Concept: Gonorrhea - Method of Identification

Introduction

This concept provides a working definition of gonorrhea and describes the methods used at MCHP to investigate gonorrhea 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 gonorrhea 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 Gonorrhea

Gonorrhea is a sexually transmitted infection (STI) caused by the bacterium Neisseria gonorrhoeae. If left untreated, it may increase the risk of contacting Human Immunodeficiency Virus (HIV) (Dickerson et al., 1996), pelvic inflammatory disease, ectopic pregnancy, and infertility in females or urethritis, epididymitis, and gonococcal arthritis in males (Merck Research Laboratories, 1992). Gonorrhea may also cause pharyngeal and anorectal infections in females and homosexual males (Chin, 2000). Symptoms may be absent, or may appear within 1-4 weeks after infection. Symptoms include (but are not limited to) a feeling of burning or pain while urinating, increased urination, penile or vaginal discharge, or tender or swollen genitals.

NOTE: The original reference for this information is (U.S National Library of Medicine - PubMed Health: Gonorrhea, 2011 - the URL was: http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0004526/ - accessed October 15, 2012). On October 31, 2018, the resource PubMed Health was discontinued and is no longer available. For more information about gonorrhea, see: MedlinePlus® - Health Topics - Gonorrhea

Because of its significant public health implications, gonorrhea is a notifiable disease in Canada since 1924 (Lix et al., 2012). All clinical and laboratory-confirmed cases are reportable to the Communicable Disease Control Branch, Manitoba Health and Healthy Living. For more information on gonorrhea, see the Government of Canada - Public Health - Gonorrhea Case Definition and the Manitoba Health - Public Health Website - Gonorrhea .

MCHP Gonorrhea Algorithms

The following methods have been used at MCHP to identify testing and to identify individuals with gonorrhea.

1. Brownell et al. (2012)

In Brownell et al. (2012), the percent of youths aged 13 to 19 years with at least one positive detection for gonorrhea in the Cadham Provincial Laboratory (CPL) database in the fiscal year 2008/09 was examined. A positive detection was defined as:


• Neisseria gonorrhoeae identified in the Clinical Microbiology Section - Organism file (see Table 1 for the AUXCD5 code), OR
  
  
• Neisseria gonorrhoeae isolated beta lactamase negative, Neisseria gonorrhoeae beta lactamase positive, Neisseria gonorrhoeae detected, or presumptive Neisseria gonorrhoeae detected from the Clinical Microbiology Section - Results file (see Table 2 for the AUXCD5 codes).
  
  NOTE: Table 3 lists the gonorrhea tests available in the Serology Section of the CPL data. In Brownell et al. (2012) , this was investigated and reviewed but not included as part of the gonorrhea results.

The percent of youths with at least one positive detection for gonorrhea in Manitoba was higher for females (0.4%) than for males (0.2%) (p<0.01) with a provincial average of 0.3%. The lowest frequency was in the Rural South (0.08%) and the highest was in the North (1.2%). A Socioeconomic Status (SES) gradient for gonorrhea in rural areas was identified with the highest percentage found in the areas with the lowest income. Furthermore, the lowest income quintiles had much higher positive gonorrhea detection in both urban and rural areas. For more information read the section Gonorrhea in Brownell et al. (2012) .

Table 1 - Gonorrhea: Clinical Microbiology Section - Organism

STARTDT 1	STOPDT 2	AUXCD5	DESCR40
4/10/1992	1/1/2099	NG	NEISSERIA GONORRHOEAE

¹ - The date that the code was created in the file.
² - The date that the code became inactive.

