similarly, but vectors off from there. "Basically, we are looking at the same trials, so the initial treatments should be short-acting bronchodilators," Dr. Soriano said, but because phenotyping allows for more targeted treatment, the Spanish guidelines offer more detailed treatment options.
In a paper coauthored by Dr. Soriano earlier this year, specific treatment per phenotype included phosphodiesterase-4 inhibitors only for those with chronic bronchitis, inhaled corticosteroids for overlap COPD-asthma, and bronchodilators for infrequent exacerbators (Eur. Respir. J. 2013;41:1252-6).
In the end, the guidelines might not follow the same trajectory, but each has value, he said. "Whatever guidelines you choose, don’t go back and forth. Pick one and use them."
Dr. Soriano reported relationships with Novartis Spain, AstraZeneca, Pfizer, and several other pharmaceutical and medical manufacturers.
*CORRECTION, 2/20/2014: An earlier version of this story misstated the name of GlaxoSmithKline.
