Strengthening the public downstream SLD supply chain for MDR-TB : lessons learnt from a Western Cape case study

Coetzee, Elaan (2015-12)

Thesis (MEng)--Stellenbosch University, 2015.

Thesis

ENGLISH ABSTRACT: Systemic problems in the supply chain of second-line anti-TB drugs (SLDs) for multidrug-resistant tuberculosis (MDR-TB) are well documented and contribute significantly to the difficulties preventing successful control of the disease. Though literature contains a wealth of proposed changes to global SLD supply chain policies, there is a significant research gap related to quantitative modelling of the SLD supply chain to accurately predict the expected impact of these proposed changes on the availability and delivery of SLDs. The global SLD supply chain consists of two components: (i) the “upstream” component which includes all activities from the manufacturing of the active pharmaceutical ingredient through to the warehousing of drugs prior to shipment; and (ii) the “downstream” component which includes in-country warehousing and delivery of drugs to various healthcare facilities. In this research study, a downstream SLD supply chain is modelled using real-world data. The model is built for one SLD used in the MDR-TB treatment regimen, namely amikacin. This research forms part of a bigger study that will eventually incorporate both the upstream and the downstream components of the supply chain into a single model. A model of the current downstream segment of the supply chain for SLDs in the Western Cape was developed using a System Dynamics modelling approach. The model has been built and validated using real-world data provided by the Western Cape Department of Health (WCDoH). This model has been used as a platform for: (i) studying the behaviour and stability of the downstream component of the global SLD supply chain; and (ii) testing the impact of various supply chain policy changes that have been proposed. In addition to the modelling results, an analysis of the WCDoH data has also produced a number of insights into the function of the downstream supply chain, examples of these include: • 13% of SLDs ordered by the Cape Medical Depot (CMD) are only received more than three months after the order date by suppliers; and • 267% more units of amikacin than what is required on average are available at the CMD every month, leading to ineffective inventory management. The modelling results show that the factor that will most likely lead to the biggest improvement in the performance of the SLD supply chain is reduced lead time. Therefore, selecting suppliers that provide shorter lead times should be a priority. Furthermore, the results show that significant opportunities could be unleashed by adjusting the policy for determining the desired minimum and maximum levels of stock at the CMD. This research makes a contribution by: (i) increasing the understanding of the strengths and weaknesses of the SLD supply chain; (ii) quantitatively evaluating the expected impact of suggested changes to the global SLD supply chain; and (iii) proposing a methodology that can be used to model and evaluate other downstream medication supply chains.

AFRIKAANSE OPSOMMING: Sistemiese probleme in die voorsieningsketting van tweede lyn teenmiddels (SLDs) vir multi-weerstandbiedende tuberkulose (MDR-TB) is goed gedokumenteer en dra aansienlik by tot die voorkoming van die probleem en om die siekte suksesvol te beheer. Alhoewel literatuur menigte voorgestelde wysigings vir die globale SLD ketting beleide bevat, is daar ‘n beduidende navorsingsgaping wat verband hou met kwantitatiewe modellering van die SLD ketting. Dit lei daartoe dat die verwagte impak van hierdie voorgestelde wysigings aan die beskikbaarheid en die lewering van SLDs nie akkuraat kan voorspel word nie. Die globale SLD voorsieningsketting bestaan uit twee komponente: (i) die “stroomop” komponent wat alle aktiwiteite van die vervaardiging van die aktiewe farmaseutiese bestanddeel insluit tot by pakhuise van die teenmiddels voor dit versprei word; en (ii) die “stroomaf” komponent wat binnelandse pakhuise en aflewering van die teenmiddels na verskeie gesondheidsfasiliteite. In hierdie navorsingstudie is ‘n stroomaf SLD voorsieningsketting gemodelleer met behulp van werklike data. Die model is gebou vir een SLD wat gebruik word in die MDR-TB behandelingsstelsel, naamlik amikasien. Hierdie navorsing vorm deel van ‘n groter studie wat beide die stroomop en stroomaf komponente van die voorsieningsketting in ‘n enkele model inkorporeer. ‘n Model van die huidige stroomaf afdeling van die voorsieningsketting vir SLDs in die Wes-Kaap is ontwikkel deur ‘n Stelsel Dinamika Modellering benadering. Die model is gebou en bekragtig met behulp van werklike data wat deur die Wes-Kaapse Departement van Gesondheid (WKDvG) voorsien is. Hierdie model is gebruik as ‘n platform vir: (i) die bestudering van die gedrag en stabiliteit van die stroomaf komponent van die globale SLD voorsieningsketting; en (ii) om te toets wat die impak van verskeie voorgestel voorsieningsketting beleidsveranderinge is. Bykomend tot die modellering resultate, het ‘n ontleding van die WKDvG data ook ‘n aantal insigte van die funksie van die stroomaf voorsieningsketting geidentifiseer. Voorbeelde van hierdie sluit in: • 13% van SLDs wat bestel word deur die Kaapse Mediese Depot (CMD) word slegs meer as drie maande na die beveldatum deur verskaffers ontvang; en • 267% meer eenhede van amikasien as wat benodig word, word gemiddeld beskikbaar gestel deur die CMD elke maand, wat lei tot oneffektiewe bestuur van voorraad. Die modellering resultate toon dat die faktor wat waarskynlik sal lei tot die grootste verbetering in die doeltreffendheid van die SLD voorsieningsketting is, om lei tyd te verminder. Daarom moet die keuse van verskaffers wat korter lei tyd aanbied ‘n prioriteit wees. Verder toon die resultate dat beduidende verbeteringe geskep kan word deur die beleid vir die bepaling van die gekose minimum en maksimum vlakke van voorraad aan die CMD aan te pas. Hierdie navorsing lewer ‘n bydrae tot: (i) die verhoging van die begrip van die sterk- en swakpunte van die SLD voorsieningsketting; (ii) die kwantitatiewe evaluering van die verwagte impak van voorgestelde wysigings aan die globale SLD voorsieningsketting; en (iii) stel ‘n metode voor wat gebruik kan word om ander stroomaf medikasie voorsieningskettings te evalueer.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/97993
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