Patients who miss clinic appointments in the two years after
they enter HIV care take longer to suppress their viral load to undetectable levels
and also have a higher cumulative viral load than patients with high levels of
appointment attendance, US investigators report in the online edition of the Journal of Acquired Immune Deficiency
“Early retention in HIV care was associated with a time to
viral load suppression and two year cumulative viral load burden among patients
newly initiating HIV medical care,” write the investigators, who believe that
their findings have implications for both the prognosis of their patients and
the use of HIV treatment as prevention.
Few studies have explored the virological consequences of
clinic attendance in the years immediately following entry into HIV care.
Investigators from the HIV clinics at the University of Alabama and the
University of Washington believed that “sub-optimal early retention in care
represents a formidable obstacle to achieving HIV viral load suppression.”
They therefore designed a study involving 676 patients who entered
care at their clinics between 2007 and 2010. The investigators hypothesised
that missed appointments in the first two years after entering care would be
associated with delayed time to viral load suppression, and that patients who
had poorer levels of clinic attendance would have a higher cumulative viral
load over the two years of observation.
At the time of entry into care the patients had a median age
of 36 years, 44% were non-white males, and 36% were uninsured.
Median baseline viral load was approximately 40,000
copies/ml. A third of patients had an initial CD4 cell count below 200 cells/mm3,
with 43% having a count above 350 cells/mm3.
Overall, a quarter of patients failed to attend two or more
clinic appointments in their first two years of care.
A total of 79%
of patients started HIV therapy, and the median time to the initiation of
treatment was 35 days from entry into care. Approximately two-thirds of
individuals achieved an undetectable viral load, and the median time to
virological suppression was 308 days after the initial clinic visit.
Patients with private insurance (HR = 1.37 vs. uninsured;
95% CI, 1.08-1.73) and those with a baseline CD4 cell count below 200 cells/mm3
or 350 cells/mm3 (HR = 3.74; 95% CI, 2.83-4.95; HR = 2.95; 95% CI,
2.26-3.86) at baseline had a shorter time to virological suppression.
A higher baseline viral load (each 50,000 copies/ml, HR =
0.97; 95% CI, 0.96-0.99) and missed appointments (each “no show”, HR = 0.83;
95% CI, 0.76-0.92) were both associated with a longer interval between entry
into care and the achievement of an undetectable viral load.
Next the investigators looked at the impact of missed
appointments on cumulative viral load. Cumulative viral load fell as clinic
adherence increased (attendance up to 79% = 4.6 log10 copies x
years; 80% to 99% attendance = 4.3 log10 copies x years; 100%
attendance = 4.1 log10 copies x years; p < 0.001).
“Significantly greater viremia copy years, an estimate of
cumulative HIV burden, were accumulated among patients with poorer visit
adherence,” write the authors. “These findings have implications for patient
outcomes as recent studies have identified increased risk of deleterious
clinical events among patients experiencing greater cumulative viral load
burden over time.”
Statistical analysis showed that lower clinic attendance
(beta coefficient = 0.11 per 10% non attendance; 95% CI, 0.04-01.7) was
associated with higher cumulative viral load.
Restricting analysis to patients with a baseline CD4 cell
count below 350 cells/mm3 (the threshold for starting HIV treatment)
showed that patients who missed appointments took longer to suppress their
viral load (HR = 0.81 per additional “no show”; 95% CI, 0.72-0.92). Moreover, a
higher cumulative viral load was associated with poor clinic attendance for
these patients (beta coefficient = 0.14 per 10% visit adherence; 95% CI, 0.19-0.08).
“We identified significant associations between early
retention in care and viral load suppression among patients initiating
outpatient HIV medical care,” conclude the investigators. “We demonstrated the
importance of early visit adherence as it relates to cumulative HIV
burden…longitudinal measures of cumulative viral load burden, like viremia copy
years, may significantly contribute to the evaluation of test and treat HIV
prevention interventions, the success of which are predicated on both rapidly
achieving, and also longitudinally sustaining viral load suppression.”