Table 2. Clinical and demographic characteristics of the Johns Hopkins University study cohort, total and according to IDU risk category.a .
| Characteristic | Total cohort (n = 1977) | No IDU history (n = 1246) | IDU history (n = 731) | P valueb |
| Age in years | 39 (34–45) | 38 (32–44) | 41 (37–46) | <0.001 |
| Black race | 1458 (74) | 859 (69) | 599 (82) | <0.001 |
| Female sex | 683 (35) | 438 (35) | 245 (34) | 0.46 |
| Follow-up time in weeks | 171 (93–255) | 176 (97–257) | 164 (88–162) | 0.25 |
| Baseline CD4+ T cell countc, cells/mm3 | 273 (105–466) | 274 (98–467) | 272 (117–461) | 0.79 |
| Baseline HIV-1 RNAc, log10 copies/mL | 4.4 (3.1–5.1) | 4.4 (3.1–5.1) | 4.4 (3.2–5.1) | 0.56 |
| Baseline CD4+ T cell countc <200 cells/mm3 | 764 (39) | 486 (39) | 278 (38) | 0.70 |
| Baseline HIV-1 RNAc <400 copies/mL | 352 (18) | 230 (19) | 122 (17) | 0.60 |
| HAART ever during study periodd | 1429 (72) | 948 (76) | 481 (66) | <0.001 |
| Time on HAART in weekse | 123 (52–220) | 129 (57–226) | 112 (41–209) | <0.001 |
| % follow-up time on HAART among ever exposed to HAART (n = 1429) | 96 (55–100) | 97 (63–100) | 87 (40–100) | <0.001 |
a
Data are median (interquartile range) or n (%).
b
P-values are for comparisons between IDU and no IDU history groups using Wilcoxon rank-sum or Fisher's exact tests.
c
CD4+ T cell counts and plasma HIV-1 RNA levels not available for all persons; data shown are for those persons with data available. Baseline laboratory values defined as the first value obtained on or after the initial office visit, between January 1, 1999 and December 31, 2004.
d
Defined as at least 7 days of continuous HAART.
e
Among persons ever exposed to HAART.
IDU = injection drug use; HAART = highly active antiretroviral therapy.