HIV is associated with an increased risk of lung disease with infectious and non-infectious causes, US investigators report in the American Journal of Respiratory and Critical Care Medicine.
The study was conducted in the era of modern antiretroviral treatment, and bacterial pneumonia and chronic obstructive pulmonary disease were the most common lung diseases seen in patients with HIV.
The investigators found evidence that a higher CD4 cell count, a low viral load and taking HIV treatment were protective against lung disease, even some that did not have an infectious cause.
There was also evidence that older age increased the risk of pulmonary complications, adding lung conditions to the diseases of ageing that are of concern for people with HIV.
In the era before effective antiretroviral treatment was introduced, lung disease was an important cause of serious illness and death in people with HIV. Some research suggests that individuals with HIV continue to have an increased risk of lung problems, including those with non-infectious causes.
Investigators from the US Department of Veterans’ Affairs wished to gain a better understanding of the risks of pulmonary complications for patients with HIV. They therefore compared the incidence of diseases with infectious and non-infectious causes between 33,420 HIV-positive patients and 66, 840 HIV-negative individuals. Analyses were also performed to see if any specific factors were associated with lung disease for those with HIV.
Both groups were well matched demographically. The median age was 45, the overwhelming majority were male, and over 40% were African American.
Prevalence of alcohol abuse (21% vs. 19%), drug use (23% vs. 15%) and hepatitis C infection (30% vs. 11%) was higher amongst those with HIV. In addition, patients with HIV were significantly more likely to smoke (80% vs. 76%, p < 0.001).
At baseline, the patients with HIV had a median CD4 cell count of 264 cells/mm3 and two-thirds were taking antiretroviral therapy.
On entry to the study, 7% of those with HIV and 6% of HIV-negative patients had one or more pulmonary conditions. This difference was significant (p < 0.01). Patients with HIV were more likely to have lung disease with infectious and un-infectious causes.
HIV-positive patients were significantly more likely to develop new lung diseases. Bacterial pneumonia and chronic obstructive pulmonary disease were the two most common conditions. The incidence of bacterial pneumonia was 28 per 1000 person years among those with HIV compared to 6 per 1000 person years for HUIV-negative patients (p < 0.001). Similarly, incidence of chronic obstructive pulmonary disease was also markedly higher among patients with HIV (23 vs. 17 cases per 1000 person years, p < 0.001).
Although quite rare, lung cancer, pulmonary hypertension and pulmonary fibrosis were all significantly more likely to occur in those with HIV (all p < 0.001).
Unsurprisingly, patients with HIV also had higher incidence rates of PCP pneumonia and tuberculosis.
With the exception of PCP and asthma, the incidence of all pulmonary disease increased with age. This was true for both HIV-positive and HIV-negative patients.
The investigators calculated that even after adjusting for smoking, those with HIV had an increased risk of developing every kind of pulmonary disease with the exception of asthma.
Attention was then focused on the factors that increased the risk of lung disease for patients with HIV.
A higher CD4 cell count and a viral load below 400 copies/ml was associated with a lower risk of diseases with infectious causes such as bacterial pneumonia, PCP and tuberculosis.
In addition, incidence of chronic obstructive pulmonary disease and asthma was significantly lower in patients taking HIV treatment, with an undetectable viral load reducing the risk of obstructive disease.
“We found that HIV-infected patients were more likely to have incident diagnoses of non-infectious chronic diseases including…as well as pulmonary infections”, comment the investigators.
“Fewer infectious complications and a greater frequency of non-HIV associated pulmonary disease…appears to parallel the greater burden of chronic, non-infectious comorbid diseases afflicting many aging HIV-infected patients”, they add.
The investigators suggest that HIV specialists should be mindful of their findings when providing care to their patients.
Crothers K et al. HIV infection and the risk of pulmonary diseases in the combination antiretroviral therapy era. American Journal of Respiratory and Critical Care Medicine, online edition, DOI 10.1164/rccm.201006-0836OC, 2010 (for free abstract and for-fee access to full-text click here)