Increase in CD4 Count Among New Enrollees in HIV Care
Increase in CD4 Count Among New Enrollees in HIV Care
We identified 13,543 newly presenting patients who enrolled in the HIVRN between 2003 and 2011: 7200 between 2003 and 2007 and 6343 between 2008 and 2011. The median number of new patients was 1370 per year over the interval 2003–2007 and 1582 per year over the interval 2008–2011 (P = 0.142). The median number of new patients per year for whites was 401.5 during 2003–2007 and 382 during 2008–2011 (P = 0.54), for blacks it was 641.5 during 2003–2007 and 791 during 2008–2011 (P = 0.086), and for Hispanics it was 285 during 2003–2007 and 309 during 2008–2011 (P = 0.806). Patient characteristics stratified by time period appear in Table 1 (Fig. 1).
(Enlarge Image)
Figure 1.
Mean and predicted mean CD4 count at enrollment among new presenters from 2003 to 2011 with the corresponding 95% CI. *Solid lines denote mean CD4 count at enrollment predicted by the MLR model (Table 3) for all new presenters. The dashed lines denote the actual mean CD4 count at enrollment for all new presenters. Enrollment CD4 was predicted for each subject using the adjusted MLR (Table 3), and the mean of the predicted enrollment CD4 was plotted for each enrollment year. As the inputs to the model (the demographic and behavioral risk composition of the underlying cohort) vary from year to year, the mean predicted CD4 may not be perfectly linear when plotted against calendar year.
Overall, the median CD4 at enrollment rose from 285 to 317 cells per cubic millimeter between 2003–2007 and 2008–2011 (P < 0.001) (results not shown). Median CD4 counts for 2003–2007 and 2008–2010 stratified by demographics are shown in Table 2 .
The percentage of newly presenting subjects with CD4 at enrollment ≥350 cells per cubic millimeter increased from 40.8% in 2003–2007% to 44.3% in 2008–2011 (χ = 19.7, P < 0.001). There was no increase in the mean percentage of subjects with CD4 ≥350 cells per cubic millimeter during 2003–2007 (-0.19% [95% confidence interval (CI) -0.90% to 0.52%]), but there was an increase of 1.45% per year (0.73%, 2.16%) from 2008 to 2011 (results not shown).
The unadjusted annual mean CD4 at enrollment did not significantly increase over the interval 2003–2007 (-1.8 cells per cubic millimeter per year, 95% CI -5.7 to 2.2) but increased by 12.3 cells per cubic millimeter per year (95% CI 8.5 to 16.1) over the interval 2008–2011, for an overall mean increase in CD4 per year of 14.1 cells per cubic millimeter per year (7.1, 21.0) (results not shown). After adjusting for demographic factors and clinic site, the annual mean CD4 at enrollment did not significantly increase interval 2003–2007 but did significantly increase by 11.2 cells per cubic millimeter per year (7.4, 14.9) over the interval 2008–2011 ( Table 3 ). The difference in the slope was 13.3 cells per cubic millimeter per year (6.4, 20.1) comparing 2003–2007 with 2008–2011. Females had a higher CD4 at enrollment than did males ( Table 3 ). Variations by age, race/ethnicity, and HIV risk are addressed in the following section.
Race/Ethnicity. In 2003, the adjusted mean CD4 at enrollment was 69.3 cells per cubic millimeter (28.5, 110.0) greater in whites than in blacks, 69.2 cells per cubic millimeter (25.6, 112.8) greater in whites than in Hispanics, and not significantly different between blacks and Hispanics. In 2011, the adjusted mean CD4 at enrollment was 49.3 cells per cubic millimeter (13.6, 83.0) greater in whites than in blacks, 59.0 cells per cubic millimeter (17.8, 100.2) greater in whites than in Hispanics, and not significantly different between blacks and Hispanics.
The difference in the slope between 2003 and 2007 and 2008 and 2011 was 19.3 cells per cubic millimeter per year (5.9, 32.8) for whites and 10.8 cells per cubic millimeter per year (0.9, 20.6) for blacks, but there was no significant increase in Hispanics (11.3 cells per cubic millimeter per year [-2.3, 24.9]) or OTH race [16.2 cells per cubic millimeter per year (-23.0, 55.4)] (Fig. 2 and Table 4).
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Figure 2.
Mean and predicted mean CD4 count at enrollment among new presenters from 2003 to 2011 stratified by race/ethnicity (panel A) and age category (panel B). *Solid lines denote the mean CD4 count at enrollment predicted by the MLR model (Table 4) for all new presenters, stratified as indicated. The dashed lines denote the actual mean CD4 count at enrollment for all new presenters, stratified as indicated. Other race is not shown. Enrollment CD4 was predicted for each subject using the adjusted MLR (Table 4), and the mean of the predicted enrollment CD4 was plotted for each enrollment year. As the inputs to the model (the demographic and behavioral risk composition of the underlying cohort) vary from year to year, the mean predicted CD4 may not be perfectly linear when plotted against calendar year.
