Models:
(1) final Cox model
(2) simplified Cox model
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Cox Model
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Simplified Model
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IgA
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IgA
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CD4 count
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lymphocyte count
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immune complexes
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immune complexes
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>= 2 symptoms
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>= 2 symptoms
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early high-risk contacts
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Units for parameters:
(1) IgA in mg/dL
(2) CD4 per µL
(3) lymphocyte per µL
(4) immune complexes as percent C1q binding (using the iodine-125 labelled C1q binding)
Parameters graded as 0 if negative or 1 if positive:
(1) early high-risk contacts: >= 20 male sexual partners in high-risk areas (New York City, San Francisco, Los Angeles, other) in the 5 years prior to enrollment
(2) >= 2 symptoms (fever, weight loss, fatigue, diarrhea, arthralgia, thrush, herpes zoster, cough not due to smoking, dyspnea) in the past 12 months
final Cox model =
= (0.0055 * (IgA)) - (0.0026 * (CD4 count)) + (0.036 * (immune complexes)) + (0.8731 for 2+ symptoms) + (0.623 for early high-risk contact)
simplified Cox model =
= (0.0060 * (IgA)) - (0.0008 * (lymphocyte count)) + (0.0426 * (immune complexes)) + (0.8806 for 2+ symptoms)
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Risk Group
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Final Cox Model
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Simplified Model
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low
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<= -0.65
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<= -0.052
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intermediate
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-0.66 to 0.65
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-0.053 to 0.729
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high
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>= 0.66
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>= 0.730
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where:
• Progression by the simplified model was 7% for the low risk group, 19% for the intermediate group and 56% for the high risk group.
Limitations:
• The models were developed prior to availability of HAART, which has significantly improved survival. The score can provide an estimate if HAART is refused or unavailable.
• The assay for C1q and immune complexes may be difficult to find (Zubler RH, et al. Detection of immune complexes in unheated sera by a modified 125I-C1q binding test. Effect of heating on the binding of C1q by immune complexes and application of the test to systemic lupus erythematosus. J Immunol. 1976; 116: 232-235.
