Prescribed opioids were associated with an increase in community-acquired pneumonia in patients with and without HIV infection, according to results of a large database study.

People living with HIV (PLWH) appeared to have a greater community-acquired pneumonia (CAP) risk at lower opioid doses and particularly with immunosuppressive opioids compared with uninfected patients, although the difference was not significant, E. Jennifer Edelman, MD, of Yale University, New Haven, Conn., and her colleagues wrote in JAMA Internal Medicine.

The researchers performed a nested case-control study comprising 25,392 participants (98.9% men; mean age, 55 years) in the Veterans Aging Cohort Study from Jan. 1, 2000, through Dec. 31, 2012.

Dr. Edelman and her colleagues compared the characteristics of 4,246 CAP cases with those of 21,146 uninfected controls in the sample. They also compared cases and controls by HIV status. They ran bivariate and multivariate analysis to estimate odds ratios for CAP risk associated with opioid exposure. In addition, the researchers ran models stratified by HIV status and formally checked for an interaction between prescribed opioid characteristics and HIV status.

In unadjusted logistic regression, prescribed opioids were associated with increased odds of CAP, with the greatest risk observed with currently prescribed opioids, compared with past prescribed opioids or no opioids.

Prescribed opioids remained associated with CAP in the adjusted models for past unknown or nonimmunosuppressive (adjusted OR, 1.24; 95% confidence interval, 1.09-1.40) and past immunosuppressive opioid use (aOR, 1.42; 95% CI, 1.21-1.67).

For currently prescribed opioids, nonimmunosuppressive or unknown, the aOR was 1.23 (95% CI, 1.03-1.48). For currently prescribed immunosuppressive opioids, the aOR was 3.18 (95% CI, 2.44-4.14).

The researchers also found evidence of a dose-response effect such that currently prescribed high-dose opioids were associated with the greatest CAP risk, followed by medium- and then by low-dose opioids, whether immunosuppressive or not.

With regard to the effect of HIV status in stratified, adjusted analyses, CAP risk tended to be greater among PLWH with current prescribed opioids, especially immunosuppressive opioids, compared with uninfected patients. However, the overall interaction term for opioid × HIV status was not significant (P = .36).

Although the researchers stated that a limitation of their study was an inability to prove causality or rule out respiratory depression (vs. immunosuppression) as the cause of the increased CAP risk, “the observed effects of opioid immunosuppressive properties and CAP risk lend support to our hypothesis that opioids have clinically relevant immunosuppressive properties.”

Dr. Edelman and her colleagues cited several limitations. For example, they were not able to determine whether patients took their prescribed medications appropriately and assess whether the patients took nonmedically prescribed opioids. Also, because men made up such a large portion of the study population, it is unclear whether the results are generalizable to women.

Nevertheless, the study “adds to growing evidence of potential medical harms associated with prescribed opioids,” they wrote.

“Health care professionals should be aware of this additional CAP risk when they prescribe opioids, and future studies should investigate the effects of opioids prescribed for longer durations and on other immune-related outcomes,” wrote Dr. Edelman and her colleagues. “Understanding whether mitigating the risk of prescribed opioids for CAP is possible by using a lower dose and nonimmunosuppressive opioids awaits further study.”

However, without such data, when prescribed opioids are warranted, physicians should attempt to modify other factors known to affect CAP risk, including smoking and lack of vaccination, Dr. Edelman and her colleagues concluded.

Several U.S. government agencies and Yale University provided funding for the study. The authors reported that they had no conflicts.

SOURCE: Edelman EJ et al. JAMA Intern Med. 2019 Jan 7. doi: 10.1001/jamainternmed.2018.6101.