Spectrum 2021: revise ART dropout code to increase by 1 CD4 category

[jeffeaton]

Spectrum 2021 was updated to increase individuals dropping out from ART by 1 CD4 category. This change should be implemented in the EPP-ASM code.

These changes should also be propagated to first90 and CSAVR code bases.

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Description of required code changes from Tim Brown:

Wanted to let you know the changes I made to the ASM in order to incorporate the movement to the next higher CD4 level. They’re not extensive, but thought I’d send them along so Jeff could review them and see if he wants to incorporate them into eppasm.cpp.

I added two static ints (i.e., just index variables named to make the code more legible):

           private static final int CD4_GT_500 = 0;
           private static final int CD4_LT_50 = 6;

I added a variable everARTeligMinus1:

           int everARTeligMinus1 = everARTelig_idx > 0 ? everARTelig_idx - 1 : 0;

This is just used to allow the artDropout code to include the next higher CD4 category in its loop where people are moved to the next higher level.

Than I modified the art_dropout code by adding what’s highlighted with yellow highlight in the attached PDF file:

This just does the move-up to the next CD4 for those on ART >1 yr for each CD4 category, correctly for the add-ins that were done by the original art_dropout loop which included everyone. I decided this was easier than trying to modify the inner loop, while still maintaining the computational efficiencies by not going more than one CD4 level above where ART was ever assigned in the loops.

PDF with code changes highlighted:

Changes to ASM code for ART dropout bump-up.pdf