A realist evaluation of a clinic based lay health worker intervention to improve the management of hypertension in rural South Africa
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Date
2017
Authors
Limbani, Felix
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Abstract
1. Background
Hypertension prevalence is high in Africa and is one of the commonest cardiovascular
ailments. A cluster randomized control trial (RCT) was run in the Bushbuckridge sub-district,
Mpumalanga, in South Africa, to test whether lay health workers (LHW), working alongside
nurses in rural clinics can improve management of hypertension. The trial’s programme
theory was thus management of hypertension would improve since LHWs would free up
nurses by taking up some of their tasks. Nurses would then focus on clinical management of
the patients. In this area, nearly half of adults are hypertensive, but only 9% have the blood
pressure well controlled.
In my PhD, I have used realist evaluation approach to understand the impact of the LHWs
and explain “what worked for whom, under what conditions and how”. I have also discussed
the practicality of combining realist evaluations and RCTs, contributing to an ongoing
debate.
2. Aims
To understand under what context and through what mechanisms a clinic based lay health
worker intervention will enhance integrated chronic care for hypertensive patients and will
modify patient outcomes in a cluster randomized trial in primary health care clinics.
3. Methods
This study was a theory driven realist evaluation. It was based in realism approach which
focused on explaining “why” and “how” improvements happened (or not). I used Medical
Research Council’s (MRC) framework for process evaluation of complex interventions to
understand and present how the different constituents of the intervention, implementation,
context, mechanisms and outcomes are interconnected. My programme theory was
adapted from Pawson and Tilley’s realist approach that considered outcomes from the
intervention, as a configuration of the context and the mechanisms through which the
intervention was implemented (context + mechanisms = outcomes). I also used other
theories that describe factors for ideal chronic care (Wagner model) and effects of
complexity in organizations (theory of complex adaptive system).
I used a case study approach to compare and contrast experiences in the eight case clinics.
The intervention and operation of the clinics were explored over time during the pre-trial
period, during the preparation and development phase of the intervention, mid-way
through the implementation of the intervention and towards the closure of the trial. Data
collected was largely qualitative using detailed, observation of clinic activities and patient
pathway, focus group discussions with community health workers and community
members, semi-structured interviews Clinic Managers, Clinic Supervisors and sub-District
Manager, in-depth interviews with LHWs and the Implementation Manager, semi-structured
interviews with three cohorts of purposively selected hypertensive patients in their homes,
patient exit structured interviews, and Implementation Manager’s and researcher diaries.
Qualitative data was analyzed using Nvivo and data extraction sheets that pulled together
data from different sources. Quantitative data from patient exit structured interviews was
analyzed descriptively using simple statistical tests.
4. Findings
At the time of the study, implementation of a government initiative called Integrated
Chronic Disease Management (ICDM) model was underway in all clinics. There was rapidly
increasing demand for chronic disease care as HIV management and management of stable
chronic patients was referred down from hospitals to clinics. The trial clinics were swamped
by HIV and hypertensive patients with 53% of the clinic visits by patients with chronic
diseases done by HIV patients and 47% done by hypertensive patients. More support is
available for HIV patients as compared with hypertensive patients such as tracing of patients
that default treatment, counselling and testing by lay counsellors and data capturing.
Clinics were affected by constant break down of BP machines and cuffs that were torn.
There was limited maintenance of equipment and supply of materials i.e. patient files and
packs for prepacking medication. Supply of hypertension drugs increasingly became erratic
in all clinics. There was perceived shortage of nurses with some clinics being better off than
others. Limited space and dilapidated Infrastructure affected chronic pathways in some
clinics. Clinic management differed from clinic to clinic which affected relations among staff,
relationship between staff and patients, and day to day operation of the clinic. Performance
and motivation among LHWs varied across clinics and largely depended on support from
other clinic staff.
LHWs had background in community health work, were residents of villages served by
respective clinics and had attained grade 12 (Matric). LHWs supported the nurses with
appointment booking, pre-retrieval of files and filing back, measuring blood pressure, health
education and prepacking of medication. They also reminded hypertensive patients prior to
their appointment and followed up with those that missed appointment. The LHWs were
supervised by an Implementation Manager who was a Professional Nurse by training. During
the intervention, LHWs played an important role of identifying and following up with acute
and other chronic patients with raised blood pressure.
I placed the clinics into well, medium and poor functioning categories, although there was
no clear cut difference between well and medium functioning clinics, and between medium
and poor functioning clinics. However, my analysis showed that clinics require at least one
of the following: strong management, teamwork, or a committed chronic care nurse, to get
reasonable outcomes. If none of these exist, clinics perform poorly.
5. Discussion and conclusion
The LHW programme theory partially worked as expected. The intervention was not
successful in improving population levels of BP but successfully changed the functioning of
clinics and delivery of care to patients with chronic diseases. The success in improving
functioning of clinics varied across the intervention clinics. The LHW programme theory has
explained the causal pathways that led to these differences in the programme outcomes
and effects. These were mainly as a result of differences in context, mechanisms and
implementation process.
Using the MRC framework for process evaluation of complex interventions, the following
configuration of intervention, context and mechanisms explains the study: Clinics with
observed better contextual factors i.e. infrastructure, equipment, good clinic management,
nurse levels, low patient loads; were clinics with positive effects in the work of the LHWs i.e.
appointment booking, reminding and following up with patients, prepacking medication and
filing. These were also clinics where staff related well among themselves and with patients,
supported the work of LHWs and had motivated and skilled LHWs. Such clinics had positive
clinic level proximal outcomes (collected through clinic link) that included patients adhering
to their appointment dates and identifying patient with raised BP.
Use of theories in this study has helped me to understand that health care facilities are
complex organizations and are always evolving and changing. A complex mix of different
factors i.e. relations, management, resources, resulted in no linear path of implementation
and outcomes. Chronic care depends on positive interaction between the health system, the
providers and the users. When carrying out health care interventions, implementers should
consider the unique nature of facilities and strengthen the interactions between the health
system, the providers and the users.
I support the notion that realist evaluations can be used with RCTs and can be used to
explain and strengthen findings from the trial. Trials should routinely include a process
evaluation which should describe the context in detail and review how the contexts of the
trial affect the implementation and outcomes, while understanding the mechanisms by
which the intervention works.
LHWs provided useful support to nurses in providing integrated care for chronic patients
compared to usual clinics. However, the effectiveness of LHWs was affected by limited
resources, increasing patient load and poor clinic management. The realist evaluation has
reflected on policy and practice implications for effective chronic disease management.
Such issues include, (a) lay persons can take up socially and medically oriented tasks of
nurses with proper selection, training and supervision, (b) measuring vital signs for every
patient that comes to the clinic has left the BP machines overwhelmed and often broken
down, (c) despite introduction of integrated chronic disease management, programmes are
still implemented vertically at clinic level with special attention given to HIV. The innovative
methodological contribution in this PhD has been this additional level of information about
the causal pathway in implementing the LHW intervention which otherwise could not have
been identified just with a randomized controlled trial.
Description
A thesis submitted for the degree: Doctor of Philosophy
School of Public Health
Faculty of Health Sciences
University of the Witwatersrand, Johannesburg., 2017
30 October 2017.
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Citation
Limbani, Felix, (2017) A realist evaluation of a clinic based lay health worker intervention to improve the management of hypertension in rural South Africa, University of the Witwatersrand, Johannesburg, https://hdl.handle.net/10539/25615