Ole Kohler, MD, a psychiatrist at Aarhus (Denmark) University, presented highlights of his eye-popping population-based study of more than 872,000 Danes on an SSRI in 1997-2012, more than 113,000 of whom were on a concomitant statin. The key finding: During roughly 3 years of follow-up, the risk of contact with a psychiatric hospital for depression was 36% lower in the group on concomitant SSRI/statin therapy than in those not on a statin (Am J Psychiatry. 2016 Aug 1;173[8]:807-15).
He was quick to observe that a study such as this is vulnerable to various forms of confounding. This risk can be mitigated to a considerable extent by careful propensity score matching. Of note, however, none of the three studies that have been conducted with propensity score matching, including his own recent study of nearly 194,000 statin users and an equal number of matched nonusers, showed a difference in risk of depression between statin users and nonusers. All three studies were performed in general populations without known depression, leading Dr. Kohler to conclude that it’s unlikely that statins have a role in preventing depression in nondepressed individuals.
The focus should instead be on the possible role of statins in reducing the risk of depression in patients with cardiometabolic disease – that is, heart disease, metabolic syndrome, or type 2 diabetes – where more than a half-dozen cohort studies, including the Heart and Soul Study, have found that statins have a favorable impact, he added.
Estela Salagre, MD, a psychiatrist at the University of Barcelona, has carried out a meta-analysis of the three randomized, double-blind, placebo-controlled trials of add-on statin therapy in patients on standard therapies for moderate to severe depression published to date. She found that statin therapy was associated with a 27% greater reduction in scores on the Hamilton Depression Rating Scale, compared with placebo (J Affect Disord. 2016 Aug;200:235-42). Those findings recently were confirmed in a separate meta-analysis by other investigators using different methodologies (J Affect Disord. 2019 Oct 1;257:55-63).
However, those three randomized trials, while well conducted, have major limitations. They included only 165 participants in total, with just 6-12 weeks of follow-up. Moreover, all three RCTs were performed in one country – Iran – raising questions about their generalizability, Dr. Salagre said.