Benefit of statins for impotence uncertain

"Statins could be a cheap and effective treatment for erectile dysfunction," reports the Daily Mail.

Sadly, for those affected by erectile dysfunction (impotence), the Mail’s claim is not supported by the evidence presented by the study.

The news is based on a relatively small study involving just 60 men with erectile dysfunction who had failed to respond to treatment with sildenafil (more commonly known as Viagra).

The study aimed to see whether treatment with a statin drug called atorvastatin (typically used to treat high cholesterol) was effective in improving erectile dysfunction compared with treatment with vitamin E or placebo.

After six weeks of treatment, men who received atorvastatin showed a significant improvement in some measures of erectile dysfunction. However, the improvement was modest and, after treatment, the erectile function of the men was not considered to be within the normal range.

In other words, the statins helped improve symptoms of erectile dysfunction, but not to such an extent that it could be considered an effective treatment.

Larger trials that assess the safety and effectiveness of atorvastatin over periods longer than six weeks are required to draw firmer conclusions about the potential benefits of this drug to treat erectile dysfunction in men who do not respond to sildenafil.

At the current time, statins are not licensed for the treatment of erectile dysfunction and cannot be recommended for this use.

Where did the story come from?

The study was carried out by researchers from Tanta University in Egypt and was funded by the same university. It was published in the peer-reviewed International Journal of Impotence Research.

The coverage of the study in the Daily Mail was accurate and appropriate, but the headline was misleading.

While the study suggests that a statin-like drug may be of some, apparently limited, benefit for men who fail to respond to sildenafil, it certainly does not show that “Statins [are a] cheap and effective treatment”.

It is also important to stress that statins should only be taken when recommended by the doctor in charge of your care. They are not safe or suitable for everyone.

What kind of research was this?

This was a blinded randomised controlled trial (RCT) comparing three interventions:

a statin drug (atorvastatin)
vitamin E
placebo

Participants in the RCT were men with erectile dysfunction who had previously received Viagra and failed to respond to treatment. While effective in many cases, a minority of men fail to respond to treatment with Viagra, often due to underlying problems with the blood vessels (endothelial dysfunction) that are connected to the penis.

What did the research involve?

Researchers recruited to their study 60 men aged between 40 and 60 years from the Sexual Health Inventory for Men (SHIM), who had all had erectile dysfunction for at least one year. To be included the men had to have previously received a drug called sildenafil (Viagra) and shown no improvement in their erectile function while taking the drug. They also had to have normal cholesterol levels. Men were excluded from the study if they had a history of cardiovascular disorders, listed in the study as either chest pain (angina) or heart attack (myocardial infarction), liver disorders, diabetes or a history of cancer.

The men were randomly split into three groups consisting of 20 men in each group and assigned to the following treatments for six weeks:

80mg atorvastatin (brand name Lipitor) daily
400 international units (IU) vitamin E daily
placebo capsules daily (control group)

Assessments were carried out before treatment, after treatment and every two weeks during treatment. The assessments included erectile function tests as well as other biochemical and blood tests.

To assess erectile dysfunction, the men were asked to answer five questions and given a score out of 25 on the International Index of Erectile Dysfunction.

This is a validated ‘checklist’ consisting of questions such as “How often were you able to get an erection during sexual activity?” and “When you attempted intercourse, how often were you able to penetrate (enter) your partner?”

The scores were then categorised into five categories – severe, moderate, mild-to-moderate, mild and no erectile dysfunction.

Erectile function was also assessed using a device called RigiScan that allows measurement of penis rigidity (hardness), duration of an induced erection and blood flow (it is an increase in blood flow that causes the penis to become erect).

What were the basic results?

After six weeks of treatment, only the group receiving atorvastatin showed a significant improvement from baseline in subjective and some objective assessments on RigiScan of erectile function.

The subjective score in the atorvastatin group increased from a baseline average of 11.75 to 18.15 after six weeks.

However, despite this improvement, none of the men in the atorvastatin group had an erectile function score within the normal range at the six-week mark (a score less than 22 was considered to indicate erectile dysfunction).

The researchers report that five people dropped out of the study, three of whom were taking atorvastatin and dropped out because of side effects (mainly severe muscle pain).

Apart from this brief explanation of people who dropped out of the study, no other information is provided about the side effects associated with taking this drug, despite the fact that the authors report that side effects were assessed fortnightly.

How did the researchers interpret the results?

The researchers conclude that atorvastatin but not vitamin E is a promising drug for men with erectile dysfunction that have not responded to treatment with sildenafil (Viagra).

Conclusion

Overall, this study provides some evidence that treatment for six weeks with atorvastatin (Lipitor) improved some measures of erectile dysfunction (but not to within the normal range) compared with vitamin E or placebo. There are some limitations to this study, some of which are described by the authors:

As this study only included men who had previously had their erectile dysfunction treated with sildenafil (Viagra) and showed no improvement, the study findings do not apply to men yet to receive drug therapy for their erectile dysfunction.
This study was of short duration (six weeks), so long-term outcomes of atorvastatin (Lipitor) to treat erectile dysfunction in men that have failed to improve on sildenafil (Viagra) are not known.
Despite the fact that the authors describe three people who dropped out of the study while taking atorvastatin “mainly due to severe muscle pain”, and the fact that side effects were assessed fortnightly, no further details about side effects are described.
More information about side effects is crucial to determining how safe the drug is when used to treat erectile dysfunction.
The authors report that a major limitation of the study was that they did not assess whether sildenafil (Viagra) was effective as a follow-up treatment for erectile function after therapy with atorvastatin (Lipitor) or vitamin E. This means that they did not test whether men were more responsive to Viagra after treatment.

Larger randomised controlled trials that assess the effects and safety of atorvastatin over longer periods are required to draw firmer conclusions about its effects on erectile dysfunction in men that have not responded to treatment with sildenafil.