Heterogeneous Disease
COPD has shown to be a heterogeneous disease. As with any other disease, there seems to be very unique and common features to help physicians in the diagnostic process as well as in therapeutic decisions. Long time ago, COPD was considered to be a syndrome based on a reaction to the continuous aggression by cigarette smoking imposed against the beautiful lung airway structure. Patients were considered to have one of two typical expressions of consequences: chronic bronchitis or emphysema.
Santa Klaus maybe had COPD (because of the chimneys?)
There are some patients with more features of chronic bronchitis but we never forget the classical emphysematous patient: skinny, always smoking, with their head among shoulders instead of above them, dry cough, etc, etc. In the meantime, the chronic bronchitis patient was fatter, smiling, coughing and producing sputum, and breathing with difficulty (just imagine Santa Klaus after he inhaled smoke while working…).
Question
The big question is: why some patients show one or other predominant characteristic of the disease? why ones are emphysematous while others have predominant chronic bronchitis?
Some help but different
That reminds us that categories help but are not definite. That reminds physicians that each patient is different to the other although key features may be common. Not all patients respond the same to cigarette smoking injure so they maybe don’t have to respond equally to same therapeutic measures. They even neither have the same behavior nor have the same attitude during the medical office dialogue. Understanding the actual or potential differences may help support a better approach to disease management.
More differences
So, will everybody have same adverse events? will they have same set of surrounding diseases? (which we call comorbidities). Maybe not and perhaps some may be followed up with spirometry, while others need to be followed up with activity levels, or breathlessness (dyspnea) scales, or symptoms exacerbations, or oxygen levels changes, just for mentioning a few couple of parameters.
Changing focus of investigations
These considerations, fortunately, have led some investigators to start talking about different phenotypes of COPD. Although it challenges our current understanding of the disease, already considered complex and under continuous evaluation to make it look simpler, patients and multiple clinical trials have been shown that the damage is not as homogeneous as we could have thought in the population.
Similarities
We also know that in metabolic diseases some patients present different complications (e.g. diabetics with more renal impairment than neuropathy). In hypertension, some have stroke while other have heart predominant damage. They all have different medical approaches and require different directions: some need to loss weigh, others have to change diet, others respond to a drug better than others, etc.
A Disease in evolution
COPD is starting its own cycle of research, adjustment according to the evidence, natural evolution of the crowd of patients, new and contradictory trends in management, followed by more research and so forth. The present is here and now and the hope is increasing thanks to the investigators who have given passion to this issue. Each patient is different because, simply: individuals are not the same.
