The tragedy of congenital syphilis (CS) is that with proper prenatal screening and adequate and timely treatment of pregnant women with syphilis, the disease is preventable in nearly every case.1 Nonetheless, CS remains a present and devastating disease of the neonatal and early childhood periods. The national CS rates have been rising. In 2007, the country experienced a 15% increase in the rate of CS (9.1–10.5 cases per 100,000 live births).2 At the state level, Arizona has had one of the top 5 highest annual rates of CS 5 of 6 years during 2002–2007, including the highest rate in the country during the years 2003, 2004, and 2005.2–7
Between 2005 and 2006, the number of reported CS cases in Arizona decreased from 28 to 16 cases, representing a 43% decrease.6,7 The number then increased in 2007 to its previously elevated levels with 30 cases.2 To identify any unreported CS cases for the 2006 year, we cross-matched the state infant registries with the Arizona Department of Health Services (ADHS) sexually transmitted diseases (STD) database.
In Arizona, physicians and laboratories are mandated by state rule to report certain STDs to ADHS.8 A cross-match was performed of all women reported to ADHS with positive syphilis-related laboratory tests (treponemal and nontreponemal) from January 1, 2005 to December 31, 2007 with the 2006 Arizona live birth and fetal death registries. The first name, date of birth, and/or last name of women with positive syphilis labs in the STD database were cross-matched to the live birth database and fetal death database using maternal first name combined with either maternal last name, maiden name, date of birth, or fetal last name (Fig. 1). The cross matches were completed using Statistical Analysis Software version 9.1 and managed in Microsoft Excel 2003. This study methodology was based upon similar methods published from the New Mexico State Health Department.9 Disease surveillance, data collection, evaluation, and analysis are ongoing public health surveillance activities and thus are not subject to review by institutional review boards.
Criteria for classification of CS cases were determined using the CDC Congenital Syphilis Cases Investigation and Report Form 73.126 and previously published criteria (1) a live born infant with signs of CS or in whom Treponema pallidum was identified from external lesions, placenta, umbilical cord, or autopsy specimens, or whose mother had a syphilitic lesion at delivery; (2) a live born infant delivered to a woman with untreated or inadequately treated syphilis before or during pregnancy; (3) a live born infant delivered to a woman with early syphilis whose serologic response to penicillin therapy was documented to be inadequate and who had either a radiologic and/or cerebrospinal fluid test consistent with CS (or the infant tests were not completed); or (4) a stillborn infant delivered to a woman with untreated or inadequately treated syphilis before or during pregnancy.10–12 In addition, any baby was included as a case if a maternal positive nontreponemal test was obtained during pregnancy or at delivery, but the positive treponemal test was completed subsequently. Categories for reason for classification of those determined to be cases were assigned according to a previously published analysis from Arizona: treatment less than 30 days before delivery, lack of adequate titer decline, no treatment during pregnancy, and no prenatal test with a positive test at delivery.13
After cross-matching of the datasets, the final list of women with positive syphilis lab tests with matched live births or fetal deaths in 2006 was then evaluated on a case by case basis. All but two previously reported cases (both due to first and middle name ordering discrepancies) were identified through the cross-match. Available state and county health department field, interview, and reporting records were initially reviewed to identify infants that should be excluded from further review because their mothers were falsely positive for syphilis (positive nontreponemal with a negative treponemal test), or the previously described case criteria were not met. Possible CS cases then underwent a review of prenatal care and delivery medical charts for determination of CS case status.11 Demographic information, including maternal age, race, county of residence, and maternal stage of syphilis was collected from health department record review. Gestational age, maternal and infant treatment, and infant clinical assessment were collected from medical chart review.
After the exclusion of previously reported congenital syphilis cases, the merge of the live births and the STD database resulted in the identification of twenty eight mother-infant pairs. Four of these infants were determined to be congenital syphilis cases (Table 1). The merge of the fetal deaths database and the ADHS STD database resulted in the identification of 3 mother-infant pairs. Two of these babies were classified as syphilitic stillbirth cases (Table 1).
