Criner, Cordova, Sternberg & Martinez (2011) worked on the National Emphysema Treatment Trial (NETT), a large-scale multi-center prospective randomized controlled trial that compared various types of treatment for emphysema. It investigated the effects that various treatments have on short- and long-term survival, including pulmonary rehabilitation and lung volume reduction therapy, and compared this information with physiological, genomic and radiographic phenotype. As such, Criner et al. (2011) evaluated the NETT patient population’s emphysema treatment profile in light of their genetic susceptibility to the disease.
A large part of the research focused on the genetics of chronic obstructive pulmonary disease (COPD) and emphysema. It was noted that a severe a1-antitrypsin deficiency is the only proven genetic determinant of the disease (Criner et al., 2011). It was found that several known factors influence the susceptibility to emphysema, including cigarette smokers and familial clustering around the first-degree relatives of patients with COPD. This contrasts with earlier assumptions that emphysema is primarily an environmental disease, and is informative in showing the presentation of the disease. Criner et al. (2011) also note that the NETT genetic ancillary study showed that there were likely various other genetic factors involved in development of the disease, including tumor necrosis factor-a (TNF) and microsomal epoxide hydrolase (EPHX1) disorders.
This is relevant to clinical practice because it is known that only 10-25% of all cigarette smokers develop emphysema (Pillai, 2014). It is useful to understand why this plays a part in the development of the disease for several reasons. Firstly, it can be used to identify those who may be at risk and therefore should be heavily advised against smoking (Criner et al., 2011). It can also be used to predict somewhat the success of treatment. Those with a genetic factor are less likely to respond to traditional treatment options such as pulmonary rehabilitation and may benefit more from a combined treatment involving lung reduction surgery (Criner et al., 2011). This helps to create an understanding of how some patients may or may not respond to treatment in a clinical scenario.
The purpose of this study appears to be to investigate emphysema more thoroughly. As a result, there is a lot of information about the non-genetic aspects of the disease and how it affects patients. Although the focus here is on genetics, it is also useful to understand how other factors, such as the radiographic status of the patient, can play a role. In this way, the research is not particularly focused and therefore lacks in information about certain influences. Overall, the NETT was the largest study ever conducted on emphysema and therefore provides a lot of information that was not previously recognized by the medical community, and therefore remains useful. In an evidence-based context, Criner et al. (2011) summarize the lessons learned about emphysema and therefore the information provided is useful in multiple contexts.
There are a lot of lessons to be learned from such a large study. Firstly, it highlights the difficulty that we have in diagnosing and treating emphysema. Secondly, it highlights areas for further research, including further investigation into the genetic susceptibility factors that were noted but not proven by Criner et al. (2011). Overall, I would recommend this paper because of the depth of information provided about this complex condition. It highlights both new information and compares it to the old information, whilst being considerate of areas which may require further investigation. The large scale of the study means that the results are likely generalizable to a huge number of patients with emphysema, and therefore it is useful in clinical practice.