IJE Advance Access originally published online on September 29, 2005
International Journal of Epidemiology 2005 34(6):1250-1253; doi:10.1093/ije/dyi198
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Cochrane Column |
Cochrane Column
South African Cochrane Centre, Medical Research Council, PO Box 19070, Tygerberg 7505, South Africa. E-mail: taryn.young{at}mrc.ac.za
The aim of the Column is to highlight Cochrane systematic reviews of relevance to public health and to stimulate debate on relevance, feasibility, and acceptability. This issue calls attention to the effectiveness of lay health worker interventions in primary and community health care.
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The Cochrane Collaboration (http://www.cochrane.org) is an international, non-profit organization that prepares and disseminates up-to-date systematic reviews on the effects of health care interventions in order to help people make well-informed decisions. Systematic reviews aim to answer focused health care questions by systematically identifying and evaluating all relevant research studies and synthesizing their results.
If you are interested in contributing to the Cochrane Column or The Cochrane Collaboration, contact me at the South African Cochrane Centre.
Lay health workers in primary and community health care: Cochrane systematic review
* Corresponding author. Norwegian Knowledge Centre for Health Services, Postboks 7004 St Olavsplass, 0130 Oslo, Norway. E-mail: simon.lewin{at}mrc.ac.za
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Background |
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 Top Background MethodsResultsDiscussion and conclusions |
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Lay health workers (LHWs) are used widely to provide care for a broad range of health issues. However, little is known about the effectiveness of LHW interventions. This review aimed to assess systematically the effects of LHW interventions in primary and community health care.
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Methods |
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TopBackgroundMethodsResultsDiscussion and conclusions |
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Search strategy
We searched the Cochrane Effective Practice and Organisation of Care and Consumers and Communication specialized registers (till August 2001); the Cochrane Central Register of Controlled Trials (till August 2001); MEDLINE (1966 to August 2001); EMBASE (1966 to August 2001); Science Citations (till August 2001); CINAHL (1966 to June 2001); Healthstar (1975–2000); AMED (1966 to August 2001); and the Leeds Health Education Effectiveness Database and the reference lists of articles.
Selection criteria
Randomized controlled trials (RCTs) of any intervention delivered by LHWs (paid or voluntary) in primary or community health care and intended to promote health, manage illness, or provide support to patients. A ‘lay health worker’ was defined as any health worker delivering health care; trained in the context of the intervention; and having no formal health professional or paraprofessional tertiary certificate or degree. There were no restrictions on the types of consumers.
Data collection and analysis
Two authors independently extracted data and assessed study quality. Studies comparing similar interventions were grouped for analysis. Where feasible, the results of included studies were combined and an estimate of effect obtained.
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Results |
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TopBackgroundMethodsResultsDiscussion and conclusions |
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Forty-three RCTs, involving more than 210 000 people using the services of LHWs, met the inclusion criteria. These showed considerable diversity in the targeted health issue and the aims, content, and outcomes of interventions. Most were conducted by investigators working in high-income countries (n = 35), but nearly half of these trials focused on low-income and/or minority populations (n = 15). Study diversity limited meta-analysis to outcomes for five subgroups (n = 15 studies). Promising benefits in comparison with usual care were shown for LHW interventions to promote immunization uptake in children and adults, and LHW interventions to improve outcomes for infectious diseases (malaria and acute respiratory infections) (Table 1). LHWs increased the uptake of breastfeeding, both before 2 weeks, and between 2 weeks and 6 months post-partum, but none of these differences were statistically significant. The effect in promoting breast cancer screening uptake when compared with usual care was also not significant. For the remaining 29 studies, the outcomes were too diverse to allow statistical pooling.
