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. Per the recommendations: 1) the inclusion cutoff date criteria is MACS data collected as of October 1 of the most current year minus four years 2) the data comprise baseline and 6 month follow-up interview data, including medical history, behavior, SF36, physical examination data, frailty measurements, neuropsychology tests, and concurrent laboratory test results (Neopterin and B2-microgloubulin for selected participants from 1984 to 1992), and summary files of HIV status and medical events, 3) the identity of participants is further secured by replacing MACS IDS with randomized numbers and converting dates to year values, and 4) sensitive information is reclassified into broader category groupings (e.g., number of sexual partners were converted into categories: none, one, and one or more).

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. The release of data lags 4 years behind data collection.

Ordering Information: Go to the NTIS website, enter "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 6,972 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, study 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 6 month 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, 3, and 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

1. 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 questionnaires and laboratory results were generated.
   
   

2. New Recruit Cohort (Visit 75):

   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. Versions 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 has continued to be tested and interviewed along with the original cohort.
   
   

3. 2001-3 New Recruit Cohort (Visit 76/36.5):

   A third enrollment of 1,350 men [added to the Public Data Set in October 2009] took place between October 2001 and August 2003. This third cohort augments research efforts in the long term benefits and adverse effects of therapy.

   Recruitment was opened to focus on minorities and a special target group of censored seronegatives from the 1984 cohort. After administering a series of baseline questionnaires these participats have been followed every 6 months with the other cohorts.
   
   

4. Neuropsychological Cohort:
   

   From 1987 to June 1991, the MACS centers began administering neuropsychological interviews and tests to a subgroup of the original cohort across 10 neuropsychological specific testing waves.

   Beginning in April 1991 (Visit 15: April-September 1991) the conduct of neuropsychological tests were synchronized with the timing of the participant's semiannual MACS visit.

   Concurrently with the expansion in 2001, the MACS began administering a battery of neuropsychological tests at baseline and every 2 years for all participants from all cohorts.
   
   Waves 1-10 (April 1984- March 1991):

   • PHASE 1:
     
     • Form 07: Baseline questions administered at participants first neuropsychological testing Wave/Visit to assess general level of physical and intellectual functioning.
     • Form 08: Neuropsychological screening battery - psychological interview questions and tests (RAVLT, Rey Complex Figure, Pegboard, Stroop, and screening questions about recent loss of consciousness and substance abuse). Self report questions include headaches, visual problems, seizures, strength/mobility changes during past 3 months. A current status of mood and emotional problems.
     • Participants are moved to Phase 2 when their scores fall 3 standard deviations (SD) below mean on two different tests to a score of 3 SD below median of one test.
     • Participants can request to be tested by a neurologist.

   • PHASE 2:
     
     • Form 09: Further psychological testing. Participants were administered this test again when scores fall 1.5 SD below the mean of two different tests or 2.5 SD below the mean of one test.
     • Form 10: Neurological exam performed by a neurologist. Criteria to undergo Phase 2 testing again is determined by neurologists recommendation.
       

   Visit 15 - Current Visit (April 1991 - Current):

   • PHASE 1:
     
     • Form 07: Baseline questions administered at participants first neuropsychological testing Wave/Visit to assess general level of physical and intellectual functioning.
     • Form 18: Neuropsychological screening (Trails & Symbol Digit). Performed on all participants at every semi-annual visit.
       
     • California computerized Assessment Package (CalCAP; 1999; http://www.calcaprt.com) presents a series of brief reaction time tasks designed to assess speeded information processing and psychomotor functioning. Core measures are mean and median reaction time, hits and false positives, and signal detection parameters. The MACS uses the 4-subtest language-independent Abbvreviated battery (Simple RT, Basic C hoice RT, Sequential RT1, Sequential RT2) weighted toward measures of speeded processing and working memory.
     • Form 08: Continuation of Neuropsychological tests conducted in Waves 1-10 and an abbreviated set of questions to assess recent substance use and head injury.
       • Starting at Visit 36 (October 1, 2001) all participants were administered Form 08 for 2 consecutive MACS visits as the baseline.
       • As of Vist 44 (October 1, 2005) all MACS particpants are administered the Form 08 every two years.
     • Participants are moved to Phase 2 when their Form 18 scores fall 2 standard deviations (SD) below mean on two different tests or a score of 3 SD below median of one test.
     • Participants can request to be tested by a neurologist.

   • PHASE 2:
     
     • Form 10: Neurological exam performed by a neurologist. Criteria to undergo Phase 2 testing again is determined by neurologists recommendation.
       

5. Health Service Utilization and Economics:

   In 1990, health service utilization and economics questions 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).