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Non-uptake of HAART among patients with a CD4 count <350 cells/mm3 - UK Collaborative HIV Cohort (CHIC). Catherine Kober Margaret Johnson Martin Fisher Caroline Sabin On behalf of UK-CHIC BHIVA/BASHH Manchester 2010. BACKGROUND. BACKGROUND.
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Non-uptake of HAART among patients with a CD4 count <350 cells/mm3 - UK Collaborative HIV Cohort (CHIC) Catherine Kober Margaret Johnson Martin Fisher Caroline Sabin On behalf of UK-CHIC BHIVA/BASHH Manchester 2010
BACKGROUND BACKGROUND • Since the introduction of highly active antiretroviral therapy (HAART) in 1996, treatment guidelines have evolved in terms of the CD4 count at which HAART should be initiated • Current British HIV Association (BHIVA) guidelines (2008) recommend that all patients with a confirmed CD4 count <350 cells/mm3 are offered HAART • In previous UK CHIC analyses, based on data up to 2003, only 50-60% of patients with a CD4 count <200 cells/mm3 and 10-15% with a CD4 count of 200-350 cells/mm3 initiated HAART in the following 6 months
BACKGROUND AIMS • To determine whether since the last UK-CHIC analysis, in 2004, the proportion of patients commencing HAART after a confirmed CD4 count < 350 cells/mm3 has improved • To identify factors associated with initiation (or not) of HAART after confirmed CD4 decline to <350 cells/mm3
BACKGROUND METHODS • Patients > 18 years of age in UK-CHIC included if: • Confirmed (2 consecutive) CD4 counts <350 • At least 1 day of subsequent follow-up • No previous ART • HAART: any regimen including a PI, NNRTI, abacavir or enfuvirtide • First analysis: all patients in UK-CHIC (1996 onwards) • Second analysis: patients with first confirmed CD4 <350 after 2004 • More than 6 months of follow-up • At least 1 clinic visit in 2007-2009
BACKGROUND ANALYSIS • Characteristics at time of first confirmed CD4<350 (baseline) and over follow-up were compared to identify factors associated with delayed HAART uptake • Demographic factors: gender, risk group, ethnicity • Clinical: previous AIDS diagnosis • Laboratory: CD4 count, viral load, frequency of CD4 monitoring (as surrogate of clinical attendance) • Analyses used proportional hazards regression with fixed (sex, age, risk group, ethnicity, AIDS, baseline CD4) and time-updated (frequency of CD4 measurement, % of CD4<350) covariates
RESULTS • 17,153 patients presented with their first confirmed low CD4 count <350cells/mm3 between 1996 and 2008 • Of this group 14,780 (86.2%) of patients initiated HAART a median of 5.1 months after the first confirmed low CD4 count
RESULTS • 17,153 patients presented with their first confirmed low CD4 count <350cells/mm3 between 1996 and 2008 • Of this group 14,780 (86.2%) of patients initiated HAART a median of 5.1 months after the first confirmed low CD4 count
RESULTS • 17,153 patients presented with their first confirmed low CD4 count <350cells/mm3 between 1996 and 2008 • Of this group 14,780 (86.2%) of patients initiated HAART a median of 5.1 months after the first confirmed low CD4 count
RESULTS • 17,153 patients presented with their first confirmed low CD4 count <350cells/mm3 between 1996 and 2008 • Of this group 14,780 (86.2%) of patients initiated HAART a median of 5.1 months after the first confirmed low CD4 count
RESULTS - Patients remaining under follow-up in 2007-2009 • 11,534 patients satisfied the following criteria: • first confirmed low CD4 count <350cells/mm3 between 1996 and 2008 • At least 6 months follow-up • At least one attendance during 2007-2009 (when BHIVA guidelines available advising treatment commenced for all patients with CD4<350cells/mm3 • 657 (5.6%) of patients had still not commenced HAART by the time they were last seen • Patient remaining off HAART: • had a median last available CD4 count 320 (IQR 258, 390) cells/mm3 • Among this subgroup, last CD4 count was:
