*! version 4.0 28Aug2010 UNDER CONSTRUCTION

help for aidsprojVersion 4.08, 15Feb2011
dialog:

AIDS Burden Projection

aidsproj
[if exp]
[using filename ]
,
uptake:(pa_varname|pa_coef)
[
vintage:(vyear)
takeoff:(tyear)
horizon:(phorizon)
adrate1(####)
adrate2(####)
bdrate:(####)
fail1:(####)
erate:(####)
ndrate:(####)
incmult:(####)
strtcov2:(####)
trgtcov2:(####)
strtyr:(####)
trgtyr:(####)
complete
impute
countries:(clist)
regions:(rlist)
world
gr7
graph
grcombine
norescale
legend:(legend_options)
titlen(titlen_options)
titlec(titlec_options)
titlep(titlep_options)
titlee(titlee_options)
subtitle:(subtitle_options)
weo
saving:(filename, [replace])
]

Description

aidsproj uses input data on a cross-section of countrires in the
year prior to the "vintage year" of the data
to project several measures of the future disease and fiscal burden of
the AIDS epidemic on individual countries and on specified aggregates of
those countries. The program has one "required option", sets of options to describe
patient recruitment, the health benefits of treatment, the costs of treatment,
the incidence of new infections and a set of output options.

Input data file (on the `Main' tab of dialog)

The program must be fed a cross-country panel dataset containing
specific variables. The program assumes that this file will be supplied
by the using filename specification on the command line. That data set can be resident in memory when the
program is called or can be specified by using filename.

Required option (on the `ART Uptake' tab of dialog)

The program has only one required "option",
uptake:(pa_varname|pa_coef) , which
specifies the speed at which the countries in the projection will
increase their coverage of the unmet need for antiretroviral treatment.
The speed of uptake is specified as a "partial adjustment coefficient"
sigma, where 0 <= sigma <= 1 gives the proportion of
the unmet need for treatment who are enrolled for the first time
in antiretroviral therapy each year. The model assumes that, once enrolled
in treatment, a patient has a lifetime entitlement to treatment.
Those familiar with the "partial adjustment model" in applied
econometrics will recognize that sigma is related to the partial
adjustment coefficient lambda in that model by sigma = (1 - lambda).
The uptake parameter sigma is constant over time within
each country. It can be provided either as a variable pa_varname
which contains a single value for each country or as a constant
pa_coef which is then applied to all countries. For example,
specifying uptake(0.95) instructs aidsproj to
assume that in addition to treating all patients placed on treatment in
previous years who survive this year, all countries in the projection will in
each future year extend treatment to 95 % of those who are alive and need treatment.

Country inclusion criteria (on the `Main' tab of dialog)

complete|impute User can optionally sepcify either the
complete option or the impute option, but not both. Using
neither option allows aidsproj to perform some minor, relatively
innocuous imputations in order to add a few countries to the
projections. The complete option suppresses the countries for
which these innocuous imputations are required. The impute option
authorizes aidsproj to perform more daring imputations in order to
include more countries. As part of its routine output, aidsproj
tabulates the sample by the countries that are "complete" before any
imputations and those that are included by imputation.

The user can select subsets of countries for inclusion in global or
regional aggregates by using the if exp criterion.

Main options

vintage:(####) Vintage of data. Default is 2008

horizon:(phorizon) Specifies the last year to which
projections are computed. Default is 2020. Maximum is 2050.

takeoff:(ptakeoff) Specifies the first year for which
projections are displayed. Default is 2010. Maximum is 2050.

