Chlamydia trachomatis (Ct) and Neisseria gonorrhoeae (GC) are highly prevalent in the United States,1 and are the 2 most commonly reported STDs in New York City (NYC).2 Ct and GC are largely asymptomatic, and among women, repeat infection increases risk for adverse outcomes such as pelvic inflammatory disease, chronic pain, infertility, and ectopic pregnancy.3,4 Repeat infection has been estimated to occur in 20% of STD clinic patients5 and has been attributed to inadequate management of existing partners and unprotected sex with new partners.6,7 Due to documented high repeat infection rates following treatment, the US Centers for Disease Control and Prevention (CDC) 2006 Sexually Transmitted Disease (STD) Treatment Guidelines8 recommend physicians consider retesting persons diagnosed with Ct or GC infection 3 months after treatment. CDC offers no guidance on strategies to achieve higher rates of retesting.
The New York City Department of Health and Mental Hygiene (NYC DOHMH) operates 10 public STD clinics, offering free and confidential services including HIV testing, other STD testing and treatment, hepatitis vaccinations, Pap tests, emergency contraception, patient counseling and referrals, and partner management services. All 10 clinics are served by an electronic medical record system. In 2007, 7643 cases of Ct and 2619 cases of GC were diagnosed in these clinics. Although standard clinic practice recommends that patients return for Ct/GC retesting, there is no formal retesting policy or standardized mechanism by which to achieve this. We used data from our electronic medical record system to examine the proportion of persons retesting and reinfected with Ct/GC at an NYC DOHMH STD clinic (the intervention clinic) where a retesting reminder postcard was implemented, compared to the same clinic during a preintervention period, and, for further comparison, 3 other NYC DOHMH STD clinic sites where the intervention was not performed. The intervention clinic was selected because it serves a large number of adolescent females (a key target group for Ct screening and retesting), detects a high number of Ct infections, and because the clinic staff were able and willing to accommodate a special project.
At the intervention clinic, all persons tested for Ct/GC by nucleic acid amplification test (NAAT) of urine, cervical or urethral fluid were introduced to a reminder postcard on the day of the testing visit, both by clinic staff, and through posters placed around the clinic. At several points, different clinic staff members (triage counselors, registration clerks, physicians, and public health assistants) showed patients the postcard, which featured the silhouette of an elephant, with the words “It's time to come back.” The postcard contained no information with which to determine the sender or purpose of the card once mailed. During the visit, counselors, physicians, and public health assistants each explained the importance of partner treatment, and, if positive, of retesting 3 months following treatment for Ct or GC. Patients were told that the reminder postcard would be sent to them by mail in 2½ months if that day's test indicated Ct or GC infection. All Ct or GC NAAT positive patients were mailed a reminder postcard 10 weeks after the test date.
We examined the proportion of persons with Ct or GC infection who returned for retesting and the proportion of returnees who tested positive for Ct or GC upon retesting (regardless of which of the 2 infections was initially present) in each project group (intervention group, preintervention group, nonintervention clinics group). A retesting visit was defined as a visit at which Ct/GC NAAT was performed at any DOHMH STD clinic 76 to 118 days (2.5–4 months) after treatment for the initial infection. An asymptomatic visit was a retesting visit at which neither dysuria nor discharge was reported by the patient (a subset of all retesting visits). Results were stratified by sex, race/ethnicity, and presence or absence of Ct/GC symptoms. Patient visits to the intervention clinic with lab-confirmed Ct or GC during the 1-year intervention period (April 2006 through March 2007) were compared to similar visits during a 1-year preintervention period (April 2005 through March 2006) at the same clinic, and to those during the intervention period at 3 high volume clinics which did not perform the postcard intervention (nonintervention clinics). We excluded persons not treated for their infections within 30 days of testing (5.4% of infections in all groups).
There were 1267 persons in the intervention group and 4953 in the comparison groups (1092 in the preintervention group, 3861 in the nonintervention clinics group). The intervention and preintervention groups, and 2 of the 3 nonintervention clinics were roughly comparable with regard to gender, proportion male patients who reported sex with other men (MSM), and age; one of the nonintervention clinics had a slightly older age distribution and notably larger proportion of male patients who reported sex with other men (data not shown). Two of the nonintervention clinics had a smaller proportion of patients of black non-Hispanic race/ethnicity than did the intervention clinic (due to a larger proportion of white non-Hispanic patients at one clinic, and a larger proportion of Hispanic patients at the other).
Overall, 14.1% (179/1267) of patients in the intervention group returned and retested in the retesting window (97.2% of these returnees returned to the intervention clinic), compared to 7.7% (382/4953, P < 0.0001) in the comparison groups (8.6%, 94/1092, P = 0.0001 in the preintervention group and 7.5%, 288/3861, P < 0.0001 in the nonintervention clinics). In the intervention group, 12.8% (138/1076) who did not return in the retesting window of 2.5 to 4 months did return between 4 and 6 months after the initial visit and were retested. For the comparison groups, this figure was 9.71% (439/4522).