HIV Risk. In 2003, the adjusted mean CD4 at enrollment was 79.3 cells per cubic millimeter (45.0, 113.6) greater in MSM than in heterosexual risk, 70.8 cells per cubic millimeter (10.7, 130.9) greater in IDU than in heterosexual risk, and not significantly different between MSM and IDU. In 2011, the adjusted mean CD4 at enrollment was 45.2 cells per cubic millimeter (12.7, 77.7) greater in MSM than in heterosexual risk and not significantly different between either MSM and IDU or IDU and heterosexual risk.
MSM and heterosexual risk groups had an increase in the slope of CD4 at enrollment per year over the interval 2008–2011 (Table 4). There was no increase in the slopes of CD4 at enrollment per year among IDU and other HIV risk categories over the interval 2008–2011 (Table 4).
Age. For those aged >30 years, age categories did not differ in adjusted mean CD4 at enrollment in 2003. In 2003, subjects aged ≤30 years had an adjusted CD4 at enrollment greater than subjects in age categories 31–40 years [69.1 cells per cubic millimeter (30.4, 107.8)], 41–50 years [82.5 cells per cubic millimeter (40.7, 124.2)], and >50 years [72.5 cells per cubic millimeter (-13.8, 158.9)—not significant]. In 2011, the adjusted mean enrollment CD4 was 63.4 cells per cubic millimeter (17.5, 109.3) greater in 31–40 years than in >50 years, but not significantly different between either 31–40 and 41–50 years or 41–50 and >50 years. However, the adjusted 2011 mean enrollment CD4 in subjects ≤30 years was greater than in subjects in age categories 31–40 years [52.1 cells per cubic millimeter (16.0, 88.3)], 41–50 years [79.9 cells per cubic millimeter (41.8, 117.9)], and >50 years [115.5 cells per cubic millimeter (72.2, 158.8)].
CD4 at enrollment increased per year over the interval 2008–2011 for age categories ≤30, 31–40, 41–50 years, but not for >50 years (Fig. 2 and Table 4). Compared with age category >50 years, the CD4 at enrollment slope over the interval 2008–2011 was greater in age categories ≤30 years (13.4 cells per cubic millimeter per year [0.9–25.9]) and 31–40 years [17.8 cells per cubic millimeter per year (5.1–30.5)].
Results
We identified 13,543 newly presenting patients who enrolled in the HIVRN between 2003 and 2011: 7200 between 2003 and 2007 and 6343 between 2008 and 2011. The median number of new patients was 1370 per year over the interval 2003–2007 and 1582 per year over the interval 2008–2011 (P = 0.142). The median number of new patients per year for whites was 401.5 during 2003–2007 and 382 during 2008–2011 (P = 0.54), for blacks it was 641.5 during 2003–2007 and 791 during 2008–2011 (P = 0.086), and for Hispanics it was 285 during 2003–2007 and 309 during 2008–2011 (P = 0.806). Patient characteristics stratified by time period appear in Table 1 (Fig. 1).
(Enlarge Image)
Figure 1.
Mean and predicted mean CD4 count at enrollment among new presenters from 2003 to 2011 with the corresponding 95% CI. *Solid lines denote mean CD4 count at enrollment predicted by the MLR model (Table 3) for all new presenters. The dashed lines denote the actual mean CD4 count at enrollment for all new presenters. Enrollment CD4 was predicted for each subject using the adjusted MLR (Table 3), and the mean of the predicted enrollment CD4 was plotted for each enrollment year. As the inputs to the model (the demographic and behavioral risk composition of the underlying cohort) vary from year to year, the mean predicted CD4 may not be perfectly linear when plotted against calendar year.
Overall, the median CD4 at enrollment rose from 285 to 317 cells per cubic millimeter between 2003–2007 and 2008–2011 (P < 0.001) (results not shown). Median CD4 counts for 2003–2007 and 2008–2010 stratified by demographics are shown in Table 2 .
The percentage of newly presenting subjects with CD4 at enrollment ≥350 cells per cubic millimeter increased from 40.8% in 2003–2007% to 44.3% in 2008–2011 (χ = 19.7, P < 0.001). There was no increase in the mean percentage of subjects with CD4 ≥350 cells per cubic millimeter during 2003–2007 (-0.19% [95% confidence interval (CI) -0.90% to 0.52%]), but there was an increase of 1.45% per year (0.73%, 2.16%) from 2008 to 2011 (results not shown).