ART Uptake options

cd4(####) Median CD4 count at treatment initiation.
Default is 130. Choice of this parameter controls the first-year death-rate,
adrate1, the rate at which HIV+ convert to ART eligibility, erate,
and the death rate among ART eligible not on ART, ndrate.

adrate1(####) First year death rate on 1st
line ART. Default is an decreasing function of the CD4
option, but can be overidden by explicitly specifying the adrate1 value.

adrate2(####) Subsequent annual death rate on
1st line ART. Default is 0.04. Not affected by choice of CD4
parameter.

erate:(####) Rate at which HIV+ convert to
be eligible for ART. Default is an increasing function of the CD4
option, but can be overidden by explicitly specifying the erate value.

ndrate:(####) Death rate among ART
eligible not on ART. Default is a decreasing function of the CD4
option, but can be overidden by explicitly specifying the ndrate value.

2nd Line options

strtcov2:(####) Starting level of coverage
with 2nd line therapy. Default is 0.05.

trgtcov2:(####) Target level of coverage
with 2nd line therapy. Default is 0.95.

strtyr:(####) Starting year of coverage
with 2nd line therapy. Default is 200.

trgtyr:(####) Year target level to be
reached with 2nd line therapy. Default is 2020.

bdrate:(####) Annual death rate on 2nd
line ART. Default is 0.04.

Incidence options

iexog Incidence to follow an exogenous trend controlled
by the parameter incmult. On the `2nd Line/Incidence' tab of the
dialog box, check the box entitled `HIV incidence to follow an exogenous trend'.
The default, specified when iexog is absent, is for incidence to
be affected by the prevalence of HIV and by ART coverage.

incmult:(####) Multiple that each year's
incidence is of previous year. Default is 0.97. This parameter is ignored
unless the option iexog is specified.

ir0

pstrtyr(####)

ptrgtyr(####)

maxep(####)

maxcp(####)

vstrtyr####)

vtrgtyr####)

maxvp(####)

ve(####)

fp(####)

gp(####)

maxdt(####)

maxdu(####)

Cost options

cost(string)
rxc1lb(real 88)
rxc1ub(real 261)
rxc2lb(real 819)
rxc2ub(real 2634)
hsbedn(real 1.96)
hsvstn(real 9.5)
scale(real -0.146)
nonrxcaf(real 750)
DRate(passthru)
REFYear(passthru)

Output options

If no output options are specified, the program uses default
values of all the optional parameters, computes projections of the key
variables until the default horizon of 2020 and halts. If the user
specifies the option countries(clist), then for each country in
clist the program presents the projection results in tabular form.
If the user specifies the option world or regions(rlist),
the program computes the totals or averages for the specified
aggregate(s). Quantity or cost/expenditure projections are summed across
the specified group of countries while percentages or rates are
averaged. Averages are weighted by the number of people receiving
antiretroviral treatment in the given year in the respective countries
(not by their number of HIV infected, total populations or GDP).

The three default output sets are (1) the epidemiological
projections of the number of people under treatment, in need of
treatment and dying in each future year until the projection horizon;
(2) the average unit cost of treatment and the total cost of treatment;
(3) the proportion of annual expenditure that treats ongoing patients
(called the "entitlement") and the proportion that treats new patients
(called "discretionary"). If the weo option is specified, a fourth
set of projections compares the projected total expenditures on ART to
three projected national budgets which are projected under a no_ART
scenario using the
2007 World Economic Outlook.
The three budget categories used as comparators are total health
expenditures, central government public health expenditures and total
central government expenditures.

weo Adds comparisons to the World Economic Outlook's
projected expenditure categories to three other sets of projections. See
the previous paragraph.

countries:(clist) Use World Bank's
3-letter country names to specify countries for which results are
tabulated and, if graph options specified, displayed. Specified
countries must not conflict with the if criterion.

regions:(rlist) Use World Bank's 3-letter
region names to specify region aggregates for which results are
tabulated and, if graph options specified, displayed. Subject to the the
if criterion.

world Present tabulated results and, if graph options specified,
display global totals (or totals for all countries included by the
if criterion).

gr7 Display and save graphs in version 7 style: Fast but
crude.

graph Display and save graphs in version 9.2 style:
Slow and elegant.

grcombine Combines all 3 or 4 graphs into the panels
of a single graph. User must also specify either gr7 or
graph graphing method.

