Defining and measuring health equity in research on task shifting in high-income countries: A systematic review

INTRODUCTION: Task shifting interventions have been implemented to improve health and address health inequities. Little is known about how inequity and vulnerability are defined and measured in research on task shifting. We conducted a systematic review to identify how inequity and vulnerability are identified, defined and measured in task shifting research from high-income countries. METHODS AND ANALYSIS: We implemented a novel search process to identify programs of research concerning task shifting interventions in high-income countries. We searched MEDLINE, Embase, CINAHL, PsycINFO, Web of Science, and CENTRAL to identify articles published from 2004 to 2016. Each program of research incorporated a "parent" randomized trial and "child" publications or sub-studies arising from the same research group. Two investigators extracted (1) study details, (2) definitions and measures of health equity or population vulnerability, and (3) assessed the quality of the reporting and measurement of health equity and vulnerability using a five-point scale developed for this study. We summarized the findings using a narrative approach. RESULTS: Fifteen programs of research met inclusion criteria, involving 15 parent randomized trials and 62 child publications. Included programs of research were all undertaken in the United States, among Hispanic- (5/15), African- (2/15), and Korean-Americans (1/15), and low socioeconomic status (2/15), rural (2/15) and older adult populations (2/15). Task shifting interventions included community health workers, peers, and a variety of other non-professional and lay workers to address a range of non-communicable diseases. Some research provided robust analyses of the affected populations' health inequities and demonstrated how a task shifting intervention redressed those concerns. Other studies provided no such definitions and measured only biomedical endpoints. CONCLUSION: Included studies vary substantially in the definition and measurement of health inequity and vulnerability. A more precise theoretical and evaluative framework for task shifting is recommended to effectively achieve the goal of equitable health.