as 4.6 months. The longest was reported by Xu et al. as 10.9 months.15 The remaining two studies by Niccolai et al.25 and Burstein et al.17 reported median time to reinfection as 5.2 months and 6 months, respectively. GENDER-SPECIFIC PREVALENCE AND INCIDENCE RATES Limited information was available on gender-specific reinfection rates. Over half of the studies excluded males. Of the five studies that included both sexes, three analyzed rates stratified by sex. Burstein et al. studied adolescents aged 12-19 to determine screening practices within the Kaiser Permanente Mid-Atlantic States (KPMAS) system and the positive chlamydia results from those screenings, reviewing medical histories of adolescents who were screened at least twice. 17 Researchers reported a chlamydia reinfection prevalence rate of 17.1% and 11.1% among females and males, respectively.17 Only 1.5% of the males in the KPMAS system were screened for chlamydia.17 Orr et al. reported a female reinfection prevalence rate of 73% by 7 months and a male reinfection rate of 60% by 7 months among high-risk adolescents aged 14-21 from STD clinics.16 Finally, Michelson et al., who recruited lab confirmed chlamydia from a county health department, reported reinfection incidence rates of 3,982 female cases and 2,223 male cases per 100,000 person years.14 Researchers did not include asymptomatic men in their analysis, limiting the population pool.14 Reitmeijer et al. included both genders but did not stratify reinfection by age.20 Anshuetz et al. evaluated only adolescents, but did not stratify reinfection rate by gender.28
This may mean conducting more studies with long follow-up times, either prospectively or retrospectively (i.e. surveillance data or medical history databases). The short follow-up times found in two studies could have led to inaccurate representations of reinfection rates.18,22 A reoccurring limitation cited within studies was that investigators were not certain on whether participants’ medical histories were complete. Participants could conceivably be screened and treated at clinics not affiliated with the studies. If patients were tested elsewhere, researchers would be unaware of the results due to lack of record sharing. Unexpectedly, only about half of the reviewed studies included a case definition of reinfection. Lack of universal definition negatively impacted interpretation of prevalence rate and comparison of results between studies. Additionally, improper definitions could lead to misclassification bias. There were a number of limitations to this review. It was difficult to interpret results due to methodological concerns, namely attrition rates, homogenous populations, incomplete sexual/medical histories, and inadequate follow-up times and intervals, which also influenced validity and generalizability of results. Despite the University of Pittsburgh’s comprehensive access to a number of databases and journals, not all eligible papers could be accessed. Finally, as a novice reviewer, lack of experience and limited outside help may have led to some pertinent studies being missed. There are often inherent biases associated with conducting a literature review, particularly when excluding studies based on reading abstracts and whole articles. There was a chance that despite attempting to do so, this literature review was not conducted in a wholly objective manner. Screening is an important tool that must be utilized, especially with male adolescents, who were underrepresented based on this literature review. The array of risk factors presented in this literature review suggested that populations at-risk may not be immediately determined from
APPENDIX A: SUPPLEMENTAL ON THE LITERATURE Reference Objective Population Study Design Disease Incidence or Prevalence Reinfection Results Limitations Mosure et al. [12] Determine rates and predictors of chlamydia reinfection 15-19 year old females; Family planning clinics in region Retrospective cohort. Medical database review. Prevalence = 22% 18.0% Majority did not make second visit; history of STI not in analysis; could have been tested at planning clinics Oh et al. [13] Determine incidence and risk of gonorrhea/chlamydia reinfection among adolescent females Sexually active females 11-19 years old; Adolescent clinics of Dvision of Adolescent Medicine Southeastern U.S. Prospective cohort. Analysis on subjects with at 2 visits Overall incidence = 15% Gonorrhea = 11.6% Chlamydia = 23.2% 25.3% Overall; 40% Gonorrha; 18% Chlamydia Intervals between rescreening not uniform; high attrition rates; small sample size; not generalizable; does not include history of STDs in analysis Michelson et al. [14] Describe demographics, risk, and geographical distribution of chlamydia infections Lab confirmed chlamydia tests sent to STEP County Health Department Retrosective cohort. Review of test results. Incidence = 563 infections per 100,000 13.0% Cases reported dependent on site of diagnosis; excluded asymptomatic males; excluded those who did not seek treatment Xu et al. [15] Use registry to analyze frequency and predictors of repeat chlamydial infection in women Women 10-44 years old; Initial positive test during study period Retrospective cohort. Medical database review. N/A 20.2% may have moved out of state; non-universal screening; reporting
Table 3 Continued Reference Objective Population Study Design Disease Incidence or Prevalence Reinfection Results Limitations Orr et al. [16] Compare of subsequent and reinfection of chlamydia and gonorrhea in adolescnts Ages 14-21; STD clinic and 3 urban adolescent community clinics; Positive for gc/ct Prospective cohort. STI screening. N/A 60% men 73% women Testing variability; high attrition rates especially among men Burstein et al. [17] Determine screening practices and resulting positive test results Adolescents Enrolled in KMPAS health plan; At least 1 positive ct test Retrospective cohort. Medical review. Incidence = 14.6% 16.4% Only 1.5% males in system tested; no race, SES, behavior, sexual activity available; variability in testing among sites; screening outside KMPAS system Whittington et al [18] Identify factors associated with persistent and recurrent chlamydial infection in young women Females 14-34; Reproductive medicine clinics in 5 cities; Positive ct result Prospective cohort. Interviews and ct screening N/A 7.9% High attrition; short follow-up period; variability of follow-up intervals; variability in testing; recall bias; confounding from couseling; insufficient power; not generalizable Kissinger et al. [19] Determine if age of partner influences chlamydia reinfection Women 14-30 years old; Initial ct positive at public family planning/STD clinic in 5 cities Prospective cohort. Ct screening interim behavior history. N/A 13.8% Insufficient power; not generalizable; high attrition; recall bias Rietmeijer et al. [20] Study incidence and repeat infection among clients of STD clinic Client of an STD clinic; Screened for ct more than once 30 days apart Retrospective cohort. Medical database review. Incidence = 26.1% 22.8% Not generalizable; influence of asymptomatic chlamydia; history of STI not included; high attrition; screening from outside provider
Table 3 Continued Reference Objective Population Study Design Disease Incidence or Prevalence Reinfection Results Limitations Niccolai et. al [21] Determine relationship between knowing your partner has been treated for past STI and current infection Sexually active women; 14-19 years old; 50% pregnant; history of STI Prospective cohort. Interviews and ct/gc screening. Not provided 17.5% Unsure of infection origins; recall bias; small sample size. Ellen et al. [22] Examine risk for repeat infections with reducing number of sexual partners among men Men 13-25 from screening project; Asymptomatic; 2 U.S cities Prospective cohort. Interviews and ct/gc screening N/A 6.5% Small sample size; limited power; low acceptance rate; short follow-up Magnus et al. [23] Determine if older sexual partners associated with recurrent chlamydia among adolescent women Females Infected with ct Subanalysis of parent RCT N/A 16.1% Selection bias; short follow-up; recall bias; not generalizable; unable to link 19.9% of partners Champion et al [24] Evaluate rate of reinfection stratified by history of abuse 14-45 year old women Subanalysis of parent RCT Not provided 59.4% abused 43.3% unabused Recall bias; limited power in some risk categories Niccolai et. al [25] Determine frequency and patterns of chlamydia among adolescent women 14-19 year old females; 10 public health clinics Prospective cohort. Interviews, medical record review, ct screening, review of health department reports. Prevalence = 52.6% 56.9% Did not confirm STI history; did not confirm treatment; do not know if screened between follow-ups