Arizona continues to face the challenge of high congenital syphilis rates. The use of this cross-match method led to the identification and evaluation of 6 unreported cases of congenital syphilis. Two of the live birth infants were not treated at delivery. All 6 cases represent missed opportunities for diagnosis and prevention, health department case investigation, and provider reporting. The identification of these cases for Arizona in 2006 demonstrates the limitations of a passive surveillance system for these sentinel disease events. In addition, unreported congenital syphilis cases may represent gaps in provider knowledge about required reporting and/or proper diagnosis and treatment. This study highlights the need for more timely and complete health department follow-up of positive syphilis tests among women in Arizona.
Congenital syphilis rates disproportionately affect minority and urban populations in Arizona.13,14 All 6 of the cases identified in this cross-match were born to women in racial/ethnic minority groups, with 67% of the cases and both stillbirths occurring among Hispanic mothers. These results mirror the racial disparities seen among reported congenital syphilis cases in Arizona and underscore the challenges in improving access, uptake, and quality of early prenatal care in these populations.13,14
The use of birth registries to compare the demographics of mothers of uninfected infants to those of congenital syphilis infants have been described previously.15,16 The utility of this cross-match method was demonstrated in this analysis as it identified currently reported cases as well as those that were unreported and/or undiagnosed. The reasons for diagnosis of these cases were similar to those identified in previous years and highlight missed opportunities for prevention.13,16 Lack of prenatal care and late prenatal care, seen for 3 of these 6 cases, are common contributors to congenital syphilis due to the lack of timely diagnosis and treatment opportunities.16–19 Health department intervention would not have prevented these cases. However, the maternal case that was treated less than 30 days before delivery would have benefited from health department intervention, which would have included testing and treatment recommendations for the infant at delivery. The case diagnosed due to a lack of adequate decline in titer after treatment would have benefited from health department intervention, which may have included recommendations for repeat testing after treatment to track decline in titer and initiation of retreatment if RPR titer drop was not timely. The remaining case reflected conflicting test results that reverted from positive to negative and then again to positive. Timely health department follow-up in this case would have included recommendations for treatment during pregnancy.
Limitations of passive surveillance for the identification of congenital syphilis were demonstrated from this cross-match of health department reporting registries. The addition of these six infants represents a 27% increase in the number of cases for 2006 and an annual rate per 100,000 live births increase from 17.1 to 23.5. In comparison, the Healthy People 2010 rate goal for congenital syphilis is 1.0 case per 100,000 live births.2,7 Reasons for provider nonreporting to the health department of these identified infants reflected lack of diagnosis of the cases and/or lack of knowledge of reporting requirements, both of which would have been prevented by timely identification and investigation of the maternal positive test values by the state and county health departments. Underreporting of congenital syphilis cases has been demonstrated in other regions due to lack of provider reporting.9,17,20,21 Identification of unreported cases would allow for adequate maternal/infant treatment, as well as more complete local and national surveillance, making available appropriate resource allocation based on actual morbidity.
Gaps in health department investigation of women with positive syphilis lab tests were evident in this analysis and reflect a breakdown in the timely communication and investigation of positive lab results by the state and county health departments, limited health department staff skilled in lab interpretation, and/or underutilized prioritization systems for case investigations.22 The results of this study will be used to reemphasize the need for timely investigation of women with positive syphilis lab results in Arizona and to ensure appropriate reporting and treatment of mothers and infants with syphilis via public health department and healthcare provider educational activities that emphasize the need for rapid assessment and management of women who test positive with syphilis. These results will also be used to support health policy related to prenatal syphilis testing and syphilis reporting that are deemed necessary to help reduce congenital syphilis in Arizona. As well, this evaluation identified three cases in which positive RPR results were not recorded in the STD database. A planned transition to electronic laboratory reporting will most likely improve time-to-reporting and the percentage of positive labs reported. Finally, the ADHS STDP will use this cross-match method of congenital syphilis case detection on an annual basis with particular focus on bringing to care untreated cases. Given the importance of identifying unreported and/or untreated infants with congenital syphilis, the methods presented here should be considered for use in other jurisdictions facing high or emergent congenital syphilis morbidity.
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. These are “The Congenital Syphilis Case Investigation and Reporting Form Instructions.” Accessed November 4, 2009.
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