The unadjusted annual mean CD4 at enrollment did not significantly increase over the interval 2003–2007 (-1.8 cells per cubic millimeter per year, 95% CI -5.7 to 2.2) but increased by 12.3 cells per cubic millimeter per year (95% CI 8.5 to 16.1) over the interval 2008–2011, for an overall mean increase in CD4 per year of 14.1 cells per cubic millimeter per year (7.1, 21.0) (results not shown). After adjusting for demographic factors and clinic site, the annual mean CD4 at enrollment did not significantly increase interval 2003–2007 but did significantly increase by 11.2 cells per cubic millimeter per year (7.4, 14.9) over the interval 2008–2011 ( Table 3 ). The difference in the slope was 13.3 cells per cubic millimeter per year (6.4, 20.1) comparing 2003–2007 with 2008–2011. Females had a higher CD4 at enrollment than did males ( Table 3 ). Variations by age, race/ethnicity, and HIV risk are addressed in the following section.
Demographic Variations in CD4 Trends
Race/Ethnicity. In 2003, the adjusted mean CD4 at enrollment was 69.3 cells per cubic millimeter (28.5, 110.0) greater in whites than in blacks, 69.2 cells per cubic millimeter (25.6, 112.8) greater in whites than in Hispanics, and not significantly different between blacks and Hispanics. In 2011, the adjusted mean CD4 at enrollment was 49.3 cells per cubic millimeter (13.6, 83.0) greater in whites than in blacks, 59.0 cells per cubic millimeter (17.8, 100.2) greater in whites than in Hispanics, and not significantly different between blacks and Hispanics.
The difference in the slope between 2003 and 2007 and 2008 and 2011 was 19.3 cells per cubic millimeter per year (5.9, 32.8) for whites and 10.8 cells per cubic millimeter per year (0.9, 20.6) for blacks, but there was no significant increase in Hispanics (11.3 cells per cubic millimeter per year [-2.3, 24.9]) or OTH race [16.2 cells per cubic millimeter per year (-23.0, 55.4)] (Fig. 2 and Table 4).
(Enlarge Image)
Figure 2.
Mean and predicted mean CD4 count at enrollment among new presenters from 2003 to 2011 stratified by race/ethnicity (panel A) and age category (panel B). *Solid lines denote the mean CD4 count at enrollment predicted by the MLR model (Table 4) for all new presenters, stratified as indicated. The dashed lines denote the actual mean CD4 count at enrollment for all new presenters, stratified as indicated. Other race is not shown. Enrollment CD4 was predicted for each subject using the adjusted MLR (Table 4), and the mean of the predicted enrollment CD4 was plotted for each enrollment year. As the inputs to the model (the demographic and behavioral risk composition of the underlying cohort) vary from year to year, the mean predicted CD4 may not be perfectly linear when plotted against calendar year.
HIV Risk. In 2003, the adjusted mean CD4 at enrollment was 79.3 cells per cubic millimeter (45.0, 113.6) greater in MSM than in heterosexual risk, 70.8 cells per cubic millimeter (10.7, 130.9) greater in IDU than in heterosexual risk, and not significantly different between MSM and IDU. In 2011, the adjusted mean CD4 at enrollment was 45.2 cells per cubic millimeter (12.7, 77.7) greater in MSM than in heterosexual risk and not significantly different between either MSM and IDU or IDU and heterosexual risk.
MSM and heterosexual risk groups had an increase in the slope of CD4 at enrollment per year over the interval 2008–2011 (Table 4). There was no increase in the slopes of CD4 at enrollment per year among IDU and other HIV risk categories over the interval 2008–2011 (Table 4).
Age. For those aged >30 years, age categories did not differ in adjusted mean CD4 at enrollment in 2003. In 2003, subjects aged ≤30 years had an adjusted CD4 at enrollment greater than subjects in age categories 31–40 years [69.1 cells per cubic millimeter (30.4, 107.8)], 41–50 years [82.5 cells per cubic millimeter (40.7, 124.2)], and >50 years [72.5 cells per cubic millimeter (-13.8, 158.9)—not significant]. In 2011, the adjusted mean enrollment CD4 was 63.4 cells per cubic millimeter (17.5, 109.3) greater in 31–40 years than in >50 years, but not significantly different between either 31–40 and 41–50 years or 41–50 and >50 years. However, the adjusted 2011 mean enrollment CD4 in subjects ≤30 years was greater than in subjects in age categories 31–40 years [52.1 cells per cubic millimeter (16.0, 88.3)], 41–50 years [79.9 cells per cubic millimeter (41.8, 117.9)], and >50 years [115.5 cells per cubic millimeter (72.2, 158.8)].
CD4 at enrollment increased per year over the interval 2008–2011 for age categories ≤30, 31–40, 41–50 years, but not for >50 years (Fig. 2 and Table 4). Compared with age category >50 years, the CD4 at enrollment slope over the interval 2008–2011 was greater in age categories ≤30 years (13.4 cells per cubic millimeter per year [0.9–25.9]) and 31–40 years [17.8 cells per cubic millimeter per year (5.1–30.5)].