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Discussion and conclusions |
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TopBackgroundMethodsResultsDiscussion and conclusions |
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LHWs show promising benefits in promoting immunization uptake and improving outcomes for acute respiratory infections and malaria, when compared with usual care. Health planners could, therefore, consider including LHWs within health service strategies in these areas. However, caution in interpreting these findings is needed as these subgroups included few studies and many of the studies had small sample sizes. For other health issues, there is insufficient evidence to justify recommendations for policy and practice. There is also insufficient evidence to assess the LHW training or intervention strategies, which are likely to be most effective. Further research is needed in these areas.
The full text of the review is available in The Cochrane Library: Lewin SA, Dick J, Pond P, Zwarenstein M, Aja G, van Wyk B, Bosch-Capblanch X, Patrick M. Lay health workers in primary and community health care. The Cochrane Database of Systematic Reviews 2005, Issue 1. Art. No.: CD004015 [GenBank] .pub2. DOI: 10.1002/14651858.CD004015.pub2.
Commentary: Lay health workers in primary and community health care
Department of Public Health and Policy, London School of Hygiene and Tropical Medicine, London, UK
There have been many studies undertaken of programmes using lay health workers (LHWs) or community health workers (CHWs), which have demonstrated their effectiveness in extending services to difficult-to-reach areas or delivering specific interventions to particular groups. However, evaluations of such programmes have often focused on outputs rather than outcomes, and few have been designed as randomized controlled trials. This is particularly true of the early programmes in low-income countries, where CHWs were part of the primary health care approach of the 1970s and early 1980s.
This review, therefore, gives a partial view of LHW programmes. By selecting randomized controlled studies that met the inclusion criteria, the review focuses largely on industrialized countries and on studies undertaken from the 1990s onwards (only 8 of 43 cover low-income countries). It is cautious regarding the effectiveness of LHWs, suggesting that evidence is stronger for some interventions than others. Such caution is understandable, given that the conclusion is often based on one or two studies per intervention, with small numbers of LHWs (the largest group is 150), giving a snapshot of an intervention at a particular point in time.
Such reviews are extremely helpful in providing an overview of evidence that is technically robust, for reviewing methodological quality, and for highlighting the areas that need research. But they are only a first step for those involved in making and implementing public health policy. What is needed is more analysis that throws light on the difficult policy questions which RCTs do not answer: What makes one LHW programme more effective than another? Is it a question of leadership, of resources, of the intervention itself—its ease of use, understanding, and immediacy? How far are such programmes transferable to other contexts (what works in Birmingham may not in Glasgow, let alone Johannesburg) or countries (many countries tried, and failed, to emulate China's ‘barefoot doctor’ programme—which China itself terminated as its macro-economic policy shifted). Can LHW programmes be expanded beyond one geographical area, one target group? What incentives or rewards are needed to sustain them over time? Two recommendations from the authors would go some way to helping provide some answers: one, to develop a coherent typology of LHW interventions; and two, to gather the global evidence on the effectiveness of LHW interventions. But the studies reviewed would have to cover at least four decades, and include non-RCTs and un-published literature. It would also be important to re-visit some of the larger programmes. There is much to do beyond providing evidence of effectiveness, and much more analysis is necessary to advance public policy.
Commentary: Lay health workers in primary and community health care
Department of International Health, Johns Hopkins Bloomberg School of Public Health, MD, USA
This review takes up the challenge of assessing the effectiveness of lay health workers (LHWs) to improve delivery of primary and community health care and the outcomes of this care. The authors point to the enormous growth in the use of LHWs throughout the world in spite of scant evidence of LHWs' effectiveness. With an extensive search of available literature, they were able to identify only five systematic reviews that examined interventions that involved LHWs—all concerned with work conducted in the US. This review, focused on randomized controlled trials (RCTs), is the first global effort.
For this review the authors established inclusion criteria, painstakingly laid out their search strategy for identifying studies, detailed the methods they used, described the studies included and excluded, and assessed the quality of the studies. They provide extensive tables and graphs detailing these characteristics. They have been highly systematic and, overall, the review is probably as good as is possible.
