Repeat Neisseria gonorrhea infections: A retrospective population-based analysis, 1999 - 2004 M Javanbakht, S Guerry, LV Smith, P Kerndt County of Los Angeles Department of Health Services Public Health SEXUALLY TRANSMITTED DISEASE PROGRAM

Disease Burden Gonorrhea infections cause substantial morbidity The 2nd most common reported notifiable disease Over 330,000 cases reported to CDC in 2004 Estimated annual incidence of 718,000 cases Although gonorrhea rates have declined dramatically since 1975 attributed in part to: Widespread screening of women starting in 1972 And resulting treatment of asymptomatic persons and their sexual partners Hyperendemic areas persist, particularly in urban areas In addition, recent increases in certain areas

Reasons for Hyperendemicity Increased rates and areas of hyperendemicity are most likely driven by: High-risk individual (“core-transmitters”) Gonorrhea reinfections account for as much as half of reported morbidity Further complicating the issue: Gonorrhea screening guidelines are vague Most providers/programs use chlamydia screening guidelines as the basis for gonorrhea testing Health department initiated partner referral and treatment are generally not offered because of limited resources and large disease burden

Significance of Reinfections Consequently, in areas of high morbidity, especially areas experiencing increases in gonorrhea rates, there is a critical need for: Estimation of reinfection rates Understanding of epidemiology of reinfection Which in turn can help to guide Screening guidelines Direct prevention efforts, especially in terms of partner referral and treatment

Objective To examine the incidence and time to repeat gonorrhea infection among a representative population To assess factors associated with repeat gonorrhea infections

Study Overview Retrospective cohort study Among reported gonorrhea cases in Los Angeles County Information collected on: Demographics Treatment information Subsequent reported infections Follow-up information collected for 5-years

Study Setting Cohort based on reportable STD registry in Los Angeles County, which: Comprises a geographic area of over 4,000 square miles Home to ~10 million residents Hispanics comprise the single largest racial/ethnic group (45%), followed by Whites (31%) 70% have at least a high school education 18% of population below poverty line High rates of gonorrhea Overall rate of 103 per 100,000 Highest rates among African American men (702 per 100,000) Healthy People 2010 goal = 19 per 100,000

Study Design Retrospective study conducted by constructing a cohort of patients from the Los Angeles County reportable STD registry Inclusion criteria: Initial treated infection reported between 1999 and 2000 Follow-up information collected through 2004, including information on: Demographics: age, race/ethnicity, area of residence Clinical information: presence of symptoms, clinic type, treatment information, subsequent reported gonorrhea infections

Statistical Analysis Outcome – repeat gonorrhea infection, defined as: infection detected > 30 days after treatment for preceding infection Risk estimation was conducted using Kaplan-Meier (product-limit) method Factors associated with repeat infection were evaluated using Cox proportional hazards regression

The Cohort Between January 1, 1999 and December 31, 2000, a total of 12,323 unique cases of gonorrhea were reported in Los Angeles County Among this group, 7,591 (62%) were eligible and included in the study

Baseline Demographic Characteristics Male Female 40+ 30-39 20-29 15-19 < 15 Other Unknown Hispanic African American White

Gonorrhea Reinfections Among the 7,591 who were eligible and included in the study: 1,300 (17%) experienced > 1 gonorrhea reinfection over 5-years Median number of reinfections 1 (range 1 – 7) 77% (n=995) with only 1-reinfection 16% (n=209) with 2-reinfections 7% (n=105) with > 3-reinfections Resulting in 1,756 reinfections

Time to development of gonorrhea reinfection Median time to reinfection = 13 months

Incidence of Gonorrhea Reinfection by Demographics Female Male Other White Hispanic African American

Incidence of Gonorrhea Reinfection by Age 35+ 30-34 25-29 20-24 15-19 < 15

Factors associated with gonorrhea reinfection Adjusted HR* (95% CI) P value Gender Male 1.59 (1.40 – 1.80) <.0001 Female Reference Age < 15 2.62 (1.80 – 3.80) 15 – 19 1.57 (1.33 – 1.85) 20 – 24 1.21 (1.03 – 1.41) 0.0178 25 – 29 1.36 (1.15 – 1.61) 0.0004 30 – 35 1.16 (0.97 – 1.41) 0.1117 35+ *HR = Hazard Ratio; adjusting for age, gender, race, clinic type, and symptom status

Factors associated with gonorrhea reinfection Adjusted HR* (95% CI) P value Race/Ethnicity African American 1.82 (1.56 – 2.12) <.0001 White 2.04 (1.69 – 2.47) Other 1.30 (0.77 – 2.19) 0.3251 Hispanic Reference Clinic type Public 1.20 (1.06 – 1.35) 0.0034 Jail/Corrections 0.88 (0.68 – 1.16) 0.3707 0.64 (0.40 – 1.03) 0.0689 Private *HR = Hazard Ratio; adjusting for age, gender, race, clinic type, and symptom status

Factors associated with gonorrhea reinfection among men Adjusted HR* (95% CI) P value Age < 15 0.95 (0.32 – 2.86) 0.9283 15 – 19 1.23 (1.00 – 1.53) 0.0546 20 – 24 1.10 (0.93 – 1.30) 0.2464 25 – 29 1.39 (1.80 – 1.64) <.0001 30 – 35 1.16 (0.97 – 1.40) 0.1105 35+ Reference Race/Ethnicity African American 1.52 (1.28 – 1.80) White 1.89 (1.58 – 2.28) Other 0.97 (0.58 – 1.61) 0.9037 Hispanic *HR = Hazard Ratio; adjusting for age, race, and clinic type

Factors associated with gonorrhea reinfection among women Adjusted HR* (95% CI) P value Age < 15 7.11 (3.58 – 14.13) <.0001 15 – 19 4.31 (2.36 – 7.88) 20 – 24 3.20 (1.74 – 5.90) 0.0002 25 – 29 2.09 (1.05 – 4.16) 0.0363 30 – 35 1.42 (0.63 – 3.20) 0.3973 35+ Reference Race/Ethnicity African American 2.87 (2.13 – 3.85) White 0.93 (0.47 – 1.82) 0.8320 Other 2.27 (0.82 – 6.35) 0.1165 Hispanic *HR = Hazard Ratio; adjusting for age, race, and symptom status

Limitations Data based on a passive surveillance system, consequently: Rate of repeat infections underestimated because of under-reporting Limited information, especially in term of sexual behaviors Predictors maybe marker of greater screening/reporting However, strengths of this project include: Large number of cases from a population-based surveillance system Ability to link gonorrhea infections in each individual regardless of where they sought care

Discussion Findings from this study suggest that: Repeat gonorrhea infections are common Overall, the greatest risk of repeat infection among: Men, as well as African Americans and Whites, and those less than 30 However, factors predictive of repeat infection different by gender Among men those aged 25-29 as well as African Americans and Whites at greatest risk Among women those in the youngest age groups and African Americans are at the greatest risk

Implications Screening efforts should be targeted to those at highest risk and different by gender Furthermore, frequent screening needs to be accompanied by enhanced efforts to treat cases as well as enhanced partner referral and treatment services

Marjan Javanbakht, MPH, PhD mjavanbakht@ladhs.org (213) 744-5926 SEXUALLY TRANSMITTED DISEASE PROGRAM