Rescreening for Gonorrhea and Chlamydial Infection Through the Mail: A Randomized Trial : Sexually Transmitted Diseases

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Rescreening for Gonorrhea and Chlamydial Infection Through the Mail

A Randomized Trial

Sparks, Rachel MPH; Helmers, Jennifer R. L. BS*†; Handsfield, H. Hunter MD*†; Totten, Patricia A. PhD; Holmes, King K. MD, PhD*; Wroblewski, Jennifer K. H. BS; Malinski, Cheryl BS*†; Golden, Matthew R. MD, MPH*†

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doi: 10.1097/01.OLQ.0000109512.95959.ED
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PERSONS TREATED FOR CHLAMYDIA trachomatis or Neisseria gonorrhoeae genital tract infections are at high risk for recurrent or persistent infections that can increase the risk of tubal scarring, ectopic pregnancy, infertility, and chronic pelvic pain. 1–7 The Centers for Disease Control and Prevention (CDC) recommends that clinicians consider rescreening all women diagnosed with chlamydial infection 3 to 4 months after treatment. 8 Past efforts to implement rescreening guidelines were largely unsuccessful, 9 in part because of the need for repeated pelvic examinations or urethral swabs to collect specimens. The introduction of nucleic acid amplification tests to detect C. trachomatis and N. gonorrhoeae in urine or from self-obtained vaginal swab specimens 10–13 has made screening for these infections more acceptable to patients 14,15 and permits mailing specimens for testing to laboratories. 16–22 We conducted a randomized trial to determine if rescreening efforts for gonorrhea and chlamydial infection in men and women treated at an urban sexually transmitted disease (STD) clinic or hospital emergency department might be more successful if patients were given the option of rescreening through the mail rather than requiring that they go to an STD clinic.

The study population was drawn from heterosexual patients 14 years of age or older diagnosed with genital C. trachomatis or N. gonorrhoeae infection at the Public Health-Seattle & King County (PHSKC) STD clinic or the Harborview Medical Center Emergency Department. The records of 344 potentially eligible patients were used to determine study eligibility. Forty-seven were excluded because of residence outside King County (n = 7), previous retesting at least 6 weeks after treatment (n = 29), ongoing incarceration or residence in a drug treatment facility (n = 3), inability to speak English (n = 3), need for rectal rescreening (n = 1), or previous study enrollment (n = 4).

We attempted to contact the remaining 297 patients by telephone or letter beginning 10 weeks after treatment. A minimum of 5 contact attempts was made to each individual. A total of 172 (58%) patients were contacted; 21 reported already having been retested, 2 were not King County residents, 1 did not speak English, and 12 reported ongoing symptoms and were advised to go to the STD clinic. Of the remaining 136, 122 (90%) enrolled in the study. Contacted patients were read a description of the study and verbal informed consent was elicited.

Eligible participants were randomized to 1 of 2 rescreening plans: 1) to go to the PHSKC STD clinic to provide a urine specimen with or without a free physical examination according to the patient’s preference (clinic rescreening), or 2) the choice of either rescreening at the STD clinic or mailing a specimen to the clinic for testing (mailing option rescreening). Women were sent a Dacron swab and polystyrene tube for a self-obtained vaginal swab. Men were sent a 30-mL tube for urine collection. Mailed kits contained instructions for specimen collection, 23 a contact telephone number, and a stamped envelope addressed for specimen return. Participants who intended to return to the clinic were instructed to request collection materials from the clinic’s front desk.

Samples were prepared according to the manufacturer’s instructions except that dry self-obtained vaginal swabs were first hydrated in 1 ml of 2-sucrose-phosphate (made in-house). All specimens were tested for C. trachomatis and N. gonorrhoeae by the CT/NG Cobas Amplicor PCR test according to the manufacturer’s instructions (Roche Diagnostics, Branchburg, NJ).

Individuals who did not return to the clinic or mail a specimen within 28 days of enrollment were recontacted. At that time, all patients were offered the option of either mailing a specimen for testing or going to the clinic.

The chi-squared test was used to assess univariate associations between categorical variables, and the t test was used to compare the means of continuous variables. The study had 80% power (α = 0.05) to detect a difference in rescreening rates for a balanced randomized sample of 120 individuals in which 50% of those randomized to mailing option rescreening and 25% of those randomized to clinic rescreening were rescreened within 28 days of enrollment.

Study procedures were approved by the University of Washington Human Subjects Committee.