Table 2 - Gonorrhea: Clinical Microbiology Section - Results

STARTDT 1	STOPDT 2	AUXCD5	DESCR70
4/10/1992	1/01/2099	FAT	F.A. TEST FOR N.GONORRHOEAE POS. UNABLE TO CONFIRM. CULTURE NON-VIABLE
8/20/2004	1/01/2099	GRNR	GONORRHEA RESULT NOT REPORTED
4/10/1992	1/01/2099	GRU	GONORRHOEA RESULT UNINTERPRETABLE. PLEASE REPEAT
4/10/1992	1/01/2099	NGBLN	N. GONORRHOEAE ISOLATED. BETA LACTAMASE NEGATIVE
4/10/1992	1/01/2099	NGBLP	N. GONORRHOEAE ISOLATED. BETA LACTAMASE POSITIVE
4/10/1992	1/01/2099	NGD	NEISSERIA GONORRHOEAE DETECTED
4/10/1992	1/01/2099	NGND	NEISSERIA GONORRHOEAE NEGATIVE
4/10/1992	1/01/2099	NGNI	N. GONORRHOEAE NOT ISOLATED
4/10/1992	4/10/1992	NGP	N. GONORRHOEAE POSITIVE
5/13/2002	1/01/2099	NGRIN	GONORRHOEAE RESULT INDETERMINATE
2/20/2002	1/01/2099	NGRU	NEISSERIA GONORRHOEAE RESULTS UNAVAILABLE
4/04/2002	1/01/2099	PNG	PRESUMPTIVE NEISSERIA GONORRHOEAE DETECTED
4/10/1992	4/10/1992	PP	PRESUMPTIVE POSITIVE FOR N.GONORRHOEAE. INTERPRETATION IS DEPENDANT ON
7/17/1997	1/01/2099	RNG	RE:ANTIGEN TESTING FOR N. GONORRHOEAE.

¹ - The date that the code was created in the file.
² - The date that the code became inactive.

Table 3 - Gonorrhea: Serology Section

STARTDT 1	STOPDT 2	AUXCD5	DESCR40
01/01/1990	11/07/1994	GON	N.GONORRHEA
11/07/1994	05/01/2006	GONO	ANTIBODY TO N.GONORRHEA


¹ - The date that the code was created in the file.
² - The date that the code became inactive.

2. Lix et al. (2012)

In Lix et al. (2012), the Cadham Provincial Laboratory (CPL) data from 1992/93 to 2008/09 was used to identify the total number of gonorrhea tests and the frequency of positive tests (laboratory-confirmed cases) by fiscal year in Manitoba. Less than 3% of all gonorrhea tests were positive in each of the study years. For more information on CPL, see the CADHAM Provincial Laboratory (CPL) - Overview of Services and Data concept.

Data from the CPL Clinical Microbiology Section - Organism file was used to identify the pathogenic bacterium Neisseria gonorrhoeae . Table 1 reports the AUXCD5 code for this organism. The Clinical Microbiology Section - Results file was used to identify the CPL number of gonorrhea tests and the frequency of positive laboratory-confirmed cases in Manitoba. Table 2 lists the AUXCD5 codes used to report the results of these tests.

Comparison of Lab Data to Hospital Discharge Abstracts and Medical Services Data

Gonorrhea diagnoses from the hospital abstracts data and the medical services data were compared to the CPL data. ICD-9-CM codes 098, V02, V02.7 and ICD-10-CA codes A54 were used to identify the diagnoses of gonorrhea. Only a small proportion of positive tests (laboratory-confirmed cases) for gonorrhea had a corresponding diagnosis in hospital or physician claims data, regardless of the size of the reference window applied to the data (diagnosis within 30, 90, and 180 days before or after the index date in the CPL data). For more information on how gonorrhea was investigated in the CPL data, read the section titled Case Study #3:Sexually Transmitted Infection Tests in CPL Data and Sexually Transmitted Infection Diagnoses in Hospital and Physician Billing Records in Lix et al. (2012) .

SAS Code

SAS code for identifying gonorrhea tests in the Cadham Provincial Laboratory is available in the SAS code and formats section below (internal access only).

Limitations / Cautions

• CPL performs virtually all tests for gonorrhea in Manitoba, but laboratory data may not capture all gonorrhea cases in a jurisdiction.
  
  
• In the Medical Services / Physician Claims data, the diagnosis recorded is limited to one, 3-digit ICD-9-CM code. In some cases, the 3-digit code is not specific enough to uniquely identify conditions and if used, may over report certain conditions. NOTE: In December 2018, a 5-digit diagnosis code variable was added to the Medical Services data. If recorded, the first 3-digits of both the 3-digit and 5-digit diagnosis code variables will match exactly. The 5-digit diagnosis code variable applies to records from 2015/16 forward.
  
  
• A value of P [Positive] to identify a positive test result in the POSNEG field [Positive-Negative] or the presence of specific AUXCD5 codes for gonorrhea detection in the CPL data was used to determine if an individual was positive for gonorrhea.
  
  
• The AUXCD5 codes used to identify gonorrhea in the CPL data should be verified at the beginning of each new study to ensure they are up-to-date.