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HIV treatment guidelines and value of CD4 count at ART initiation: data analysis of a cohort of HIV patients enrolled in Italy when their CD4 count was >500 cells/mm3
Abstract Content:
Background: Aim was to evaluate the influence of guidelines changes on the probability of starting ART at different CD4+ levels in patients enrolled in ICONA in 1996-2010.
Methods: Patients with CD4 count>500 cells/mm3 at enrolment were included. We used the DHHS guidelines to define temporal cut-offs at which recommendations were modified (1996, 2000, 2002, 2003, 2004, 2008 and 2009). Patients' follow-up accrued-up from enrolment to date of starting ART or last follow-up. Person-years (PY) with CD4 count in pre-defined categories (< 200, 200-350, 350-500 and >500) and number of patients initiating ART at each level were counted. Poisson regression analysis was used to estimate relative rates of initiating ART at a certain level of CD4 and calendar period.
Results: We studied 2705 patients, median age 35 years, 29% females, 34% infected heterosexually, median CD4 count at enrollment 672 (range:501-1466) cells/mm3 and viral load (VL) 9,800 (IQR:1,800-34,920) copies/mL. PY at risk were: 25%(1996-1999), 19%(2000-2001), 10% (2002), 9%(2003), 25%(2004-2007), 5%(2008) 8%+(2009). Both current levels of CD4 count and VL showed strong gradients of association with the probability of starting ART: the rates were 93/%PY in patients with VL>100,000 vs. 7%/PY in those with VL< =10,000 copies/mL., 72/%PY in patients with CD4 count 200-350 vs. 20/%PY in those with 351-500 cells/mm3. The figure shows relative rates according to current CD4 levels and calendar periods.
[CD4 table]
Conclusion: we show an increased probability of initiating ART with a CD4 count 201-350/mm3 starting from 2008 and a low probability of starting ART at counts >500 cells/mm3 constant over time.
Methods: Patients with CD4 count>500 cells/mm3 at enrolment were included. We used the DHHS guidelines to define temporal cut-offs at which recommendations were modified (1996, 2000, 2002, 2003, 2004, 2008 and 2009). Patients' follow-up accrued-up from enrolment to date of starting ART or last follow-up. Person-years (PY) with CD4 count in pre-defined categories (< 200, 200-350, 350-500 and >500) and number of patients initiating ART at each level were counted. Poisson regression analysis was used to estimate relative rates of initiating ART at a certain level of CD4 and calendar period.
Results: We studied 2705 patients, median age 35 years, 29% females, 34% infected heterosexually, median CD4 count at enrollment 672 (range:501-1466) cells/mm3 and viral load (VL) 9,800 (IQR:1,800-34,920) copies/mL. PY at risk were: 25%(1996-1999), 19%(2000-2001), 10% (2002), 9%(2003), 25%(2004-2007), 5%(2008) 8%+(2009). Both current levels of CD4 count and VL showed strong gradients of association with the probability of starting ART: the rates were 93/%PY in patients with VL>100,000 vs. 7%/PY in those with VL< =10,000 copies/mL., 72/%PY in patients with CD4 count 200-350 vs. 20/%PY in those with 351-500 cells/mm3. The figure shows relative rates according to current CD4 levels and calendar periods.
[CD4 table]
Conclusion: we show an increased probability of initiating ART with a CD4 count 201-350/mm3 starting from 2008 and a low probability of starting ART at counts >500 cells/mm3 constant over time.