Statins increase the risk of pneumonia and other infections

Researchers say that when doctors use statins to treat diseases in the vast Texas community, pneumonia is more common in the patient population. The community here is served by the military health system. This finding is contrary to the previous observational research that statins can prevent pneumonia and other infections. It was revealed in a retrospective study of active military personnel and their families near the San Antonio area. And it was reported in the journal by KellyDaniels, a pharmacy doctor at the University of Texas.
     It is well known that statins have anti-inflammatory effects, but the mechanism by which they reduce infection is unclear. In his report at the Interdisciplinary Meeting on Antimicrobial Drugs and Chemotherapy, Daniels also pointed out that the protective effects of statins have not been confirmed in prospective randomized trials. In the current study, Daniels and his colleagues tried to test the hypothetical effect among populations who are served by the San Antonio Military Market, a medical institution that provides services to active military personnel and their spouses and children.
     They analyzed nearly 68,000 people from 2003 to 2005 who had at least one healthcare service and one prescription for statins, and they also used subsequent case files for these people in 2009. During the four-year follow-up, the researchers searched for ICD-9 codes consistent with pneumonia and bacterial bloodstream infection. Their study population included 14,821 individuals who had received at least one statin treatment for 3 months during the baseline period and 52,787 individuals who had not taken statins during the baseline and follow-up period. Contrary to the expectations of the researchers, the infection rate of statin users for these two types of infections during the follow-up period was much higher than that of those who did not take statins. The proportion of patients diagnosed with pneumonia was 12.4% vs 5% of statin users compared with non-statin users. In the proportion of patients diagnosed with bacteremia, statin users were 1.5% vs 0.4% compared with non-statin users.
     However, statin users are very different from non-statin users in some ways that can lead to the risk of infection. The age of statin users is significantly older, and the average age ratio of non-statin users is 66 vs 43, the average Charlson complication index ratio is 3.4 vs 0.7, and P<0.0001 for the two groups. Most individual complication rates are more common among statin users. For example, 5.8% of statin users are found to have congestive heart failure, compared to 0.4% of non-statin users. So when Daniels and his colleagues adjusted for these differences—taking into account age, gender, comprehensive Charlson score, and frequency of patient conditions—the disparity in the prevalence of pneumonia and bacteremia was narrowed.
     In fact, in terms of bacteremia, there was no difference between the two groups, and there was an adjusted relative risk of 1.00 accompanying statin use (95% CI 0.78-1.27). Despite this, statin use remains a significant risk factor for pneumonia (adjusted RR value 1.15, 95% CI 1.06--1.25).
     According to the investigator, although the scope of impact is small, it is precisely because it contradicts previous studies that statin users have a low risk of pneumonia. This finding provides theoretical support for further exploration. Daniels told the MedPage Today health information website that some data for this study that may reveal problems is not yet available, such as patients' smoking status and alcohol consumption. In this study, the researchers did not explain the duration of statin use.