Chronic obstructive pulmonary disease (COPD) was found in 9% of people living with HIV in a large French cohort -- and most (77%) of the cases were previously undiagnosed, according to the results of a study presented at ICAAC 2014 in Washington, D.C., by Karine Risso, M.D., of Nice University Hospital in France.
The study also evaluated risk factors for COPD, and found that in addition to already known risks, such as smoking and age, low CD4 cell counts were independently predictive of COPD. Given the low rates of diagnosis, and the serious progressive nature of COPD, Risso recommended a screening algorithm with six simple parameters to identify high-risk patients (see below).
COPD is a progressive lung disorder, which is associated with airway inflammation, fibrosis and the destruction of lung tissue that limits airway elasticity. Upon exertion, the lungs may become hyper-inflated due to air trapping, limiting airflow and ultimately making physical activity difficult.
In industrialized countries, 95% of the cases are linked to smoking, although aging is also a clear risk factor. Although there are preventive measures (including, obviously, smoking cessation) and treatments that can slow the progression of COPD and ameliorate symptoms, they cannot completely reverse the condition once it is established.
Other studies in a population of older French adults (45 years and older) found the prevalence to be 7.5%, while the global estimates in older adults ranged from 9%-10%. Consequently, COPD is now believed to be the third most common cause of death globally.
Despite effective highly active antiretroviral therapy (HAART), a growing number of studies have begun to propose that COPD may be an emerging issue in people living with HIV for a number of reasons:
- Despite immune recovery, respiratory complaints are more common and there are more lower respiratory tract infections among people living with HIV than in the general population.
- People living with HIV are two to three times more likely to smoke.
- Studies have estimated that as many as 15% - 23.4% of people living with HIV are at risk of COPD.
- Some studies have suggested that HIV itself may have a role in the development of COPD, while others have questioned whether antiretroviral treatment (ART) or specific antiretrovirals might be associated with a greater risk of developing COPD.
The Nice University Hospital Study
Risso and her colleagues conducted a cross-sectional study in a large cohort of HIV-infected outpatients who visited the Nice University Hospital from Jan. 1 to Dec. 31, 2012, evaluating the prevalence of COPD with strict spirometry (a breath test measuring lung function), potential risk factors for COPD, and whether there were factors that could help predict which patients to screen for COPD. Patients were excluded if they were under the age of 18, had had a lower respiratory infection within the last two months, or were physically or mentally unable to perform spirometry.
Of the 623 patients who were screened, 42 (6.7%) were excluded for meeting one of the exclusion criteria, leaving 581 for the analysis. The median age was 48.3 years and 73.8% were male. The mean CD4 count was 622 and about 85% had an undetectable viral load. Fifty percent were current smokers and about 72% were current or past smokers. Additionally, about 23% had reported respiratory symptoms in the past.
The prevalence of COPD among these patients was 9% (52/581). Approximately three quarters were unaware of their diagnosis. Only 9% had ever performed spirometry before, and only 9% were receiving any respiratory therapy.
COPD had gone undiagnosed despite the frequency of smoking in the cohort, the frequency of respiratory complaints and the existence of international guidelines on COPD screening.
A number of factors were significantly associated with COPD in univariate analyses, including: older age, lower BMI (body mass index), ever smoking, ever having used cannabis, injecting drugs, HCV (hepatitis C virus) coinfection, depression, longer duration of HIV infection, lower CD4 count, lower viral load and lower nadir CD4 count. Most of the cohort was on treatment so ART exposure was not significantly associated with COPD risk, nor was exposure to specific classes of antiretrovirals associated with COPD risk.
The following factors were independently related to COPD risk, according to the multivariate analysis:
- Age (OR [odds ratio]: 1.61; P = .007)
- BMI (OR: .78; P < .001)
- Pack-year history (OR: 1.28; P = .003)
- CD4 count (OR: .77; P < .001)
Risso and colleagues also found that the following factors were strong predictors of two-to-four times more COPD risk:
- Age > 50 years (OR 2.37; P = .017)
- BMI < 21 kg/m2 (OR 4.07; P < .001)
- Current/past smoking (OR 3.40; P = .031)
- Respiratory symptoms (OR 3.49; P < .001)
- Previous lower respiratory infection (OR 2.37; P = .006)
- CD4 count < 500 (OR 2.19; P = .027)
The take-home message, according to Risso, is that clinicians should be alert to the possibility of COPD in people living with HIV who smoke and have respiratory complaints. COPD is common and frequently goes undiagnosed. Clinicians should strive to improve their smoking cessation strategies and screen for COPD, particularly in their patients who have the predictive risk factors.
Finally, Risso believes more research is needed to assess what possible role lower CD4 counts might have in the development of COPD. She posits that it may be related to bronchial pneumocystis or other pathogen colonization or inflammation with some other HIV-related acceleration of the aging process.
Theo Smart is an HIV activist and medical writer with more than 20 years of experience.