RESULTS - Patients remaining under follow-up in 2007-2009 • Characteristics of patients started on HAART: • more likely to have experienced a previous AIDS diagnosis • 15.1% vs 4.6% p=0.0001 • had a lower first confirmed CD4 count <350cells/mm3 • median value 216 (IQR 99, 290) vs 300 (IQR 260, 324) p=0.0001 • had a longer duration of follow-up (months) after their low CD4 count • median 62.5 (IQR 31.4, 101.1) vs 24.1 (IQR 12.7, 45.3) p=0.0001 • attended clinic more frequently • total number of CD4 count measurements following confirmed low count - median 21 (IQR 12, 33) vs 10 (IQR 5, 19) p=0.0001 • mean time interval (days) between consecutive CD4 measures following confirmed low count – median 96 (IQR 77, 119) vs 114 (IQR 86, 161) p=0.0001
RESULTS - Patients remaining under follow-up in 2007-2009 • Graph showing the percentage of patients commenced on HAART by their last clinic visit in 2007-2009 stratified by year in which their first low CD4 count was recorded. All patients had >6 months follow-up
RESULTS - Patients with first low CD4 in 2004-2008 • 5613 patients were identified as having had a confirmed low CD4 <350 cells/mm3 from 2004-2008 • Of these, 534 (9.5%) had not started HAART by the time of their last clinic visit in 2007-2009 • Median baseline CD4 for the whole cohort was 230 [IQR 117, 300] cells/mm3
RESULTS - Patients with first low CD4 in 2004-2008 - Baseline covariates:
RESULTS - Patients with first low CD4 in 2004-2008 Results of multivariable proportional hazards regression analysis of factors associated with uptake of HAART (Fixed + time-updated covariates)
RESULTS - Patients with first low CD4 in 2004-2008 • After controlling for fixed and time-updated covariates, independent predictors for initiation of HAART included: • Older age of patient (RH /10 years older 1.11 [1.07, 1.14]) • A lower average CD4 count when considering the last two measurements taken (RH /50 cells/mm3 higher 0.56 [0.54, 0.57]) • A greater number of CD4 counts <350 cells/mm3 (RH /count 1.16 [1.14, 1.18]) • Risk group: Female heterosexuals (RH 1.10 [1.00, 1.21])were more likely to start • Intravenous drug users remained less likely to start HAART (RH 0.69 [0.56, 0.87]) • The association with the baseline CD4 count was reversed in the final analysis (RH /50 cells/mm3 higher 1.22 (1.18, 1.25)
Discussion • Patients presenting with first low CD4 count <350cells/mm3 between 1996 and 2008 • No real change in percentage of patients commencing therapy within the first 6 months after their low confirmed count over the years • 58.2% of patients commenced treatment within 6 months in 1998-1999 compared with 61% in 2006-2008 • A significant minority (5.6%) patients remain HAART naïve having presented with their first low CD4 count between 1996 and 2008 • 0.7% of patients remain HAART naïve having been diagnosed in 1996/1997 • 11.8% of patients remain HAART naïve having been diagnosed in 2006-2008 • Possible reasons for this - • Clinician factors: feel no rush to start, especially if CD4 count just less than 350cells/mm3 • Patient factors: takes >6 months to prepare/persuade patients that it is time to start. ?more reluctance to start straight away since guidelines changed to recommend life-long therapy (with no treatment breaks)
Limitations • Unable to determine whether HAART was offered and declined or whether HAART was not offered • Unable to determine whether co-morbidity (e.g. MTB or other OI) may have driven decision not to recommend HAART • Unable to determine if HAART was subsequently commenced at a non UK-CHIC site
Conclusion • Despite clear guidance regarding appropriate CD4 count below which to commence HAART, there remains a small but significant proportion of patients with a CD4 below this level who are treatment naïve. • Whilst it is not possible to state reasons for this, certain demographic groups are disproportionately affected • If there is a further shift towards earlier initiation of treatment (as in USA) these trends may become even more marked
Possible Future Analyses • Within UK-CHIC: • Analysis of those with CD4 >400 and >500 at diagnosis, with Kaplan Meier of proportion remaining HAART naïve (as in Stohr 2007) with comparison by calendar year • Analysis by treatment centre (anonymised) to tease out clinician versus patient factors • With other cohorts: • Comparison to other countries (?especially USA) • Outside of UK-CHIC: • Greater understanding of barriers to initiation within guidelines • RCT of intervention for “treatment refusers”