They emphasize the enormous diversity of activities carried out by LHWs and the great variety of circumstances under which they function. They identified 43 studies that met their criteria—35 in high-income countries—but the diversity limited meta-analysis to five subgroups (15 studies): breast cancer screening, immunization promotion, breast feeding promotion, and improved diagnosis or treatment for selected infectious diseases. The authors concluded that LHW interventions when compared with usual care showed promising benefits at least for some kinds of health care such as promoting the uptake of immunization and for improving outcomes for malaria and acute respiratory infections in children.
The review pointed out several methodological problems including identification of RCTs concerned with LHWs given that there is no accepted definition of LHWs, a great range in terminology used (over 40 such terms), and generally poor descriptions of the LHW interventions, their backgrounds, training and support, and of expected outcomes of these interventions. They also note that under some circumstances, LHWs may do more harm than good and call for more work examining costs, both direct and indirect, involved in the use of LHWs. Though quite comprehensive, they did not discuss issues of incentives and motivation, recruitment, longevity, or turnover of LHWs.
The main concern with this review is the enormous heterogeneity of the studies included. In the face of such heterogeneity, is it useful to ask about generic effectiveness of LHWs? In general I should think not. And attempts to do a meta-analysis would seem of little value. Nonetheless, this well-done review makes interesting points and certainly will help focus attention on both the potential usefulness and the limitations of LHWs. The principal recommendation was ‘an urgent need for the development of a coherent typology of LHW interventions that could help to guide research and practice in this field’.
Perhaps further endeavours concerning LHWs could focus on specific case studies that highlight what works and how that might be used by others rather than on further efforts at the more formalized, often artificially forced efforts involved with meta-analysis. The real value of this study is not so much the specific conclusions themselves, but rather for focusing attention on the many neglected issues involved in the use of LHWs.
Response to Walt and Morrow
1 Health Systems Research Unit, Medical Research Council of South Africa, South Africa
2 Department of Public Health and Policy, London School of Hygiene and Tropical Medicine, London, UK
3 Institute for Clinical Evaluative Sciences, University of Toronto, Toronto, Canada
We would like to thank Gill Walt and Richard Morrow for their thoughtful and useful comments on our review. We agree that this or any systematic review of the effectiveness of an intervention is only a first step in providing information for decision-making. Nonetheless, we would suggest that this systematic review of RCTs is valuable, and indeed essential, in that it attempts to answer a question central to the policy assessment of any health intervention: Can it work? Without this information, there is, first, little point in asking questions of applicability, political will and so forth and, second, a danger that scarce resources may be wasted on ineffective interventions.
We shared Morrow's concerns regarding the heterogeneity of the included studies—a reflection of the diversity of health issues targeted by LHW programmes and the wide range of contexts in which these programmes have been implemented. We addressed this in part by the careful grouping of studies and by also selecting for meta-analysis only those subgroups in which both the interventions and the outcomes were sufficiently similar. We would argue, though, that a broad review of the effectiveness of LHWs is valuable for several reasons. First, for some health issues the review indicates that LHW interventions are effective—this is useful information for policy makers. Second, the review indicates gaps in knowledge that are unlikely to have been identified by reviews focusing on LHW interventions for specific health issues, such as immunization uptake. Third, the review highlights the extent to which researchers in particular speciality areas are working in isolation from one another, thereby failing to communicate adequately their experience and insights from research on the wide range of LHW programmes implemented in both low-income and high-income settings. This may result in duplication of effort and also slow the development of the field.
We are attempting currently to develop a typology of LHW interventions and would welcome the participation of others in this endeavour. We would also encourage other researchers to take up the suggestions from Walt and Morrow for further reviews of studies of LHW programmes to address the wide range of important policy questions that cannot be addressed by systematic reviews of RCTs.
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Notes |
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A summary of Cochrane reviews (and protocols) of relevance to health promotion and public health can be viewed on the Cochrane Health Promotion and Public Health website: http://www.vichealth.vic.gov.au/cochrane/
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