Thesis (MEng)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: South Africa has a severe HIV (human immunodeficiency virus) burden and
the management of the disease is a priority, especially in the public healthcare
sector. One element of managing the disease, is determining when to
initiate an HIV positive individual onto anti-retroviral therapy (ART), a
treatment that the patient will remain on for the remainder of their lifetime.
For the majority of HIV positive individuals in the country, this
decision is governed by the results of a CD4 (cluster of differentiation 4)
test that is performed at set time intervals from the time that the patient
is diagnosed with HIV until the patient is initiated onto ART. A device
for CD4 measurement at the point of care (POC), the Alere PIMA™, has
recently become commercially available. This has prompted a need to evaluate
whether CD4 testing at the POC (i.e. at the patient serving healthcare
facility) should be incorporated into the South African public healthcare
sector's HIV diagnostic service provision model.
One challenge associated with the management of HIV in the country is the
relatively large percentage of patients that are lost to follow-up at various
points in the HIV treatment process. There is extensive evidence that
testing CD4 levels at the POC (rather than in a laboratory, as is the current
practice) reduces the percentage of patients that are lost to follow-up before
being initiated onto ART. Therefore, though POC CD4 testing is more
expensive than laboratory-based CD4 testing, the use of this technology in
South Africa should be investigated for its potential to positively influence
health outcomes.
In this research, a multi-objective location science model is used to generate
scenarios for the provision of CD4 testing capability. For each scenario,
CD4 testing provision at 3 279 ART initiation facilities is considered. For
each facility, either (i) a POC device is placed at the site; or (ii) the site's testing workload is referred to one of the 61 CD4 laboratories in the country.
To develop this model, the characteristics of eight basic facility location
models are compared to the attributes of the real-world problem in order to
select the most suitable one for application. The selected model's objective,
assumptions and inputs are adjusted in order to adequately model the realworld
problem. The model is solved using the cross-entropy method for
multi-objective optimisation and the results are verified using a commercial
algorithm.
Nine scenarios are selected from the acquired Pareto set for detailed presentation.
In addition, details on the status quo as well as a scenario where
POC testing is used as widely as possible are also presented. These scenarios
are selected to provide decision-makers with information on the range
of options that should be considered, from no or very limited use to widespread
use of POC testing. Arguably the most valuable contribution of
this research is to provide an indication of the optimal trade-off points
between an improved healthcare outcome due to POC CD4 testing and
increased healthcare spending on POC CD4 testing in the South African
public healthcare context. This research also contributes to the location
science literature and the metaheuristic literature. / AFRIKAANSE OPSOMMING: Suid-Afrika gaan gebuk onder `n swaar MIV- (menslike-immuniteitsgebreksvirus-)
las en die bestuur van die siekte is `n prioriteit, veral in die openbare
gesondheidsorgsektor. Een element in die bestuur van die siekte is om te
bepaal wanneer `n MIV-positiewe individu met antiretrovirale- (ARV-)behandeling
behoort te begin, waarop pasiënte dan vir die res van hul lewens
bly. Vir die meeste MIV-positiewe individue in die land word hierdie besluit
bepaal deur die uitslae van `n CD4- (cluster of differentiation 4-)toets wat
met vasgestelde tussenposes uitgevoer word vandat die pasiënt met MIV
gediagnoseer word totdat hy of sy met ARV-behandeling begin. `n Toestel
vir CD4-meting by die punt van sorg (\POC"), die Alere PIMA™, is onlangs
kommersieel beskikbaar gestel. Dit het `n behoefte laat ontstaan om
te bepaal of CD4-toetsing by die POC (met ander woorde, by die gesondheidsorgfasiliteit
waar die pasiënt bedien word) by die MIV-diagnostiese
diensleweringsmodel van die Suid-Afrikaanse openbare gesondheidsorgsektor
ingesluit behoort te word.
Een uitdaging met betrekking tot MIV-bestuur in die land is die betreklik
groot persentasie pasiënte wat verlore gaan vir nasorg in die verskillende
stadiums van die MIV-behandelingsproses. Heelwat bewyse dui daarop dat
die toetsing van CD4-vlakke by die POC (eerder as in `n laboratorium, soos
wat tans die praktyk is) die persentasie pasiënte wat verlore gaan vir nasorg
voordat hulle met ARV-behandeling kan begin, verminder. Daarom, hoewel
CD4-toetsing by die POC duurder is as toetsing in `n laboratorium, behoort
die gebruik van hierdie tegnologie in Suid-Afrika ondersoek te word.
In hierdie studie is `n meerdoelige liggingswetenskapmodel gebruik om scenario's
vir die voorsiening van CD4-toetsvermoë te skep. Vir elke scenario
word CD4-toetsvermoë by 3 279 ARV-inisiasie fasiliteite oorweeg. Vir elke
fasiliteit word toetsvermoë verskaf deur (i) die plasing van POC-toestelle by die fasiliteit, of (ii) verwysing vir laboratoriumgebaseerde toetsing by een
van die 61 CD4-laboratoriums in die land. Die kenmerke van agt basiese
fasiliteitsliggingsmodelle is met die kenmerke van die werklike probleem
vergelyk om die mees geskikte model vir toepassing op die werklike probleem
te bepaal. Die doelwitte, aannames en insette van die gekose model
is daarna aangepas om die werklike probleem voldoende te modelleer. Die
model is opgelos met behulp van die kruis-entropie-metode vir meerdoelige
optimering, waarna die resultate deur middel van `n kommersiële algoritme
bevestig is.
Nege scenario's uit die verworwe Pareto-stel word uitvoerig aangebied. Daarbenewens
beskryf die studieresultate die besonderhede van die status quo
sowel as `n scenario waar POC-toetsing so wyd moontlik gebruik word. Hierdie
scenario's word aangebied om besluitnemers van inligting te voorsien
oor die verskeidenheid moontlikhede wat oorweeg kan word, wat wissel van
geen of baie beperkte tot wydverspreide gebruik van POC-toetsing. Die
mees beduidende bydrae van hierdie navorsing is stellig dat dit `n aanduiding
bied van die optimale kompromie tussen `n verbeterde gesondheidsorguitkoms
weens CD4-toetsing by die POC, en verhoogde gesondheidsorgbesteding
aan CD4-toetsing by die POC, in die konteks van Suid-Afrikaanse
openbare gesondheidsorg. Die navorsing dra ook by tot die ligingswetenskapliteratuur
sowel as tot die metaheuristiekliteratuur.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/96972 |
| Date | 03 1900 |
| Creators | Oosthuizen, Louzanne |
| Contributors | Bekker, James, Stellenbosch University. Faculty of Engineering. Dept. of Industrial Engineering. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 174 pages : illustrations |
| Rights | Stellenbosch University |
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