Research
Interest
In resource-limited
settings, policy makers frequently make
decisions about improving population
health through the use of new health
technologies despite the scarcity and
insufficiency of data to inform such
decisions. My research focuses on
applying mathematical modeling to
leverage scarce data in forecasting the
future burden of disease and in
evaluating the value of innovative
health technology in many contexts
including low- and middle-income
countries. In my dissertation, I
constructed simulation models that
represents temporal changes in heavy
drinking behaviors and features of
Hepatitis C virus epidemiology observed
in China where a rapidly growing economy
and healthcare system have accompanied
changes in population health.
Research in
Progress
- Age- and
Time-trend in Harmful Drinking
Behavior in China: Projecting Future
Burden and the Potential for
Intervention Benefit
This
study aims to understand how heavy
drinking behaviors among Chinese
men have changed in the past and
how they might change in the
future and assess potential health
benefit of intervening on heavy
drinking behavior in a target age
group. We constructed a simulation
model of changes in heavy drinking
behavior and calibrated the rates
of initiating and ceasing heavy
drinking in the model to the birth
cohort-specific prevalence of
heavy drinking by age. Our study
found that the risk of heavy
drinking is concentrated in the
middle-aged men in age 40s and
50s. We also projected a
continuing decline in prevalence
of heavy drinking in men in China
though with variation by age over
time. Lastly, the study highlights
that age-targeted interventions on
risk have the potential to
efficiently improve population
health.
- Calibration
to Cross-Sectional Data When Temporal
Trends Exist As Exemplified By Models
of Heavy Drinking in China
This study
illustrates how the assumption of no
temporal trends in risk behaviors
and disease epidemiology in model
calibration can lead to drastically
different calibrated parameters,
future burden projections, and
intervention effect estimates when
compared to calibration that employs
birth cohort-specific parameters. We
took the constructed model of heavy
drinking among Chinese men as an
example. We compared cross-sectional
and birth cohort calibration where
each approach has different
stratification in transition
parameters and the level of
granularity in calibration target.
More importantly, cross-sectional
approach took the cross-sectional
data as its calibration targets,
assuming no birth cohort trends in
heavy drinking over time. Our study
found that calibrating age-specific
parameters in a Markov Cohort model
under the assumption that temporal
trends do not exist yielded
different age patterns in the
parameter values compared to
calibration that accounted for
temporal trends in parameters. In
addition, consideration of temporal
trends in parameters improves the
model’s performance in predicting
future heavy drinking prevalence.
These findings highlight the impact
of temporal trend assumptions should
be examined carefully, especially
when the model is used to predict
future outcomes and the potential
effects of health interventions.
- Health
and Cost Impact of Scaling up
Management for Hepatitis C Virus (HCV)
Infections in China
Motivated
by the potential impact of
innovative but expensive
technologies on population health in
resource-limited settings, this
study aims to assess the value of
new hepatitis C virus (HCV)
treatments in the context of the
current healthcare delivery system
in China. China has the largest
number of people infected with HCV
of all countries in the world. It
first approved directly acting
antivirals to treat HCV in 2017.
Efficiently delivering these
treatments to this large group of
potential patients, many of whom
have not yet been identified via
screening and not all of whom will
benefit equally from treatment,
presents important health policy
questions. I have constructed a
microsimulation model of HCV
incidence and progression in China
that matches Chinese epidemiological
data which is stratified by drinking
behavior in terms of risks of
mortality and liver fibrosis
progression and which tracks
individuals’ HCV screening status. I
plan to use this model to evaluate
combinations of interventions aimed
at reducing heavy drinking,
increasing the fraction of
individuals with chronic HCV who are
screened and diagnosed, and
increasing treatment. I expect that
the value of interventions will
depend on: how they are targeted in
terms of characteristics like age;
in what combinations they are used
and at what intensity; and the
coverage and accuracy of risk factor
targeting and screening
interventions.
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