Population-Based Outreach for Chlamydia Screening in Men: Results From a Randomized Trial : Sexually Transmitted Diseases

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Population-Based Outreach for Chlamydia Screening in Men: Results From a Randomized Trial

Scholes, Delia PhD*; Heidrich, Fred E. MD, MPH; Yarbro, Patricia MSW*; Lindenbaum, Jeff E. MD; Marrazzo, Jeanne M. MD, MPH

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doi: 10.1097/OLQ.0b013e31805ba860
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FAILURE TO DETECT AND TREAT genital Chlamydia trachomatis (CT) infections can lead to a number of serious and costly sequelae, including pelvic inflammatory disease, ectopic pregnancy, tubal infertility, and chronic pelvic pain in women, and urethritis, epididymitis and proctitis in men.1

Since the great majority of these infections are asymptomatic, screening strategies are key to successful prevention and control measures. Most screening efforts have targeted young sexually active women, in whom prevalence is highest and consequences most severe. The epidemiology of CT infection in men has received less investigation, but in some populations the prevalence of infection in young males also may be high.2–4 However, unlike young women, generally healthy at-risk young men may access health care infrequently, and thus have less opportunity to receive testing for this common infection. We conducted a population-based randomized trial to evaluate the feasibility and efficacy of 2 outreach strategies to improve CT testing rates in young adult men.

Materials and Methods

This study was conducted at Group Health Cooperative (GH), a large mixed-model managed care plan in Washington State. Between November 2001 and October 2002, we selected all male GH enrollees ages 21–25 (n = 8820). The study population was allocated randomly to 3 arms: Arm 1 (n = 2940) received an invitation letter to be tested for CT and a preaddressed, stamped return card to request a urine home sampling kit; arm 2 (n = 2940) received a mailed invitation letter along with a home sampling kit; and arm 3 (n = 2940), the control group, received usual clinical care (no intervention, but usual access to GH clinics). In addition to the letter of invitation, the home sampling kits sent to the intervention groups included a brief risk survey, a participant information form, a brochure, a specimen bottle with instructions for collection of first-catch urine (first 10–30 cc of voided urine) and a prepaid return mailer. One reminder letter was sent to both intervention groups, 3–4 weeks after the initial mailing. Aside from free testing and no office visit copayments, there were no additional financial incentives. All study procedures were reviewed and approved by the Group Health Human Subjects Committee.

Mailed specimens returned by intervention group members were analyzed using the ligase chain reaction assay (LCx LCR, Abbott Laboratories, Abbott Park, IL). Participants in the usual care control group who were tested as part of a GH clinic visit received urethral swab testing via either ELISA (VIDAS, bioMerieux Vitek, Hazelwood, MO) (November 2001–February 2002) or unamplified DNA probe (PACE2, GenProbe, San Diego, CA) (February 2002–2003). All tests were performed according to manufacturers' specifications.

Test results were mailed to all intervention arm respondents. Subjects in the intervention arms with positive tests were contacted by telephone by the study nurse or primary care provider. When contacted, each subject was provided with treatment options (a phoned prescription to the GH pharmacy of his choice or follow-up with his own primary care provider), counseling on risk reduction, and assistance with partner notification The subject's primary care provider was also notified of the results. All CT positive subjects were successfully contacted and received standard treatment.

For the control group, arm 3, the health plan automated records were used to identify those who received in-clinic testing during the follow-up interval and to identify positive test results. For the 2 intervention arms, information on in-clinic testing (which may have occurred in addition to tests that were mailed back) was also obtained in the same manner.

The study's primary outcome, the rate of CT testing, was evaluated 4 months postrandomization using an intent to treat analysis. The relative risk of being tested was calculated by dividing the CT testing rate in each intervention group (arms 1 or 2) by the CT testing rate in the control group (arm 3). The 95% confidence intervals (95% CI) for each risk estimate were also calculated.


From the automated data available for all 3 arms, mean age was 22.6, 22.5 and 22.5 years for arms 1, 2 and 3, respectively. Intervention respondents, that is, those who provided mailed samples, were slightly older (mean age 22.7).

