Medical Outcomes Knowledge Item 62: Results from HRSA/HAB's SPNS Innovative Models of Care

Knowledge Item: CA-Medical Outcomes-62
Viral Load Outcomes Adjusted for Baseline CD4 Category

This Knowledge Item examines the relationship of three types of viral load outcomes studied in various Knowledge Items in this Knowledge Base adjusted for baseline CD4 Classification. The three types of outcomes are defined in the following way. Note that one of the types (the first, the clinical outcome) uses four different definitions because of issues in the sensitivity of viral load tests and the detectability levels at different times during the course of these projects (and with different assay methods including PCR and bDNA).

Variable	Definition
Clinical Outcome	A positive outcome is coded if the viral load decreased more than the clinical criterion at one time after the baseline assessment or is undetectable at follow-up; this definition is often used in medical clinics. A negative outcome is coded if the greatest decrease in viral load ever observed is less than the clinical criterion. Criterion 1: log change >= .3 and undetectable = 2.71 logs Criterion 2: log change >= .3 and undetectable = 3.01 logs Criterion 3: log change >= .5 and undetectable = 2.71 logs Criterion 4: log change >= .5 and undetectable = 3.01 logs More work on the different definitions for the clinically significant criterion is given in Knowledge Item: CA-Technical Issues-10.
Viral Load Maximum Outcome	The smallest viral load after the baseline is coded as a positive outcome if it is at or below the baseline level indicating that positive change occurred at least one time. A negative outcome is coded if the lowest viral load level after the baseline is above the baseline level.
Viral Load Change Status	The overall set of viral load assessments of the patient is considered. If the last assessment is at or below the baseline, a positive outcome is coded because the viral load is decreased or maintained at the final assessment. If the last assessment is above the baseline, a negative outcome is coded.

More Information: (Maximum) Outcome vs. Change Status

As can be seen in the results from this Knowledge Item, the three kinds of outcomes are significantly related to one another in a systematic way depending upon the definition of outcome.

62.9 percent of the patients has a clinically significant outcome under Criterion 1
65.3 percent of the patients had a clinically significant outcome under Criterion 2
59.1 percent of the patients had a clinically significant outcome under Criterion 3
62.0 percent of the patients had a clinically significant outcome under Criterion 4
61.0 percent of the patients had a viral load at the last time it was assessed that was below the baseline level
75.4 percent of the patients had at least one viral load result that was below the baseline level

More work on the different definitions for the clinically significant criterion is given in Knowledge Item: CA-Technical Issues-10.

More Information: (Maximum) Outcome vs. Change Status

More Information: CHAID and CHAID Diagram

Knowledge Item Citation: Huba, G. J., Melchior, L. A., Panter, A. T., and the HRSA/HAB SPNS Cooperative Agreement Steering Committee (1998-2001). Knowledge Item: CA-Medical Outcomes-62 from HRSA/HAB's SPNS Cooperative Agreements on Innovative Models of Care, The Measurement Group Knowledge Base on HIV/AIDS Care, Online at www.TheMeasurementGroup.com.

Last Updated: March 25, 2005; data through June 15, 1999; analyses conducted March 2001.

Knowledge Base Citation: The Knowledge Base and this Knowledge Item were designed and authored by G. J. Huba, Ph.D.; in collaboration with Lisa A. Melchior, Ph.D.; A. T. Panter, Ph.D.; and the staff of The Measurement Group. Cite this work as "Huba, G. J., Melchior, L. A., and Panter, A. T. (1998 - 2001). The Measurement Group Knowledge Base on HIV/AIDS Care. On the World Wide Web: http://www.TheMeasurementGroup.com."

Questions or Comments: Contact The Measurement Group.

Use of Knowledge Base Information: Acceptable Uses and Limitations.

Collaborators from Participating Projects: Cooperative Agreement Steering Committee 1999.

Participating Projects: This Knowledge Base is based on the service delivery experiences of 27 Cooperative Agreement Projects on Innovative Models of HIV/AIDS Care. These projects and the Evaluation and Dissemination Center which produced this Knowledge Base were funded by the Health Resources and Services Administration (HRSA), HIV/AIDS Bureau (HAB) as Special Projects of National Significance (SPNS) between 1994 and 1999. Click the Model Programs button above for descriptions of the projects that contributed to this specific Knowledge Item, a list of key staff, and project grant numbers.

Why This Evaluation was Conducted: Editorial.

More Information: Design of this Knowledge Base.

Recommended Citation Format for Web Materials: American Psychological Association Publication Manual Section, Revised 2001.

Work on the Knowledge Base and the cross-cutting evaluation was supported in part by Grant Number 5 U90 HA 00030-05 from the Health Resources and Services Administration (HRSA), HIV/AIDS Bureau's (HAB) Special Projects of National Significance (SPNS). The contents of this Knowledge Base are solely the responsibility of The Measurement Group and do not necessarily represent the official views of HRSA or HRSA/HAB's Special Projects of National Significance nor may they represent the positions of the individual grantees whose projects are included in the cross-cutting evaluation.