The use of MLPs to meaningfully address hardships that compound quality of life has been recognized across many peer-reviewed publications.(15, 28–35) However, little research has been done to evaluate the impact of MLPs in making measurable effects on the health harming needs of vulnerable, underserved populations. Thus, the primary goal of this systematic review was to synthesize the evidence on experimental MLP studies that have been conducted to date in adult and pediatric populations. This is the first systematic review to narrow in on the existence of MLP experimental studies and explore gaps in literature that could inform and shed ideas for successful MLP implementation and expansion across underserved populations. In this study, six experimental studies met the eligibility criteria, of which, most were of the quasi-experimental study design, having had no randomization to control group(24) or no control group at all.(22, 25, 26) Seen as the gold standard in establishing evidence of impact, experimental studies may test a treatment under rigorous standards to determine its potential effectiveness within preventative and clinical care settings.(36) The absence of many metrics, including lack of random allocation, lack of intent to treat analysis, and failure to report study power resulted in medium risk of bias for all, except the two RCT studies.(21, 27) Another challenge is that these studies were multi-modal and involved activities, like home visits and diabetes education, which complement legal services. While these programs offer a more holistic delivery of services, their well-integrated nature makes it difficult to isolate the effect of the provision of legal services. This review demonstrates that MLP interventions is not only a developing area of research that presents significant promise for implementation of innovative approaches, but an area that still demands high quality, rigorous RCTs to test the efficacy of MLPs for populations that need them the most. These findings highlight the need for organizations to transform into learning health systems, where delivery, training, and research activities are integrated, such that rigorous MLP evaluations are routinely incorporated into the implementation process.(37)
Most of our study populations were of lower socioeconomic status, belonged to a racial-ethnic minority group, belonged to families receiving governmental assistance for income and nutritional support, and were from homes headed by single parent households – in particular, women. In addition, most participants across the six studies presented numerous health harming needs; the most pressing and commonly mentioned included food and housing insecurity, unemployment, and government benefits. These findings are not any different from previous studies – both observational and experimental. (5, 10, 15, 28–35) Yet, despite the need for health and legal concerns to be addressed, the majority of the six studies -especially Ryan et al.2012 and Rosen et al. 2019- experienced significant loss to follow up particularly among Black and Hispanic participants.(25, 26) Studies targeting vulnerable populations are keenly aware of their populations’ exigent circumstances as well as their feelings about health care and legal providers.(38–42) Some of these circumstances and concerns may encompass the inability to schedule time off work, socioeconomic vulnerabilities (e.g. transient populations, lack of support, cultural and language barriers) and overall mistrust in the medical and legal communities.(11, 14, 38–42) The inability to retain participants not only impacts an intervention’s power to observe a desired effect but also hinders replication of ideas in larger scale studies that have the potential for broad and meaningful impact in vulnerable populations.(5) Furthermore, lack of retention in MLP implementation by these populations not only limits generalizability of results to the most intended and relevant populations, but also stymies the advancement of research and broadscale implementation that could ideally reduce health and social disparities in these communities. Indeed, interventionists must balance the provision of clinical and legal care with impactful community-based participatory research approaches that integrate the voices of community stakeholders and the very people who are recipients of these interventions.(5, 10) Finally, using implementation science methodologies and hybrid study designs to understand the predictors of implementation success of MLPs is warranted.(43)
One significant observation made about the selection of studies was their location. Specifically, none of these studies were conducted in southern or midwestern states. Research shows that the South, comprised of seventeen states (including Texas) and which is home to a significant share of the U.S. BIPOC population (Black, Indigenous, and People of Color), fares disproportionately poorer in health and socioeconomic metrics than northeastern and midwestern states.(44) Indeed, Southern U.S. residents are more likely to be overweight and obese, suffer from higher rates of chronic diseases, cancer, and infant mortality. These residents are also more likely to be uninsured, underinsured, and of lower socioeconomic status.(44) Given that this region of the country suffers disproportionately from health harming and social needs, MLPs have the potential to make transformational impacts in addressing population needs that may manifest as legal needs. Our research study speaks to the need to address the burden of care and legal needs that specific groups experience. Expanding the scope of MLPs will require rigorous scientific testing, greater interdisciplinary partnerships, investment of financial and social capital, advocacy, higher-level teaching across medical and legal institutions, and the support of community voices to tackle key determinants that contribute to widening health and socioeconomic disparities across the southern United States region.
Strengths and Limitations
This systematic review did have limitations that we must acknowledge. First, we only considered studies that were printed in English. Thus, it is possible that we may have overlooked medical legal partnership experimental studies that were conducted in other countries. Second, our review only included experimental studies; and while these designs are more scientifically rigorous in conduct, it is also probable that we may have neglected research studies that could have added to the richness of our systematic review. Despite these weaknesses, the strengths of our review are very much evident.
Strengths include an explicit focus on peer-reviewed experimental studies -both RCT and quasi-experimental, which are more superior in design and are more predictive of a treatment’s efficacy. Second, this study conducted an extensive search for peer-reviewed articles across multiple clinical, public health, and legal databases, with no limitation to place and year of publication. Third, we used the PRISMA guidelines to conduct our systematic review; additionally, this study is the first MLP systematic review to assess the methodological quality of studies using the CONSORT checklist. Lastly, this study used two independent reviewers to conduct, review and determine eligibility, and assess the quality of studies.