Concept: Syphilis - Method of Identification

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Concept Description

Last Updated: 2013-07-17

Introduction
    This concept provides a working definition of syphilis and describes the methods used at MCHP to investigate syphilis in the administrative data held in the Manitoba Population Research Data Repository. The concept lists the ICD-9-CM and ICD-10-CA diagnostic codes to identify syphilis in the hospital abstracts data and the medical services data, and lists the codes that are used in laboratory tests to investigate its presence in the population. SAS code (internal access only) is also available for working with the laboratory data.
Definition of Syphilis
    Syphilis is primarily a sexually transmitted infection (STI) caused by the spirochete bacterium Treponema pallidum. There are five stages to classify syphilis: primary, secondary, early latent, late latent, and tertiary. These stages reflect the progression of the infection and the communicability of the disease (Public Health Agency of Canada Website - Notifiable Diseases On-Line - Syphilis). Transmission is more probable during primary, secondary, and early latent stages. During these periods, the estimated risk of communicability is 60% per partner (Manitoba Health - Communicable Disease Control Unit - Communicable Disease Management Protocol - Syphilis). Symptoms can occur within a few weeks or a couple of months after infection. The first symptom may be a painless, open sore or ulcer where the bacteria first entered the body. Later symptoms include patchy hair loss, rash on soles of the feet or palms of the hands, fever, swollen glands, and muscle and joint pain. Symptoms usually disappear without treatment. If left untreated, syphilis can affect the brain, blood vessels, heart, and bones, and can eventually lead to death.

    Transmission of syphilis may also occur transplacentally from an untreated mother to the fetus or through the birth canal when the newborn infant contacts a genital lesion. Congenital transmission occurs predominantly when the mother is in the primary or secondary stage of infection. Although much less common, syphilis may also be transmitted though sharing of contaminated needles among injection drug users (Manitoba Health - Communicable Disease Control Unit - Communicable Disease Management Protocol - Syphilis).

    Because of the significant public health implications, syphilis is a notifiable disease in Canada since 1924 (Lix et al., 2012). All positive laboratory-confirmed cases of syphilis are reportable by laboratory operators and health care professionals to the Communicable Disease Control Unit of Manitoba Health.
MCHP Syphilis Algorithms
    The following two methods have been used at MCHP to determine testing and to identify individuals with syphilis.
1. Brownell et al. (2012)
2. Lix et al. (2012)
Table 1 - Syphilis: Serology Section
    STARTDT 1 STOPDT 2 AUXCD5 DESCR40
    12/2/1993 1/1/2099 ARPR SYPHILIS SCREEN
    12/2/1993 1/1/2099 CONF SYPHILIS CONFIRMATORY
    1/1/1990 1/1/2099 DFA SYPHILIS DIRECT EXAM
    1/25/2002 2/29/2007 DFAR SYPHILIS DIRECT FLUORESCENT ANTIBODY
    1/1/1990 12/3/1993 FTABS SYPHILIS REFERENCE
    1/1/1990 12/3/1993 IGM SYPHILIS IGM
    1/1/1990 12/3/1993 MHATP SYPHILIS CONFIRMATORY
    12/2/1993 1/1/2099 REF SYPHILIS REFERENCE
    1/1/1990 12/3/1993 RPR SYPHILIS SCREEN
    12/2/1993 5/1/2006 SIGM SYPHILIS IGM
    1/1/1990 1/1/2099 SYRPR SYPHILIS SCREEN
    1/1/1990 12/3/1993 VDRL SYPHILIS QUANTITATIVE
    12/02/93 01/01/99 BVDRL SYPHILIS QUANTITATIVE

    1 - The date that the code was created in the file.
    2 - The date that the code became inactive.
Comparison of Lab Data to Hospital Discharge Abstracts and Medical Services Data
SAS Code
    SAS code for identifying syphilis tests in the Cadham Provincial Laboratory data is available in the SAS code and formats section below (internal access only).
Limitations /Cautious
  • Cadham Provincial Laboratory performs virtually all clinical serologic testing and screening for syphilis in Manitoba, but laboratory data may not capture all cases in a jurisdiction.

  • The technology for testing various STI or STBBIs has changed over the last several years; therefore examining trends in these infections may not reflect actual trends in the infections themselves but changes in detection. For this reason, syphilis was examined not over time but for a single year in Brownell et al. (2012) .

  • A value of P [Positive] to identify a positive test result in the POSNEG field [Positive-Negative] for specific AUXCD5 codes in the CPL data was used to determine a positive test result.

  • The AUXCD5 codes used to identify syphilis in the Serology Section should be verified at the beginning of each new study to ensure they are up-to-date.

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References 

  • Brownell M, Chartier M, Santos R, Ekuma O, Au W, Sarkar J, MacWilliam L, Burland E, Koseva I, Guenette W. How are Manitoba's Children Doing? Winnipeg, MB: Manitoba Centre for Health Policy, 2012. [Summary] [Full Report] [Data extras] [Errata] (View)
  • Lix L, Smith M, Azimaee M, Dahl M, Nicol P, Burchill C, Burland E, Goh C, Schultz J, Bailly A. A Systematic Investigation of Manitoba's Provincial Laboratory Data. Winnipeg, MB: Manitoba Centre for Health Policy, 2012. [Summary] [Full Report] (View)