Release Recommendations: MACS public data set has been released from CAMACS
(Center for Analysis and Management of Multicenter AIDS Cohort Study) since 1994 when
the MACS Executive Committee made the recommendations on the content of the public
data. Summary of the recommendations of the data set are as follows: 1) the cutoff date
for each release should be the October 1st of four years preceding the current MACS visit;
2) the data components will be visit information of physical examination, laboratory
results, Section 2 and 3, and Section 4, as well as data related to outcome, HIV status,
neopterin, B2-micro globulin and neuro-psychological; 3) information that might be used
to identify individuals should be modified; MACS IDs should be replaced by randomized IDs, all dates should be stripped of day value, and date of birth should retain only the year value; 4) quantitatively sensitive information should be presented as group data; for example, number of sexual partners should be categorized as none, one, and one or more
partners.
Release Schedule: The first release of the data was issued in March 1994. Beginning October 1995, the data has been released on a yearly schedule with new releases superceding previous versions.
Ordering Information: Go to the NTIS website, enter "PB2008-500028" or "Multicenter AIDS Cohort Study" in the search box and click on "Run Search" to find the most recent release (updates are sent annually in October), pricing and purchasing information.
Data Manipulation: The original MACS identification number contains information about each individual number; namely, his center at recruitment and original or new recruit status. We assigned a randomized identification number to each of the 5,622 participants. Once the data sets have been created, the original MACS IDs were deleted and the randomized IDs were sorted in their ascending order. In compliance with HIPAA regulations, the day and month of each participant's date of birth, visit, event report, clinical diagnosis, hospitalization, and death have been deleted, leaving only the year of each event. However, October and April are the start of each visit window. All quantitative information regarding sexual practice and use of illicit drugs were categorized so that it still remains useful for analysis and at the same time avoids the disclosure of detailed private information.
There are four sets of forms used repeatedly in regular semiannual visits. CAMACS organizes MACS data according to form type and visit number, resulting in a large number of files. Public data is based on data component rather than visit specific information, i.e., there is only one file for physical examination, laboratory results, sections
2 and 3, and section 4. Each of these data sets has a variable of "VISIT" to indicate with which visit the data is associated.
Before the data is released to the public, we sampled 10 percent of the variables from each public data set and compared them with the same set of variables in the raw files in each visit. All data files and their associated codebooks and SAS input statement files were also copied to the distribution media. The "README" file includes information describing the data files and cutoff date of the event files. Forms for the regular visits are included to be used to follow the codebook of each of the data set.
Data Medium: New variables, reflecting additions of research initiatives, will be incorporated in each new release of the public data set. The current release of public data was submitted on a CD-ROM disc in ASCII text of PC/Windows structure.
B. Data Components Included
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Original Cohort:
The original 4,954 gay and bisexual men volunteered since the
beginning of the MACS study in 1984. They were followed up
semi-annually. In each visit the data sets of physical examination,
sections 2, 3, and 4 of questionnaires and laboratory results were
generated.
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New Recruit Cohort:
From April 1987 through September 1991, recruitment was opened to
focus on minority and special target groups such as partners of the
original cohort. A total of 668 new participants were recruited.
Version of new recruit baseline questionnaires of physical
examination, sections 2, 3 and 4 were initially applied to this
cohort. In their follow-up visits this cohort was tested and
interviewed along with the original cohort.
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Neurophychological Cohort:
In 1987 MACS centers began administering neuropsychological tests
to a subgroup of the original cohort. The following forms were used
to collect their testing results. The NP wave specific interviews and
testing was ended by Wave 10. Beginning Visit 15 (April-September
1991) of the main cohort, NP related forms were administered at the
time of the participant's semi-annual visit.
Form 7: Baseline questions - asked at subject's first NP Wave visit
PHASE 1
Form 8:
- Neuropsychological screening battery - psychological tests.
- Neurological self-report questions - asks about headaches,
vision problems, seizures, and strength/mobility problems, during past
three months
PHASE 2
Form 9: Neuropsychological tests - further psychological testing
Form 10: Neurological exam - performed by a neurologist
DIAGNOSTIC TESTS: Participants were asked to undergo these tests
at random or based on the results of their PHASE 2 tests.
Electrodiagnostic tests
- Magnetic resonance imaging
- Lumbar puncture to collect cerebrospinal fluid
- Electro-encephalograph (ceased this test in 7/88)
-
Health Service Utilization and Economics:
In 1990, questions health service utilization and economics
related to HIV-1 disease were developed and piloted during visit 13
(April-September 1990). These questions were finalized and
incorporated in the regular visit questionnaire starting with MACS
visit 14 (October 1990 - March 1991).
C. Associated Questionnaire Forms and Documentation
Forms: Physical Examination, Sections 2, 3, and 4 of Visits 1 through 29 (April 1984 -
September 1998); Anti-viral Drug and Non Anti-viral Drug of visit 13 through 27;
Neuro-Psychological Testing; Clinical Outcome Reporting; and Health Economic and
Resource were submitted along with the distributed media.
Other documentation: Archives of MACS publications and directory of MACS
investigators can be browsed in the MACS home page.
D. Description of Files in the Released Data
