Reviewed work: Health effects in COPD smokers who switch to electronic cigarettes: a retrospective-prospective 3-year follow-up

Authors: Riccardo Polosa et al.

Reviewed by: Carrie Wade and Chelsea Boyd

Chronic Obstructive Pulmonary Disease (COPD) is a group of inflammatory lung diseases that causes diminished lung function and results in difficulty breathing. There is no cure; the progression of the disease can only be slowed and the symptoms improved. In developed countries, the primary cause of COPD is smoking and patients are therefore advised to quit in order to slow the disease process. COPD significantly decreases life span and quality of life, which taken together, account for 30.2 million years lost due to early death or disability worldwide.

Although patients are often aware that the cessation of smoking is a key step to improving their quality of life, many find it difficult to abstain, which ultimately exacerbates their condition. And, this is despite the many established smoking cessation treatments and therapies, which simply do not result in long-term abstinence for many COPD patients. In light of this, it has been proposed that e-cigarettes may be an appropriate alternative to conventional quit methods for COPD patients, as they can potentially reduce the risk of relapse while providing a safer form of consumption.

Accordingly, Riccardo Polosa et al. undertook a three-year study of 48 COPD patients who smoke combustible cigarettes and/or e-cigarettes to analyze differences in lung function, quality of life and COPD exacerbations in two ways: 1) they tracked changes from the baseline period within groups (e-cigarette users or combustible cigarette smokers) and compared the trajectory of symptom progression across time (from baseline to 36 months for those who used e-cigarettes and those who did not); and 2) they evaluated differences between groups of patients who exclusively use combustible cigarettes and those who use e-cigarettes (exclusively or as dual users) over the course of three years. The study’s findings reinforced the previous NHIS survey analysis, which found that COPD patients reported improved respiratory symptoms after switching from combustible cigarettes to e-cigarettes. It also extends these findings to include specific measures of disease progression and lung function.

Overall, patients who switched completely to e-cigarettes had favorable outcomes compared to those who continued to smoke and experienced no change in either measure of disease severity. Improvements were demonstrated in three specific measures of respiratory symptoms and disease progression: 1) an improvement in the assessment tool that measures the impact of COPD on patients; 2) a decrease in the number of COPD exacerbations, such as asthma attacks; and 3) increased distance in the six-minute walk test that measures exercise capacity. These improvements were both sustained and significant within the electronic cigarette (EC) group over time (improvements from baseline to 36 months) and also significant between the EC groups (exclusive and dual users) and the smoking group (those who used ECs showed marked improvement compared to the control group).

Perhaps the most interesting finding is that, while officially deemed dual users, those who used e-cigarettes dramatically decreased their use of combustible cigarettes—from 21.9 cigarettes per day when first evaluated to 1.5 cigarettes per day at final evaluation 36 months later. What’s more, this decrease was only observed among the e-cigarette users, as the average cigarette consumption per day among combustible cigarette smokers remained stable throughout the same observation period.

As an observational, COPD patients dictated their own product use throughout the study period. This means that the investigators did not dictate what group people were assigned to but rather that participants self-selected based on the group they felt most accurately represented their usage. The authors compared a control group—COPD patients who exclusively use combustible cigarettes—to a group of COPD patients who use e-cigarettes. In this study population, the relapse rate for the e-cigarette user group (patients who completely discontinued use of e-cigarettes and returned to using combustible cigarettes) was very low. In fact, over the 36-month study period, only two patients (8.3 percent) from the e-cigarette use group returned to exclusive cigarette smoking. Interestingly, other studies have shown that about 50-percent of smokers with COPD who achieved abstinence from combustible cigarettes using traditional quit methods, like Chantix, resumed smoking within one year.

Overall, Polosa et al.’s findings are promising both in terms of the potential for e-cigarettes to assist those with COPD and for what they suggest more broadly about the efficacy of e-cigarettes compared to other smoking cessation methods. One potential drawback to the study that should be noted, however, is the small sample size in terms of patients observed. While the differences between the two groups of patients are statistically significant with a high degree of certainty, studies with larger sample sizes are considered more reliable. However, it is also true that as sample size increases, studies can detect smaller differences between exposure groups and this suggests that a larger sample would also detect a significant association. For these reasons, further investigation to examine the potential for e-cigarettes to act as a substitute for combustible cigarettes on a larger scale is warranted.

And finally, it is important to note that the demonstrated health improvements were significant, but the study only compared populations that did not quit or used e-cigarettes. Using a harm reduction framework, e-cigarettes can be valuable to populations that find quitting difficult and can act as a substitute for combustible cigarettes for those who do not plan to quit or those who relapse. However, to encourage the promotion of e-cigarettes as an appropriate substitute among the medical community, a side-by-side comparison of the trajectory of symptoms and disease progression associated with e-cigarettes and currently approved and promoted treatments (such as nicotine replacement or varenicline) is necessary.

Notwithstanding these avenues for future research, Polosa et al.’s findings could have a significant impact on the 39 percent of COPD patients who continue to smoke after their diagnosis. And, in any event, the study adds to the growing body of literature that indicates switching from combustible cigarettes to e-cigarettes can improve health outcomes, especially among patients already suffering from smoking-related illnesses.