Between December 2001 and October 2002, study personnel attempted to contact 297 eligible individuals, reached 172, and enrolled 122 (41%). Study subjects and potentially eligible persons not enrolled were similar in age, race/ethnicity, and gender, although study subjects were less likely to have gonorrhea (data not shown). Sixty-two participants were randomly assigned to clinic rescreening and 60 to mailing option rescreening. Although not significant, persons in the clinic rescreening group tended to be younger than those in the mailing option group (Table 1). Of the 60 subjects randomized to mailing option rescreening, 42 (70%) chose clinic retesting and 18 (30%) chose to submit a specimen through the mail; age, race, gender, and STD diagnoses did not significantly differ for those who elected to mail a specimen versus those who chose to go to the clinic.

T1-6
TABLE 1:
Characteristics of Individuals Randomized to the 2 Rescreening Plans

Figure 1 presents data on the proportion of patients rescreened within 28 and 100 days of study enrollment. Patients in the mailing option group were somewhat more likely to be rescreened within 28 days of enrollment than patients in the clinic rescreening group (45% vs. 32%; odds ratio [OR], 1.7; 95% confidence interval [CI], 0.8–3.8), although this difference was not statistically significant. Among patients randomized to mailing option rescreening, 11 (61%) of 18 who chose to mail a specimen to the clinic and 16 (38%) of 42 who stated they would go to the clinic for testing were rescreened within 28 days of enrollment (P = 0.10). Of the 42 patients randomized to clinic rescreening who did not go to the clinic to provide a specimen within 28 days of enrollment, 29 (69%) were successfully contacted a second time and offered an opportunity to be tested either at the clinic or through mailed rescreening, of whom 6 (21%) subsequently tested though the mail and 6 (21%) came to the clinic. Three patients who could not be recontacted later submitted a specimen. Of the 33 patients randomized to mailing option rescreening who were not rescreened within 28 days of enrollment, 16 (48%) were successfully contacted a second time; 2 (13%) subsequently mailed a specimen to the clinic, and 3 (19%) came to the clinic for retesting. Four patients who could not be recontacted submitted specimens after 28 days of enrollment. Thus, after both groups had been given the option of mailing a specimen to the clinic for testing, a total of 36 patients assigned to the mailing option and 35 patients assigned to clinic rescreening (60% and 56%, respectively) were rescreened (Table 2).

F1-6
Fig. 1:
Number of patients rescreened within 28 and 100 days of study enrollment.
T2-6
TABLE 2:
Rescreening Rates for Both Groups in the Randomized Trial

Patients successfully rescreened were older than those who were not rescreened (27.0 vs. 23.7, P = 0.01) but did not differ by race or gender. Individuals who were rescreened within 28 days of study enrollment (median time, 7 days; range, 0–28 days) did not differ from those rescreened later (median time, 50 days; range, 29–99 days) in terms of age, gender, race, or initial STD diagnosis. Of 38 men and 20 women with initial chlamydial infection who were rescreened, 6 men (16%) and no women retested positive for C. trachomatis (1 positive specimen was submitted through the mail). Of the 9 men and 4 women initially diagnosed with N. gonorrhoeae, 1 woman and no men retested positive.

The CDC recommends that clinicians consider rescreening all women diagnosed with a chlamydial infection 3 to 4 months after treatment. 8 Practical means to implement rescreening recommendations are needed. Submission of urine and self-obtained vaginal specimens through the mail has been found to be feasible and acceptable. 16–18,20,22 We found that although the majority of STD clinic patients preferred to return to the clinic for rescreening, many were interested in mailing specimens for testing, and most patients who agreed to mail a specimen for rescreening did so. However, only 71 (24%) of the 297 patients whom we initiated efforts to rescreen were tested, a result that is roughly comparable to another recent study of mailed rescreening that reported 63 (16%) of 399 patients were rescreened. 24 These findings highlight the persistent difficulties facing efforts to implement rescreening recommendations.

Our study had 2 important limitations. First, a large percentage of potentially eligible subjects could not be enrolled in the study, largely as a result of our inability to contact 42% of potential subjects. Although this could limit the generalizability of our findings, similar difficulties have hampered other studies of STD clinic patients, 24 highlighting the extent to which this is a barrier to program implementation more than study generalizability. Second, our sample size was inadequate to definitively compare the 2 rescreening approaches. In powering our study, we underestimated the proportion of persons in the clinic rescreening arm who would be rescreened within 28 days of enrollment and consequently had only 25% power to determine whether rescreening rates differed between the 2 groups. Despite these limitations, the increased rescreening in individuals who chose to mail a specimen suggests that this method represents a promising alternative to clinic rescreening. The effectiveness and yield of the mailed rescreening option should be evaluated in a larger, multicenter study, although future efforts will also need to incorporate other means to improve rescreening programs.

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