HEALTH NEWS

Study Title:

Statins and Pneumonia

Study Abstract

Objective To test the hypothesis that hydroxymethyl glutaryl coenzyme A reductase inhibitors (statins) may decrease the risk of community acquired pneumonia.
Design Population based case-control study.

Setting Group Health, a large integrated healthcare delivery system.

Population Immunocompetent, community dwelling Group Health members aged 65 to 94; two matched controls for each case with pneumonia. Information on comorbid illnesses and functional and cognitive status, potential confounders of the association between statin use and risk of pneumonia, came from medical record review and computerised pharmacy data.

Main outcome measure Adjusted estimates of risk of pneumonia in relation to current statin use.

Results 1125 validated cases of pneumonia and 2235 matched controls were identified. Compared with controls, cases were more likely to have chronic lung and heart disease, especially severe disease, and functional or cognitive impairment. Current statin use was present in 16.1% (181/1125) of cases and 14.6% (327/2235) of controls (adjusted odds ratio 1.26, 95% confidence interval 1.01 to 1.56). Among cases admitted to hospital and matched controls, current statin use was present in 17.2% (68/395) of cases and 14.2% (112/788) of controls (adjusted odds ratio 1.61, 1.08 to 2.39, compared with non-use). In people in whom statins were indicated for secondary prevention, the adjusted odds ratio for risk of pneumonia in relation to current statin use was 1.25 (0.94 to 1.67), in those with no such indication, it was 0.81 (0.46 to 1.42).

Conclusions Statin use was not associated with decreased risk of pneumonia among immunocompetent, community dwelling older people. Findings of previous studies may reflect "healthy user" bias.

From press release:

Taking popular cholesterol-lowering statin drugs, such as Lipitor® (atorvastatin), does not lower the risk of pneumonia. That's the new finding from a study of more than 3,000 Group Health patients published online on June 16 in advance of the British Medical Journal's June 20 print issue.

"Prior research based on automated claims data had raised some hope—and maybe some hype—for statins as a way to prevent and treat infections including pneumonia," said Sascha Dublin, MD, PhD, a physician at Group Health and assistant investigator at Group Health Center for Health Studies. "But when we used medical records to get more detailed information about patients, our findings didn't support that approach."

In fact, Dublin's population-based case-control study found that pneumonia risk was, if anything, slightly higher (26%) in people using a statin than in those not using any; and this extra risk was even higher (61%) for pneumonia severe enough to require being hospitalized.

"As a doctor, I'm a fan of statins for what they've been proven to do: lowering cholesterol and risk of heart disease and stroke in people who've had either disease or are at risk for them," said Dublin. Statins are HMG coenzyme A reductase inhibitors, which also include Zocor® (simvastatin) and Mevacor® (lovastatin). This class of medications lessens inflammation, which plays a role in infections.

"But now we and some others have found that statins may have gotten some unearned credit for health benefits that they don't actually have, including preventing pneumonia," Dublin said.

Suggestions from prior research had led to calls for expensive randomized controlled trials of statins to prevent or treat infection. "But our study indicates that such trials would be an ill-advised use of limited research funds at this time," she added.

Why the discrepancy between this new study and earlier ones? "Healthy-user bias is one reason," said Dublin. In other words, compared to people who don't take statins, those who do may be healthier and have healthier habits that lower their risks of unrelated diseases such as pneumonia. And that's just what she found: Study patients who were on statins were less frail or disabled and also more likely to be vaccinated against flu or pneumococcal pneumonia. They were less likely to smoke, to have dementia, or to need help with bathing or walking.

Unlike the previous research on statins and pneumonia, Dublin's study made great efforts to control for this bias, including reviewing medical records in detail for every study subject. It confirmed that every pneumonia event was a true case of pneumonia, which prior studies rarely did. And it focused on relatively healthy elderly people. All had intact immune systems and none lived in a nursing home. She studied the same 65- to 94-year-old patients, with their records coded to protect their privacy, as in earlier Group Health research, published in The Lancet in 2008. That work showed the flu vaccine didn't protect the elderly from pneumonia as much as had been thought.

"We did an old-fashioned 'chart review,'" said Dublin. "By reading the text in the medical records, you catch crucial details."

Dublin holds a Paul B. Beeson Career Development Award from the National Institute on Aging, American Federation for Aging Research, John A. Hartford Foundation, Atlantic Philanthropies, and Starr Foundation. Group Health Center for Health Studies internal funds covered the data collection and analysis.

Study Information

Sascha Dublin, Michael L Jackson, Jennifer C Nelson, Noel S Weiss, Eric B Larson, Lisa A Jackson.
Statin use and risk of community acquired pneumonia in older people: population based case-control study.
BMJ
2009 June
Group Health Center for Health Studies, 1730 Minor Avenue, Suite 1600, Seattle WA 98101-1448, USA.