Sexually Transmitted Diseases Among Users of Erectile Dysfunction Drugs

Abstract

Pharmacologic treatments for erectile dysfunction (ED) have gained widespread popularity among middle-aged and older males in recent years. Driven largely by the high prevalence of erectile difficulties in this population1–8, rates of sildenafil use reportedly reached 1.4% in the commercially insured population by 2002.9 This is perhaps not surprising, since nearly 40% of men aged 57 to 85 have some degree of erectile dysfunction.8 While their clinical efficacy has been well documented, little is known about the relationship between ED treatments and the prevalence of sexually transmitted diseases (STDs). In light of growing evidence for rising STD cases, including AIDS cases, at older ages10–14, ED drugs have received attention for their possible contribution to these trends.13, 14 In fact, a recent study found that widowhood in older men, but not older women, was associated with higher rates of STDs, especially after the introduction of sildenafil (Viagra) in 1998.15 Although middle-aged and older adults generally take fewer risks with their health, their decreased need for contraception may imply less than optimal safe sexual practices compared to younger populations.16 For example, prior research suggests that condom use declines with age16, 17 and, among at-risk populations, individuals older than 50 years are one sixth as likely to use condoms during sex and one-fifth as likely to have been tested for HIV compared to individuals in their twenties.18 Moreover, a survey of primary care physicians revealed that most physicians rarely or never discuss sexual risk factor reduction with their middle-age and older patients.19 These facts are particularly important in light of the emergence of ED drugs, which have improved sexual function among older adult males. Several small studies in the MSM (men who have sex with men) community have investigated the connection between pharmacologic ED treatments and STDs.20–24 In this community, ED drug use is associated with high-risk sexual behavior, such as unprotected anal sex.20–22 ED drug users also report a greater number of recent sex partners and higher rates of STDs than non-users.21–23 While the measured outcomes of these studies likely reflect selection bias among users rather than the effect of ED drugs per se, these studies nonetheless highlight a group of individuals within the MSM community who are at high risk of contracting STDs. In light of these findings and the growing use of pharmacologic treatments for ED, we investigated the relationship between STDs and ED drug use in a comprehensive, large sample of privately insured, middle-age and older adult male beneficiaries. Large datasets are required to examine STD patterns since in the general population itself, STDs are still quite rare, and even more so among middle-age and older adults.15 For men above 40, we compared STD rates between users and non-users of ED drugs, adjusting for pre-existing STDs and other co-morbidities. We also compared STD rates within users before and after initiation of an ED drug. We hypothesized that users of ED drugs would have higher rates of STDs compared to non-users and that users of ED drugs would have higher rates of STDs in the months after initiating an ED drug compared to the months prior. A confirmation of this hypothesis would suggest two things. At a minimum, men requesting ED drugs would be at higher risk of contracting or already having sexually transmitted disease and may therefore benefit from closer monitoring of risky sexual behavior and renewed discussions about safe sexual practices. Second, the availability of ED drugs could in theory directly lead to higher rates of STDs by facilitating sexual activity among those previously less sexually active.