CD4 Cell Count May Indicate COPD Risk in HIV-Positive Patients

Higher smoking rates in HIV-positive patients may contribute to COPD diagnoses.

The risk of comorbid chronic obstructive pulmonary disorder (COPD) in patients infected with the human immunodeficiency virus (HIV) may be underestimated and needs to be part of routine screenings, according to a new French study.

Researchers found that 9% of patients with HIV in the study had COPD, in comparison with about 7.5% of the French general population. In 90% of the HIV/COPD cases, the patients reported they had never been tested or treated for COPD. Depleted CD4 cells, a marker for HIV, may also serve as a flag for COPD.

“Our study confirmed literature suspicion and found for the first time in a large cohort of patient[s] a significant and independent correlation between COPD and CD4 cell count defect,” Karine Risser MD, and her colleagues wrote. Risser is from the Service d’Infectiologie, Centre Hospitalier Universitaire de Nice in Nice, France.

The cross-sectional study was conducted at Nice University Hospital where the cohort included 2,453 HIV-positive patients. Of those, 93% were taking antiretroviral therapy (ART) and 83% had no detectable viral load. From that group, the researchers selected 623 who were representative of the entire cohort. Out of those patients, 73.8% were men, the mean age was 48, the mean duration of HIV infection was 15.5 years, and the mean CD4 cell count was 622 cells per cubic millimeter (mm³).

CD4 cells protect the immune system and are attacked by the HIV virus. A normal number of CD4 cells ranges from 500 to 1,000 mm³ of blood.

The researchers reported that two HIV markers negatively correlated with COPD. They were nadir CD4 cell count (188 CD4 cell/mm³ in COPD patients vs. 262 CD4 cells/mm³ in non-COPD patients) and a CD4 cell count where the odds of COPD decreased (OR, 0.77) with each increase of a 100 CD4 cells/mm³.

“The existence of an independent correlation between CD4 cell count and COPD should suggest to clinicians to be aware of COPD risk for patients with less than 200 CD4 cells/mm³ and particularly if these patients are smokers,” the authors wrote.

People with HIV often are smokers at a rate of two to the three times the general population, research has found. More than 50% of the study’s population sample were current smokers compared with 33% in the French general population. Cigarette smoking “accounts for 95% of toxic respiratory exposure responsible for COPD in industrialized countries. These results are alarming, especially because the attributable risk associated with smoking among HIV-infected patients is doubled compared to uninfected population” the team continued.

Previous smaller studies have reported an increased prevalence of COPD among patients with HIV, ranging from 6% to 21% in other industrialized countries.

“Under-diagnosis of COPD in the general population is a well-known problem and has also been identified in HIV-infected patient populations,” the authors wrote. “As patients are frequently asymptomatic (42% of our COPD patients), the guidelines and criteria for COPD screening appear to be insufficient. Further studies are required to identify more appropriate strategies to screen for COPD in this population.”

The study, “COPD in HIV-Infected Patients: CD4 Cell Count Highly Correlated,” was published in PLOS ONE.

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