Mailed-back specimen kits were received from 105 of the 2940 men in arm 1 (3.6%), and 230 of the 2940 men in arm 2 (7.8%) (Table 1). Survey data from these 335 respondents found that all were sexually experienced, 78.4% were white, 20% reported a prior STD, 43% reported >2 sex partners in the previous year and 47% had not used a condom at last intercourse. Eighty percent of intervention respondents reported no genitourinary symptoms. An additional 25 and 19 men in arms 1 and 2, respectively, received testing at a GH clinic during follow-up (Table 1). For the mailed-back specimens, CT prevalence was 1 of 105 (1.0%; 95% CI, 0.1–5.1) in arm 1 and 6 of 230 (2.6%; 95% CI, 1.0–5.2) in arm 2. Among men who sought care at GH clinics and who were tested, CT prevalences were 0 of 25 (arm 1), 3 of 19 (15.8%; 95% CI, 3.4–39.5) (arm 2) and 4 of 24 (16.7%; 95% CI, 4.8–37.3) (arm 3). Since the health plan does not have a practice guideline or a standard policy of screening asymptomatic men for CT and since clinic tests were not urine-based, it is likely that most of the clinic-based testing occurred among enrollees presenting with relevant symptoms. All CT-positive participants were reached for treatment, STD counseling and partner referral.

Chlamydia Testing and Prevalence by Study Group During the 4-Month Follow-Up

Twenty-four (0.8%) men in the control group (arm 3) received testing. The relative risk of being tested, relative to controls, was 5.6 (95% confidence interval (CI), 3.6–8.7) for arm 1 and 11.1 (95% CI, 7.3–16.9) for arm 2 (Table 2). Direct mailing of the sampling kit performed best; for arm 2 versus arm 1, the relative risk of being tested was 2.3 (95% CI, 1.8–2.9).

Relative Risk of Chlamydia Testing by Study Group

We could not formally assess participants' attitudes toward these outreach approaches, but respondents provided few comments on their surveys. The study staff recorded approximately 10 negative comments from nonparticipants, principally irritation at receiving unsolicited materials in the mail on this topic. These were more numerous and more negative than nonparticipant comments for most studies conducted in the health plan, but the sample size also was large and included men from the entire health plan (throughout Washington State and Idaho).


Given health care utilization patterns of young at-risk men in the United States, screening strategies outside of conventional clinic settings merit consideration for a largely asymptomatic infection such as CT.5,6 The current population-based study found that outreach to men resulted in significantly higher rates of CT testing than occurred in usual clinic-based care, and that direct mailing of the specimen kit yielded significantly higher testing rates than a test-request approach. Respondents to the mailed interventions reported risk factors for CT acquisition or transmission, and all CT-positive intervention participants were reached for treatment and counseling. CT prevalence was lower in our study population than in a recent Danish trial,2 but similar to prevalences in other reports3,7,8,10,12 and to the 1% prevalence recently reported for Seattle.13

Strengths of the current study include the “real world” setting (no incentives and low-intensity reminders) from a US population and use of population-based strategies that are generalizable to a variety of US health care settings. The outreach strategies improved testing uptake and removed access barriers such as office visit copays, discomfort, clinic visit logistics and staff time. They were relatively inexpensive to implement (estimated $0.75US in labor and materials for the test-request packet and <$3.00US for the mailed sampling kits). In arms 1 and 2, 70% of positive CT results were discovered as a result of the intervention. Compared with those of a population-based trial in Denmark employing similar intervention strategies and follow-up,2 our results are consistent in finding that both intervention arms demonstrated notably improved testing rates over usual care, and that the best results for men were achieved by mailing the kits directly.

Despite these promising results, another important finding was the low uptake of the testing offer (5.7% overall). This response was considerably lower than in other population-based reports on mailed approaches.2–4,8–11 In the Danish study,2 for example, 15.1% of men in the test-request arm and 25.3% of those receiving direct mailed kits provided specimens, even with no reminders. The majority of reports to date have evaluated outreach in countries with some form of national health care coverage. Populations in such settings may be more likely to respond to outreach approaches; also there may be greater public awareness of CT infections and/or higher prevalences, different healthcare utilization patterns among young men or higher proportions of men who perceive themselves to be at risk for CT. In the United States, even in insured populations such as this study setting, young men are seldom targeted for preventive care campaigns—particularly in the area of STD prevention. Unfortunately, we were not able to survey our nonresponders to learn more about their risk status, reasons for nonparticipation or for measures that may have enhanced participation.

To our knowledge, this is among the first population-based evaluations of mailed outreach screening strategies undertaken in the United States.5 While these approaches resulted in notably higher testing rates relative to usual care, the low response rate means that—at a minimum—further targeting of high-risk groups would be needed to bring about reduced plan-wide CT infection rates.14 Potential subgroups to target could include men with recent infection (repeat testing) or men in at-risk age brackets residing in higher prevalence areas served by Group Health. A newly implemented health risk assessment could also be used to target higher-risk men for outreach. Small incentives, strategies to increase recognition of risk and more aggressive follow-up to mailed outreach could potentially increase response rates, but would increase costs, as well.6,7,9,15 Given the limited prevention resources in the United States, our results suggest that these approaches be carefully balanced against continued attention to testing of women: despite the stronger evidence base for screening efficacy, many US women still are not screened for this widespread and potentially damaging infection.16


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