Cochrane for Clinicians

Putting Evidence into Practice

Effectiveness of Condoms in Reducing Heterosexual Transmission of HIV

WILLIAM E. CAYLEY, JR., M.D., M.DIV., University of Wisconsin School of Medicine, Eau Claire, Wisconsin

The Cochrane Abstract below is a summary of a review from the Cochrane Library. It is accompanied by an interpretation that will help clinicians put evidence into practice. William E. Cayley, Jr., M.D., M.Div., presents a clinical scenario and question based on the Cochrane Abstract, along with the evidence-based answer and a full critique of the abstract.

Clinical Scenario

A 25-year-old man reports having multiple female sexual partners. He asks how effective condoms are in preventing human immunodeficiency virus (HIV) infection.

Clinical Question

How effective are male condoms in reducing heterosexual HIV transmission?

Evidence-Based Answer

Evidence indicates that male condoms reduce the risk of heterosexual HIV transmission by 80 percent.

Cochrane Abstract Background. The amount of protection that condoms provide against transmission of HIV and other sexually transmitted infections is unknown. Cohort studies of sexually active, HIV-serodiscordant couples with follow-up of the seronegative partner provide a situation in which a seronegative partner has known exposure to the disease, and disease incidence can be estimated. When some persons use condoms 100 percent of the time and some never use condoms, condom effectiveness can be estimated by comparing the infection incidence rates. Condom effectiveness is the proportionate reduction in disease as a result of condom use. Objectives. The objective of this review is to estimate condom effectiveness in reducing heterosexual transmission of HIV. Search Strategy. The authors1 used electronic databases (AIDSLINE, CINAHL, Embase, and MEDLINE) to identify relevant studies, and reference lists were searched by hand. Selection Criteria. For inclusion, studies had to have data about sexually active, HIV-serodiscordant, heterosexual couples; a longitudinal study design; HIV status determined by serology; and contain condom usage information for a cohort of "always" (100 percent) or "never" (zero percent) condom users. Data Collection and Analysis. Studies that met the inclusion criteria were reviewed for inclusion in the analysis. Sample sizes, number of seroconversions, and person-years of disease-free exposure time were recorded for each cohort. If available, the direction of transmission in the cohort (i.e., male-to-female, female-to-male), date of study enrollment, source of infection in the index case, and presence of other sexually transmitted diseases were recorded. Duplicate reports on the same cohort and studies with incomplete or nonspecific information were excluded. HIV incidence was estimated from the cohorts of always users and never users. Effectiveness was estimated from these two incidence estimates. Primary Results. Of the 4,709 references that initially were identified, 14 were included in the final analysis. Thirteen cohorts of always users yielded a homogeneous HIV infection incidence estimate of 1.14 (95 percent confidence interval [CI], 0.56 to 2.04) per 100 person-years. Ten cohorts of never users appeared to be heterogeneous. The studies with the longest follow-up (mainly studies of partners of hemophiliac and transfusion patients) yielded an HIV incidence estimate of 5.75 (95 percent CI, 3.16 to 9.66) per 100 person-years. Overall effectiveness (i.e., the proportionate reduction in HIV seroconversion with condom use) is approximately 80 percent. Reviewers' Conclusions. This review indicates that consistent use of condoms results in an 80 percent reduction in HIV infection incidence. Consistent use is defined as using a condom for all acts of penetrative vaginal intercourse. Because the studies used in this review did not report on whether condoms were used correctly for every act of intercourse, effectiveness and not efficacy is estimated. This estimate refers to the male condom in general, not specifically to the latex condom, because studies tended not to specify the type of condom that was used. Thus, condom effectiveness in reducing HIV transmission is similar to, although lower than, that for contraception. This clinical content conforms to AAFP criteria for evidence-based continuing medical education (EB CME). EB CME is clinical content presented with practice recommendations supported by evidence that has been systematically reviewed by an AAFP-approved source. The practice recommendations in this activity are available online at http://www.cochrane.org/cochrane/revabstr/AB003255.htm. These summaries have been derived from Cochrane reviews published in the Cochrane Database of Systematic Reviews in the Cochrane Library. Their content has, as far as possible, been checked with the authors of the original reviews, but the summaries should not be regarded as an official product of the Cochrane Collaboration; minor editing changes have been made to the text (www.cochrane.org).

Practice Pointers

Programs for the prevention of HIV infection promote and measure condom use as an important element of HIV risk-reduction behavior.2-4 Some experts suggest that condoms may reduce HIV infection risk by as much as 90 percent,2 and the Centers for Disease Control and Prevention states that "latex condoms, when used consistently and correctly, are highly effective in preventing the sexual transmission of HIV...."5 Because a randomized trial to document the actual effectiveness of condoms for HIV infection prevention would be unethical, this review provides the best information available on the extent to which male condoms prevent transmission of HIV.