norescale Unless this option is specified, the
numeric values on the vertical axes of all graphs are rescaled to powers
of 10 that assure that the labels of the tick marks are less than four
digits. (Variables are returned to their unscaled units before
aidsproj exits. Rescaling uses my -rescale.ado- command.)

legend:(legend_options) Legend
suboptions are passed to the graph commands. Omitting the legend option
is the same as selecting legend(pos(12) ring(0)) so
that the legend appears above the graph and inside its boundaries.
Useful suboptions include:

off suppresses the legend
ring(0) places legend inside the graph boundaries
pos(3) places legend on right of graph
size(small) reduces the size of legend text
span stretches the legend box horizontally

The following options work only with option graph, not
with options gr7 or grcombine.

titlen(titlen_options) Replaces standard
title for quantity graphs. Specifying " " suppresses the title.

titlec(titlec_options) Replaces standard
title for cost graphs. Specifying " " suppresses the title.

titlep(titlep_options) Replaces standard
title for percent discretionary graphs. Specifying " " suppresses the
title.

titlee(titlee_options) Replaces standard
title for percent expenditure graphs. Specifying " " suppresses the
title.

subtitle:(subtitle_options) Replaces
standard subtitle for all graphs. Specifying " " suppresses the
subtitle.

Saving option

saving:(filename, [replace]) Specifies the
filename for the projections data file which the program then saves in
STATA's dta format, which is also the stub of the filename for
saved graphics files. If saving:(filename,
[replace]) is omitted, neither the data file of projections nor
the gph files are saved.

Examples

The following example generates projections of the worldwide
burden of the epidemic to the year 2020, using version 7 graphics. By
selecting the partial adjustment coefficient to equal 0.95, with the
option uptake(0.95), the scenario assumes that all
countries in the world will expand at 95 % of unmet need for ART each
year.

aidsproj using aidssub2007, uptake(.95) world gr7 grcombine

The following example changes only one epidemiologic
parameter, the assumption regarding the change in the rate of new cases
of HIV, or the incidence rate. Instead of the default assumption which
is that the number of new cases would decline by 5 % each year, this
example assumes that the rate of new cases would decline dramatically in
2007 by 90 % to only 10 % of its 2006 level and then continue to decline
by another 90 % every year. In other words it assumes that the rate of
new cases declines asymptotically to zero.

aidsproj using aidssub2007, uptake(.95) incmult(.10)
world gr7 grcombine

The following example produces the identical epidemmiological
predictions as the previous one, but presents different output. In
addition to output on all countries, it specifies output on the
individual countries in the World Bank's South Asia region, on the South
Asian Region as a whole and also, for comparison, on the Sub-Saharan
African region as a whole. All nine graphs are presented and saved, with names
beginning with the character string: "adj95_weo".

delimit ;

aidsproj using aidssub2007, uptake(.95) incmult(.10)
graph grcombine weo world countries(BGD BTN IND LKA NPL PAK)
regions(SAS SSA) saving(adj95_weo, replace) ;

delimit cr

Author

Mead Over,
Center for Global Development, Washington, DC 20036 USA. Email:
MOver@CGDev.Org if you observe any
problems.

References

Over, M., "Prevention Failure: The Ballooning Entitlement
Burden of U.S. Global AIDS Treatment Spending and What to Do About It"
Working Paper 144,
Center for Global Development, 2008.

Over, M., "Opportunities for presidential leadership on AIDS:
From an "Emergency Plan" to a Sustainable Policy," in N. Birdsall (ed.),
The White House and the World: A Global Development Agenda for the Next US President,
Center for Global Development, 2008, Chapter 11, pp. 299-326.

Over, M., "AIDS Treatment in South Asia: Equity and
Efficiency Arguments for Shouldering the Fiscal Burden When Prevalence
Rates Are Low"
Working Paper 161,
Center for Global Development, 2009.