September 13, 2012 (San Francisco, California) — Statin users are more likely to develop pneumonia than people who do not use statins, according to a new study presented here at the 52nd Interscience Conference on Antimicrobial Agents and Chemotherapy.
This finding is in contrast to previous studies, which have shown that statins have "a protective effect," said Kelly R. Daniels, PharmD, a pharmacist at the University of Texas at Austin.
The fact that statins, which are widely prescribed for hyperlipidemia, inhibit inflammation and might kill microbes led the researchers to wonder if the drugs also protect against pneumonia and bacteremia.
Meta-analyses have shown that statins reduce mortality from these infections, Dr. Daniels noted. In contrast, randomized controlled trials have not shown better outcomes in statin users who contract these infections.
To shed light on the issue, Dr. Daniels and her colleagues analyzed 1482 statin users and 52,787 nonusers at a San Antonio military facility.
Statin users were defined as people who filled at least one 3-month statin prescription during the study period (October 1, 2003 to September 30, 2005).
Nonusers were defined as people who received a prescription, but not a statin, during the study period and did not receive a statin during the 4-year follow-up period (October 1, 2005 to September 30, 2009).
Not surprisingly, the 2 groups were significantly different at baseline in many respects. The statin users were older than the nonusers (mean age, 65.9 vs 42.8 years; P < .0001), and their Charlson Comorbidity Score, which takes such factors as diabetes, malignancy, and myocardial infarction into account, indicated that they were much sicker (3.4 vs 0.7).
After adjustment for these differences, the researchers found that bacteremia was more common during the follow-up period in the statin users than in the nonusers (1.5% vs 0.4%).
However, after adjustment for comorbidities in the baseline populations, the difference in bacteremia was not statistically significant (relative risk, 1.00; 95% confidence interval [CI], 0.78 to 1.27).
Pneumonia was more common during the follow-up period in the satin users than in the nonusers (12.4% vs 5.0%). After adjustment for comorbidities, the relative risk was 1.15 (95% CI, 1.06 to 1.25).
Dr. Daniels proposed several possible explanations for the difference between these results and previous study findings. "There may be some confounding variables we have not taken into consideration," she said, or statins might be more effective in treating acute infections than in preventing new ones.
One thing is clear, she said: It's too early to prescribe statins for infections.
Amélie Faudel, PharmD, a pharmacist at the South Hospital Center in Lyon, France, who was not involved in this study, agrees that the findings need a lot of sorting out. "I think more research needs to be done in this area," she told Medscape Medical News.
Dr. Faudel and Dr. Daniels have disclosed no relevant financial relationships.
52nd Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC): Abstract L1-297. Presented September 9, 2012.
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Cite this: Statins May Increase Pneumonia Risk - Medscape - Sep 13, 2012.