Higher STD rates among users of erectile dysfunction drugs

"Anyone who does not practice safer sex, no matter their age, can contract an STD," says Anupam B. Jena, MD, PhD, of the Massachusetts General Hospital (MGH) Department of Medicine, the study's lead author. "Even though STDs are quite rare among older men -- on the order of 1 per 1,000 individuals -- we found that STD rates in men who used ED drugs were two to three times higher, both before and after they filled their first prescription."

Jena and his co-authors note that ED drugs have become popular since sildenafil (Viagra) was first introduced in 1998. As early as 2002 it was estimated that up to 20 percent of U.S. men over 40 had tried an ED drug. Studies have shown both that rates of STDs, including HIV/AIDS, are rising in older individuals as well as the general public and that people over 50 are much less likely than those in their 20s to use condoms during sex or be tested for HIV infection. A survey of primary care physicians found that they rarely if ever discussed reducing sexual risk factors with middle aged or older patients.

Small studies of men who have sex with men had associated the use of ED drugs with higher-risk behaviors and increased rates of STDs. But no previous study had examined the relationship between ED drugs and STD risk in a large, representative sample of privately insured older men. For the current study, the researchers examined health insurance claims records covering 1997 though 2006 from 44 large U.S. employers. For male beneficiaries over 40 who used ED drugs, the researchers collected data covering one year before and one year after the first prescription was filled. Each ED drug user was matched with five non-users randomly selected from the database, for whom claims data covering the same two-year periods was collected.

The final study group included about 40,000 men who used ED drugs and nearly 1.37 million who did not. In both the year before and the year after the first ED drug prescription, users had significantly higher rates of STDs than non-users did in matching time periods. HIV/AIDS was the most frequently reported STD in both groups, followed by chlamydia. Since the prevalence of STDs did not markedly change after ED drug therapy began, the authors note that the difference between groups probably reflects higher-risk sexual practices among users of the drugs. The data gathered could not indicate whether ED drug use itself increased STD risk, but the authors are investigating that question in a further study.

"Health care providers need to recognize that their older adult patients who are on ED drugs are already at a higher risk of having or acquiring an STD," says Dana Goldman, PhD, director of the Schaeffer Center for Health Policy and Economics at the University of Southern California (USC), the study's senior author. "Both the physicians who prescribe these drugs and the pharmacists who fill those prescriptions should counsel all patients on the importance of safer sexual practices."

Co-authors of the Annals of Internal Medicine report are Amee Kamdar, PhD, University of Chicago; Darius Lakdawalla, PhD, Schaeffer Center at USC; and Yang Lu, PhD, RAND Corporation. The study was supported by grants from the RAND Roybal Center for Health Policy Simulation, the National Institutes of Health, the Agency for Healthcare Research and Quality, and the Bing Center for Health Economics.