The review reports HIV transmission rates per 100 person-years; these results suggest that of 100 heterosexually active, HIV-serodiscordant couples who do not use condoms, there would be five to seven new cases of HIV each year, and that if those same couples always used condoms, there would be only one new case each year. Therefore, condom use appears to provide 78 to 83 percent relative reduction in the risk of heterosexual HIV transmission.

Because these data come from multiple studies and different populations, they must be interpreted with caution. The "never users" appear to have more baseline HIV infection risk factors than the "always users" and may be at higher risk for having multiple partners. Comparing them with a lower risk group of "always users" may have given an artificially high estimate of risk reduction. Although the actual magnitude of HIV infection risk reduction from condom use for heterosexual intercourse likely will vary based on other risk factors and behaviors, the best evidence to date indicates that condom use reduces the risk of heterosexual HIV transmission by approximately 80 percent. Educating patients about this 80 percent risk reduction may help them understand more clearly how effective, even though imperfect, condoms are in protection against HIV transmission.

The Author

William E. Cayley, Jr., M.D., M.Div., is assistant professor at the University of Wisconsin Eau Claire Family Practice Residency Program.

Address correspondence to William E. Cayley, Jr., M.D., M.Div., University of Wisconsin Eau Claire Family Practice Residency, 807 S. Farwell, Eau Claire, WI 54701 (e-mail: bcayley@yahoo.com). Reprints are not available from the author.

REFERENCES

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Cochrane Briefs

Drug Treatments for Patients with Dysthymia

Clinical Question

Which drug treatments for dysthymia are most effective?

Evidence-Based Answer

All antidepressants studied have similar efficacy in the treatment of patients with dysthymia. Side effect profiles vary. The largest comparisons support the use of tricyclic antidepressants and selective serotonin reuptake inhibitors (SSRIs).

Practice Pointers

Patients with dysthymia have less severe but more chronic symptoms than patients with depression. De Lima and colleagues published two systematic reviews1,2 on the treatment of dysthymia. The first review, by De Lima and Moncrieff,1 found that antidepressants are highly effective in treating dysthymia compared with placebo. Approximately four patients must be treated to achieve one response. However, it is not clear which antidepressant produces the best results.

To determine the most effective antidepressant, De Lima and Hotopf 2 searched for randomized and quasi-randomized controlled trials comparing at least two active drug treatments. Patients in these studies had dysthymia for at least two years and were studied for four to 12 weeks in psychiatric, primary care, and community settings.

Tricyclic antidepressants, SSRIs and monoamine oxidase inhibitors had similar efficacy. Imipramine was the most commonly studied tricyclic antidepressant, and fluoxetine was the most commonly studied SSRI. Only one study compared SSRIs with tricyclic antidepressants. Both drug classes had a similar effect on mood, but the SSRIs had a lower dropout rate. Therefore, medication choice should be based on the side effect profile. No data are available on optimal dosage or length of treatment.

CLARISSA KRIPKE, M.D.

REFERENCES

Optimal Dosage of Tricyclic Antidepressants

Clinical Question

What is the optimal dosage of tricyclic antidepressants in the acute phase of treatment of major depression in adults?

Evidence-Based Answer

Although the quality of the data limits the strength of the recommendation, current evidence shows that 75 to 100 mg per day of a tricyclic antidepressant is more effective than placebo. Higher dosages are not more effective and are associated with more dropouts because of side effects.

Practice Pointers

Although tricyclic antidepressants have been proved effective in the treatment of depression, there is little evidence for the optimal dosage. Despite the lack of evidence, the American Psychiatric Association recommends dosages of 100 to 300 mg per day.1

Furukawa and colleagues examined 41 trials of tricyclic antidepressants; 35 studies with 2,013 patients compared low dosages of tricyclics (75 to 100 mg per day) with placebo, and six studies with 551 participants compared low dosages of tricyclics with standard dosages (more than 100 mg per day). Most studies used amitriptyline and imipramine.

At four weeks, six to eight weeks, and three to 12 months, patients were more likely to respond to dosages of 75 to 100 mg per day than to placebo. These findings were similar for primary care patients. Standard dosages of tricyclics had a higher dropout rate because of side effects and were not more effective than low dosages.

The quality of the studies was limited by poor reporting and nonstandard diagnostic criteria, and there was significant heterogeneity between studies. Therefore, a definitive answer on the optimal dosage remains unknown. However, current evidence supports the use of low-dosage tricyclic antidepressants.

CLARISSA KRIPKE, M.D.

Furukawa T, et al. Low dosage tricyclic antidepressants for depression. Cochrane Database Syst Rev 2003;3:CD003197.

REFERENCE

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