Advanced Emphysema in African-American and White Patients: Conclusion

Advanced Emphysema in African-American and White Patients: ConclusionThe percentage difference in emphysema severity and distribution between the two groups, based on quantitative CT analysis (Table 5, Fig 4), suggests some variability in lung response to injury caused by smoking, and thus supports the notion of differences in phenotypic expression and burden of disease. To date, no studies have explored racial differences in airway response to cigarette smoking; however, it is noteworthy that African Americans have been shown to have a slower oxidative metabolism of nicotine than whites. Investi-gations pertaining to variability in inflammatory response between various racial groups started to emerge in an attempt to explain susceptibility and heterogeneity of certain inflammatory conditions.
Despite the multicenter nature of the NETT, this study is still limited because of the homogeneity of enrolled patients and the small number of African Americans, which raises the possibility that sampling bias and referral patterns may have influenced the results. Another limitation of the study is the lack of extensive environmental data, the unavailability of description of the cigarette product, and the inherent limitation of questionnaires to fully characterize the smoking behavior. In addition, outcome was not compared between the two racial groups. However, our goal was neither to establish higher susceptibility of one patient group vs another, nor to examine outcome. First, outcome has been already reported, and race was not found to be a significant factor; second, the proportion of African Americans will need to be much higher in order to resolve issues pertaining to race and other environmental factors as potential modifiers of emphysema risk and outcome.
Although the study does not resolve the question of susceptibility, it is the first to extensively characterize African-American and white patients with respect to the most important risk factor, smoking. While it was not surprising to find physiologic and functional similarities between the two races, the fact that African-American patients were younger and smoked less than their white counterparts was not expected. Moreover, African-American patients exhibited a phenotypically different disease pattern based on CT imaging than did demographically matched white patients. Further investigation is needed to determine the factors important in inciting, and then modifying the different patterns of emphysema expressed by the two races.

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