Similarities
· Relational databases of infectious diseases;
· Global in scope;
· Built for queries to generate differential diagnosis lists;
· Can query by place, findings (signs & symptoms), and epidemiological factors;
Differences
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GIDEON
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IDdx
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GIDEON sorts the differential diagnosis list by "a Bayesian formula which compares the product of disease-incidence and symptoms incidence, for all compatible infectious diseases."1
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IDdx sorts the list alphabetically.
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GIDEON profiles 340 infectious diseases: a.) including rare diseases such as astrakhan fever, acanthocephalan worms, bertielliasis, coenurosis, cicrocoeliasis, and dioctophyme renalis infection, and b.) splitting "Viral encephalitides, tickborne," Viral encephalitides, mosquito-borne," "Arthropod-Borne Viral Arthritis and Rash," and "Boutonneuse fever" into 24 separate diseases.
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IDdx includes 250 infectious diseases similar to those covered in the Control of Communicable Diseases Manual (CCDM).4 The categories "Viral encephalitides, tickborne," Viral encephalitides, mosquito-borne," "Arthropod-Borne Viral Arthritis and Rash," and "Boutonneuse fever" are used in CCDM.
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The first version of GIDEON was developed by an infectious disease specialist in the early 1990s using Paradox.
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The first version of IDdx (infectious diseases in Haz-Map) was developed by a board certified family practice and occupational medicine physician in the early 1990s using Microsoft Access;
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GIDEON searches for diseases related to any of about 240 countries.
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IDdx searches by regions using the CDC’s list of 19 regions of the world.
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GIDEON includes modules on Diagnosis, Epidemiology, Therapy, and Microbiology.
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IDdx focuses on decision support for Diagnosis.
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GIDEON costs $995 per year or $99.95 per month as a web application.
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IDdx costs $11.99 as an iPhone app.
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Advantages of IDdx
The new edition of IDdx in 2011 will include queries by occupation and incubation period. Queries by jobs are not available in GIDEON.
There are advantages and disadvantages of using algorithms, such as the Bayesian formula in the GIDEON decision-support system. One disadvantage is confusing the user with statistical percentages, e.g., stating a 19.3 % likelihood when full knowledge about the disease and its occurrence in the world is incomplete. IDdx relies simply on database queries, which are transparent to the user. Queries generate lists (all diseases that have cough as a symptom) or intersections of lists (all diseases that have cough AND rash as symptoms).
The Bayesian formula used in GIDEON to rank diseases is a black box, and the doctor does not know where the data comes from, how accurate it is, and all the assumptions that were made. A list sorted on most likely doesn't make sense if it is a bioterrorism event or a new emerging infectious disease outbreak.
In one study of GIDEON, the program generated a median of 29 diagnoses per case and a median of 23 diagnoses with a probability of lower than 1%, that is, 88% of the diseases were not ranked.2 In a differential list of all severe infectious diseases acquired in Indonesia with an incubation period of 1-2 weeks and symptoms of fever, arthralgia, and neutropenia, GIDEON generated a list of 40 infectious diseases, and all but five were listed as <1%, that is, the Bayesian formula did not rank 88% of the diseases in the list.1 Putting the same case findings in IDdx resulted in a list of 29 diseases (symptoms only), 11 diseases (symptoms and acuity), and four diseases when this fact in the case was added, “The patient experienced multiple mosquito bites.”1 The differential diagnosis provided by IDdx was:
1. Arthropod-borne viral arthritis and rash;
2. Dengue fever:
3. Sepsis;
4. West Nile virus infection;
All of the links between diseases and findings in IDdx have been checked against GIDEON, as well as against electronic versions of CCDM4, PPID7, and Cohen5.
Several findings in IDdx are not available for queries in GIDEON: wheezing, dyspnea, sputum production, nasal ulcers, entry wound with lymph nodes, nodular lymphangitis, rash on palms, pyuria, fecal leucocytes, hemoglobinuria, hypergammaglobulinemia, opisthotonus, oculoglandular syndrome, transverse myelitis, glomerulonephritis, cirrhosis, and weight loss.
There are many disease-symptom links in IDdx that are not found in GIDEON. For example, the following are documented causes of pleural effusion that are not listed in GIDEON: Toxoplasmosis, Salmonellosis, Hepatitis B infection, and Candidiasis.
There are also many disease-symptom links in GIDEON that could not be confirmed. The following diseases are listed in GIDEON as rarely linked to pleural effusion: Adenovirus infection, Babesiosis, Bartonellosis, Cysticercosis, Ebola, Filariasis (Bancroftian), Hantavirus pulmonary syndrome, Hendra virus disease, Kyasanur forest disease, Measles, Omsk hemorrhagic fever, Paracoccidioidomycosis, Pertussus, Rheumatic fever, Smallpox, Sporotrichosis, Tetanus, Toxic shock syndrome, Typhoid fever, Typhus (endemic, epidemic, and scrub), and Yersiniosis. These disease-symptom links (not yet documented or confirmed) were not added to IDdx.
Conclusions
The relational database is a new tool for indexing infection disease information for improved prevention, diagnosis, and treatment. Compared to the advanced applications that will be available in the future, IDdx and GIDEON are prototype applications that have been in development since the early 1990s. Neither application is perfect, mainly because our understanding of infectious diseases is still incomplete. At this stage, it is important to use both to build differential diagnosis lists and to check the results of one against the other.
References
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Berger SA. GIDEON: a comprehensive Web-based resource for geographic medicine. Int J Health Geogr. 2005 Apr 22;4(1):10.
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Bottieau E, Moreira J, Clerinx J, Colebunders R, Van Gompel A, Van den Ende J. Evaluation of the GIDEON expert computer program for the diagnosis of imported febrile illnesses. Med Decis Making. 2008 May-Jun;28(3):435-42.
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Brown JA. Using a relational database to index infectious disease information. Int J Environ Res Public Health. 2010 May;7(5):2177-90.
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CCDM Heymann DL (ed). Control of Communicable Diseases Manual, 19th Ed. Washington, DC: APHA, 2008. CCDM Online
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Cohen J, Opal SM, Powderly WG (eds). Infectious Diseases, 3rd Ed. Philadelphia: Elsevier, 2010. Cohen Online
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GIDEON
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PPID Mandell GL, Bennett JE, Dolin R (eds). Principles and Practice of Infectious Diseases, 7th Ed. Philadelphia: Elsevier, 2010. PPID Online
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