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Statins May Lower Risk of non-Hodgkin Lymphoma in People With HIV
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18th Conference on Retroviruses and Opportunistic Infections, February 27-March 2, 2011, Boston
findings "indicate a potentially protective effect of statin medication [on] risk of NHL among HIV-positive patients." They suggested large prospective studies could "further clarify the association between statin use and risk of HIV-related NHL."
Mark Mascolini
Statin use appeared to protect HIV-positive people from non-Hodgkin lymphoma (NHL, an AIDS cancer), according to results of a case-control study in California's Kaiser-Permanente health system.1 The researchers warned, however, that this type of analysis cannot eliminate confounding by indication--the possibility that the reasons people get put on certain drugs may be related to the risk of future health outcomes.
Chronic inflammation caused by HIV may contribute to the risk of NHL. Hypothetically, treatment with anti-inflammatory statins could lower that risk. The Kaiser investigators also noted that some studies suggest statins have certain anticancer properties, such as arresting cell-cycle progression and inducing cell death. They planned this case-control study to test the hypothesis that statin exposure lowers the risk of NHL in people with HIV.
Cases were HIV-positive Kaiser patients with NHL diagnosed from 1996 through 2007. For each NHL case, the researchers found five HIV-positive controls without NHL, matching by age, gender, year of NHL diagnosis, race or ethnicity, and known duration of HIV infection. They classified statin therapy and nonstatin lipid-lowering therapy (fibrates, niacin, and resins) as (1) ever (at least 1 day) versus never, (2) regular versus nonregular (at least 12 months of continuous use versus fewer than 12 months), and (3) long-term versus short-term (at least 12 months of cumulative use versus fewer than 12 months).
The study included 259 cases with NHL and 1295 controls without NHL. Age in cases and controls averaged 43.1, 96% were men, and 60% were white. A lower proportion of cases than controls used statins (8.1% versus 13.7%, P = 0.01), a lower proportion of cases used statins regularly (1.2% versus 1.8%, P = 0.05), and a lower proportion of cases used long-term statins (4.3% versus 7.5%, P = 0.05). Fewer cases than controls ever used nonstatin antilipid drugs, but this difference was not statistically significant (5% versus 7.4%, P = 0.17).
Baseline CD4 count was significantly lower in people with NHL than in controls without NHL (246 versus 376, P < 0.0001). Proportions of cases and controls who used antiretrovirals before the NHL diagnosis year (25.5% versus 27.8%) and who had a clinical AIDS diagnosis before that year (12.7% versus 9.5%) did not differ significantly (P = 0.45 and P = 0.11).
Logistic regression analysis to assess the impact of statin use on NHL risk considered the case-control matching factors plus use of nonstatin antilipid drugs, history of HBV or HCV, diabetes, obesity, prior combined antiretroviral therapy, and CD4 count at NHL diagnosis. Statin use and statin duration lowered the risk of NHL at the following hazard ratios (HR) (and 95% confidence intervals):
-- Ever using statins lowered risk about 50%: HR 0.49 (0.28 to 0.84), P = 0.01
-- 12 or more months of continuous use lowered risk 50%: HR 0.50 (0.28 to 0.88), P = 0.01
-- 12 or more months of cumulative use lowered risk 60%: HR 0.40 (0.18 to 0.86), P = 0.02
-- Each month of use lowered risk 2%: HR 0.98 (0.96 to 1.00), P = 0.01
Use of nonstatin lipid-lowering drugs also correlated inversely with NHL risk, but none of those correlations reached statistical significance.
The Kaiser team noted that potential confounding by indication (explained above) and the small sample size of some subgroups limit their study. Still, they proposed that their findings "indicate a potentially protective effect of statin medication [on] risk of NHL among HIV-positive patients." They suggested large prospective studies could "further clarify the association between statin use and risk of HIV-related NHL."
Even if further work supports the protective effect of statins on NHL, it seems unlikely that statins would be prescribed solely for that purpose. But many people with HIV already take statins because of high lipids, and some researchers have proposed that controlling residual inflammation in people responding to antiretroviral therapy could stall emergence of other inflammation-driven diseases in people with HIV.
Reference
1. Chao C, Xu L, Abrams D, et al. Statin use and risk of non-Hodgkin's lymphoma in HIV-infected persons. 18th Conference on Retroviruses and Opportunistic Infections. February 27-March 2, 2011. Boston. Abstract 869.
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