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Diagnostic accuracy of three clinical case definitions for advanced HIV disease
J E Gallant1, J Somani, R E Chaisson
1Division of Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, Maryland.
Insights
Clinical case definitions for advanced HIV disease, including WHO and Caracas criteria, showed high specificity but moderate sensitivity in a US study. Further research in diverse regions is recommended for accurate HIV staging.
Area of Science:
- Infectious Diseases
- Immunology
- Public Health
Background:
- Accurate clinical case definitions are crucial for diagnosing advanced HIV disease.
- Existing definitions, such as those from the World Health Organization (WHO) and Caracas, require validation in diverse populations.
- The Centers for Disease Control (CDC) staging criteria and CD4 cell counts serve as benchmarks for assessing advanced HIV.
Purpose of the Study:
- To evaluate the diagnostic accuracy of three clinical case definitions for advanced HIV disease.
- To compare the sensitivity, specificity, and predictive values of the WHO, original Caracas, and revised Caracas definitions.
- To correlate definition accuracy with CD4 cell counts in HIV-positive adults.
Main Methods:
- Retrospective chart review of 224 HIV-positive adults at a tertiary care university hospital in Baltimore, Maryland.
- Assignment of scores based on initial evaluation according to each case definition.
- Calculation of sensitivity and specificity using CDC staging criteria (Stage IV as positive, Stage II-III as negative) and correlation with CD4 cell counts.
Main Results:
- The revised Caracas definition demonstrated the highest sensitivity (60%) compared to WHO (40%) and original Caracas (67%) when using CDC Stage IV as the standard.
- All definitions exhibited high specificity (99-100%) for identifying patients not having advanced HIV (CDC Stage II-III).
- Mean CD4 cell counts for patients meeting the case definitions were similar to those with CDC Stage IV disease, but sensitivity decreased when including all patients with CD4 counts <200 cells/µL.
Conclusions:
- The evaluated clinical case definitions for advanced HIV disease are specific but only moderately sensitive in this US-based study population.
- Prospective studies in diverse geographic settings are necessary to refine these definitions.
- Incorporating lymphocyte or CD4 cell counts into case definitions may improve accuracy for advanced HIV disease detection.
Objective:
To assess the accuracy of three clinical case definitions for advanced HIV disease: the World Health Organization (WHO) case definition, and the original and revised Caracas case definitions.
Design:
Retrospective chart review.
Setting:
A clinic for patients with all stages of HIV infection at the Johns Hopkins Hospital, Baltimore, [correction of Bethesda] Maryland, USA, a tertiary care university hospital.
Patients, Participants:
Two hundred and twenty-four HIV-positive adults who underwent initial evaluation between 1 January 1990 and 31 December 1990.
Main Outcome Measures:
A score for each definition was assigned based on initial evaluation. The sensitivity, specificity, and predictive values were calculated using the Centers for Disease Control (CDC) staging criteria, and results were correlated with total CD4 cell counts.
Results:
The sensitivities of the WHO, and the original and revised Caracas definitions were 40, 67, and 60%, respectively, using CDC disease stage IV as a positive standard. Specificities were between 99 and 100%, using CDC stage II-III disease as a negative standard. Mean CD4 cell counts for patients with positive scores were 184, 160, and 158 x 10(6)/l, respectively, compared to 191 x 10(6)/l for CDC stage IV patients. Sensitivity was lower when the positive standard was expanded to include all patients with CD4 cell counts less than 200 x 10(6)/l.
Conclusions:
In our study population, case definitions were specific, but only moderately sensitive for advanced HIV disease. Prospective studies should be conducted in diverse geographic regions, using lymphocyte or CD4 cell counts when possible.