Advanced Emphysema in African-American and White Patients: Discussion

Advanced Emphysema in African-American and White Patients: DiscussionFew doubt that the answer lies in the complex genotype/environment interactions, but the extent to which each factor plays in the pathogenesis of emphysema is enigmatic. Except for a1-antitryp-sin deficiency, no studies have identified other “emphysema genes” that distinguish the remaining 99% patients with emphysema. Studies are starting to unveil some potential genetic markers and risk factors that could be implicated in the pathogenesis of emphysema. Among these are tumor necrosis factor-a and matrix metalloproteinase-1 and matrix metalloproteinase-12 polymorphisms. Currently, although genetic familial studies are underway, they include few African-American patients. in detail
Similarly, no studies have addressed the possible role of research artifact and selection bias as contributors to the observed racial differences. Van de Mheen and Gunning-Schepers described numerous factors, independent of biological differences, that could account for the significant variability in relative risk of smoking on various smoking-related diseases. Examples of such factors that could contribute to the racial emphysema gap could be related to racial bias in the diagnosis of emphysema, and a higher attrition of African-American patients from nonpulmonary morbidities caused by smoking.
The reported prevalence of emphysema has been reported to be twofold to threefold higher in white patients than in African-Americans patients, but in this study there was a 20 to 1 ratio of white vs African-American patients, consistent with significant underrecruitment of African-American patients. In addition to factors pertaining to patient recruitment and regional or locational sites of treatment, the design of the NETT has probably accentuated the two aforementioned factors because the clinical costs of NETT were paid predominantly by Medicare. It is noteworthy that patients become eligible for Medicare if they are disabled or > 65 years old, and that many African Americans in this study were < 65 years old. If African-American patients with emphysema truly tend to present earlier in life than white patients, they would not have been able to enroll in the NETT unless their health insurance companies agreed to pay clinical costs. Moreover, and similar to other large trials, patients with significant cardiovascular disease, which is more prevalent in African Americans, were excluded.

This entry was posted in Emphysema and tagged African American, copd, CT, emphysema, epidemiology, pulmonary function testing, radiography.