Women were more likely to return and get retested than men (intervention: females 17.5% [84/480] vs. males 12.1% [95/787, P = 0.0071]; preintervention: females 11.1% [44/396] vs. males 7.2% [50/696, P = 0.0261]; nonintervention clinics: females 10.0% [120/1203] vs. males 6.3% [168/2658, P < 0.0001]). In the intervention group, 50.25% (90/179) of persons retesting were asymptomatic compared to 7.45% (7/94) in the preintervention group (P < 0.0001) and 23.26% (67/288) in the nonintervention clinics group (P < 0.0001). In other words, the observed increase in retesting was due almost entirely to the increase in retesting of asymptomatic persons (Fig. 1).
There was a decrease in reinfection among persons retesting during the intervention (12.3%, 22/179) compared to the preintervention period (25.5%, 24/94, P = 0.015) and compared to the nonintervention clinics (20.1%, 58/288, P = 0.05) (Table 1). Furthermore, the proportion of reinfections that were asymptomatic was higher in the intervention group (31.8%, 7/22 intervention, 4.2%, 1/24 preintervention, P = 0.01). We did not observe an increase in the total number of reinfections detected in the intervention group compared with the preintervention group (Table 1).
The CDC retesting recommendation is aimed at identifying reinfection. With a simple postcard reminder system, we increased both return visits for Ct and GC retesting and the proportion of retesting visits made by asymptomatic persons. However, the percentage of visits with reinfection was lower during the intervention, and so despite the greater proportion of persons returning, there was no increase in the number of reinfections detected. Potential explanations for these results include self-selection bias among returnees toward those less likely to be reinfected or a concurrent effect of the intervention on sexual risk behavior or partner management with consequent decrease in reinfection risk.
Our retesting strategy did increase compliance with CDC guidelines for retesting after Ct or GC infection, especially among asymptomatic persons, who are those at greatest risk for unrecognized, and therefore untreated reinfection. However, the magnitude of the effect was small, postcard printing and mailing was relatively labor-intensive, the overall proportion returning remained low, and no additional reinfections were detected. Similar interventions conducted in STD clinics in San Diego, CA and Washington, DC using a postcard reminder system also found that a low proportion of persons returned (Washington, DC: 6.6% [29/440], Bruce Furness, personal communication May 14, 2009; San Diego, CA: 9.8% [82/851], Robert Gunn, personal communication December 24, 2008). Given the small impact of the intervention, we did not adopt the postcard reminder system at the conclusion of the project; however, clinic staff will be trained to deliver routine health education messages about the importance of retesting following a Ct/GC infection.
This analysis has several limitations. The demographic differences between the nonintervention clinics and the intervention clinic may limit the validity of direct comparisons, and comparisons between a pre- and intervention period at the intervention clinic suffer from temporal trend limitations. However, the consistent results seen in the comparison groups across time interval and clinic site, we believe, strengthen the validity of the results. Although we observed increased return among persons in the intervention group, and this suggests that the card had an effect, this could have been due to increased emphasis during the clinic visit on retesting and risk of reinfection, rather than the effect of the postcard itself. We evaluated retesting and reinfection within a limited window of 2.5 to 4 months after initial treatment, which would underestimate the proportion who would return in a wider window. We are unable to compare outcomes of those in the intervention group who returned with the 85% who did not return. Although we are unable to know whether initially-infected patients retested through another provider, our electronic medical record enabled identification of retesting visits across all 10 DOHMH STD clinic sites. Finally, due to heightened confidentiality concerns for STD patients, the postcard had no return address, we put no health department or clinic information on the card, and made no mention of the reason for the card, and this could have been less effective than a more explicit reminder. We used printed address labels, and these may have had a different effect than a self-addressed postcard. It is also possible that because our intervention depended upon receipt of a mailed postcard, homeless and transient patients may not have received their reminders, and these individuals may be at highest risk for untreated reinfection due to inconsistent medical care.
Although this intervention demonstrated an improvement of minimal magnitude, it is possible that over time, and in concert with other strategies, the proportion of persons retesting could be increased further; Other investigators have examined various strategies for increasing return for retesting, including reminder phone calls, text messages, and mail-in specimens.9,10,11 Although some of the strategies resulted in a proportion retested that was higher than ours, none achieved particularly high retesting rates (generally 25%). In addition, strategies examined in a research setting which include incentives are not directly comparable to ours, which was performed as part of routine clinic practice. Future research should explore alternative means by which to comply with the CDC retesting recommendations, and should evaluate the efficacy of targeted retesting, identifying those with the greatest risk for reinfection, and, perhaps, the lowest likelihood of returning without intervention. The use of email and text message technology is promising12,13 and warrants further investigation. However, for retesting after Ct or GC infection to become routine, providers will need to introduce some sort of systematic reminder system and both patients and providers will need to think of a Ct or GC diagnosis as an indication of continued risk for infection, and as the basis for continued, rather than episodic care.
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