Using HIV surveillance data to monitor missed opportunities for linkage and engagement in HIV medical care.

Monitoring delayed entry to HIV medical care is needed because it signifies that opportunities to prevent HIV transmission and mitigate disease progression have been missed. A central question for population-level monitoring is whether to consider a person linked to care after receipt of one CD4 or VL test. Using HIV surveillance data, we explored two definitions for estimating the number of HIV-diagnosed persons not linked to HIV medical care. We used receipt of at least one CD4 or VL test (definition 1) and two or more CD4 or VL tests (definition 2) to define linkage to care within 12 months and within 42 months of HIV diagnosis. In five jurisdictions, persons diagnosed from 12/2006-12/2008 who had not died or moved away and who had zero, or less than two reported CD4 or VL tests by 7/31/2010 were considered not linked to care under definitions 1 and 2, respectively. Among 13,600 persons followed up for 19-42 months; 1,732 (13%) had no reported CD4 or VL tests; 2,332 persons (17%) had only one CD4 or VL test and 9,536 persons (70%) had two or more CD4 or VL tests. To summarize, after more than 19 months, 30% of persons diagnosed with HIV had less than two CD4 or VL tests; more than half of them were considered to have entered care if entering care is defined as having one CD4 or VL test. Defining linkage to care as a single CD4 or VL may overestimate entry into care, particularly for certain subgroups.