Background: In addition to evidence of effectiveness, review users often require information on the equity impacts of interventions; the extent to which interventions can be applied in other settings and whether similar effects might be expected (applicability); and factors likely to influence scaling up. However, these issues are often not discussed by review authors.

Objectives: To assess the extent to which evidence is available to facilitate assessment of applicability, scaling up and equity issues from RCTs included in a review of the effects of lay health workers (LHWs) for chronic conditions.

Methods: For each included RCT, data was extracted on intervention context and on the groups targeted by the intervention, including their geographic, demographic and socio-economic details. We used these data to consider issues of applicability, scaling up and equity.

Results: Overall, the included studies provided little data regarding the differential effects of the interventions across different populations making equity effects difficult to assess. Most studies were undertaken in high income countries and it is not clear whether the effects could be transferred to other settings with different health care systems. However, most of these studies were directed at low income or ethnic minority groups in these settings. To the extent that these groups share similar constraints in accessing health care with service users in low- and middle-income countries (LMICs), the interventions may be applicable in LMICs. Consideration of factors affecting the scaling up of the interventions was limited by poor intervention descriptions.

Conclusions: Assessing applicability, scaling up and equity issues for effective interventions continues to be hampered by limited data in trial reports. Guidance for trialists on the reporting of such data needs to be applied.