Quasi-experimental study designs series–paper 12: strengthening global capacity for evidence synthesis of quasi-experimental health systems research

Systematic Review Reveals Lack of Causal Methodology Applied to Pooled Longitudinal Observational Infectious Disease Studies

OBJECTIVES

Among ID studies seeking to make causal inferences and pooling individual-level longitudinal data from multiple infectious disease cohorts, we sought to assess what methods are being used, how those methods are being reported, and whether these factors have changed over time.

STUDY DESIGN AND SETTING

Systematic review of longitudinal observational infectious disease studies pooling individual-level patient data from 2+ studies published in English in 2009. 2014, or 2019. This systematic review protocol is registered with PROSPERO (CRD42020204104).

RESULTS

Our search yielded 1,462 unique articles. Of these, 16 were included in the final review. Our analysis showed a lack of causal inference methods and of clear reporting on methods and the required assumptions.

CONCLUSION

There are many approaches to causal inference which may help facilitate accurate inference in the presence of unmeasured and time-varying confounding. In observational ID studies leveraging pooled, longitudinal IPD, the absence of these causal inference methods and gaps in the reporting of key methodological considerations suggests there is ample opportunity to enhance the rigor and reporting of research in this field. Interdisciplinary collaborations between substantive and methodological experts would strengthen future work.

Integrating HIV services and other health services: A systematic review and meta-analysis

BACKGROUND

Integration of HIV services with other health services has been proposed as an important strategy to boost the sustainability of the global HIV response. We conducted a systematic and comprehensive synthesis of the existing scientific evidence on the impact of service integration on the HIV care cascade, health outcomes, and cost-effectiveness.

METHODS AND FINDINGS

We reviewed the global quantitative empirical evidence on integration published between 1 January 2010 and 10 September 2021. We included experimental and observational studies that featured both an integration intervention and a comparator in our review. Of the 7,118 unique peer-reviewed English-language studies that our search algorithm identified, 114 met all of our selection criteria for data extraction. Most of the studies (90) were conducted in sub-Saharan Africa, primarily in East Africa (55) and Southern Africa (24). The most common forms of integration were (i) HIV testing and counselling added to non-HIV services and (ii) non-HIV services added to antiretroviral therapy (ART). The most commonly integrated non-HIV services were maternal and child healthcare, tuberculosis testing and treatment, primary healthcare, family planning, and sexual and reproductive health services. Values for HIV care cascade outcomes tended to be better in integrated services: uptake of HIV testing and counselling (pooled risk ratio [RR] across 37 studies: 1.67 [95% CI 1.41-1.99], p < 0.001), ART initiation coverage (pooled RR across 19 studies: 1.42 [95% CI 1.16-1.75], p = 0.002), time until ART initiation (pooled RR across 5 studies: 0.45 [95% CI 0.20-1.00], p = 0.050), retention in HIV care (pooled RR across 19 studies: 1.68 [95% CI 1.05-2.69], p = 0.031), and viral suppression (pooled RR across 9 studies: 1.19 [95% CI 1.03-1.37], p = 0.025). Also, treatment success for non-HIV-related diseases and conditions and the uptake of non-HIV services were commonly higher in integrated services. We did not find any significant differences for the following outcomes in our meta-analyses: HIV testing yield, ART adherence, HIV-free survival among infants, and HIV and non-HIV mortality. We could not conduct meta-analyses for several outcomes (HIV infections averted, costs, and cost-effectiveness), because our systematic review did not identify sufficient poolable studies. Study limitations included possible publication bias of studies with significant or favourable findings and comparatively weak evidence from some world regions and on integration of services for key populations in the HIV response.

CONCLUSIONS

Integration of HIV services and other health services tends to improve health and health systems outcomes. Despite some scientific limitations, the global evidence shows that service integration can be a valuable strategy to boost the sustainability of the HIV response and contribute to the goal of 'ending AIDS by 2030', while simultaneously supporting progress towards universal health coverage.

Effectiveness of targeting fathers for breastfeeding promotion: systematic review and meta-analysis

BACKGROUND

Further research gaps exist in relation to the promotion of breastfeeding. Robust scientific evidence obtained by a meta-analysis would provide objectively summarized data while enabling the assessment of consistency of findings. This review includes the first documented meta-analysis done on the effectiveness of targeting fathers for promoting breastfeeding (BF). Assessments have been done for a primary outcome and for six more secondary outcomes.

METHODS

PubMed, EMBASE, Google Scholar, CENTRAL databases and unpublished researches were searched. Selections of randomized-controlled trials and quasi-experimental studies were done in three rounds. Heterogeneity and potential publication bias were assessed. Eight studies were included in meta-analysis and others in narrative synthesis of the outcomes. Pooling was done with the Mental- Haenszel method using risk ratio (RR). Summary-of-Findings table was composed by Review-Manager (version 5.3) and GRADEproGDT applications. Subsequent sensitivity analysis was done.

RESULTS

Selected eight interventional studies included 1852 families. Exclusive BF at six months was significantly higher (RR = 2.04, CI = 1.58-2.65) in the intervention groups. The RR at 4 months was 1.52 (CI = 1.14 to 2.03). Risk of full-formula-feeding (RR = 0.69, CI = 0.52-0.93) and the occurrence of lactation-related problems were lower in the intervention groups (RR = 0.24, CI = 0.10-0.57). More likelihood of rendering support in BF-related issues was seen in intervention groups (RR = 1.43, CI = 1.22-1.68). Increase of maternal knowledge and favorable attitudes on BF were higher in the intervention groups (P ≤; 0.001). The quality of evidence according to GRADE was "low" (for one outcome), "moderate" (for four outcomes), and "high" (for two outcomes).

CONCLUSIONS

Targeting fathers in promotion of BF has provided favorable results for all seven outcomes with satisfactory quality of evidence. This review was registered in the PROSPERO-registry (ID: 2017-CRD42017076163) prior to its commencement.

Yoga and Quality of Life in Women with Primary Dysmenorrhea: A Systematic Review

INTRODUCTION

Primary dysmenorrhea is a prevalent condition causing quality of life (QOL) reduction for many women, resulting from pain as well as parallel social and psychological distress. Yoga reduces pain and sympathetic reactivity, thus promoting QOL. This article reports a systematic review of the evidence for the effectiveness of yoga as a QOL improvement method for women with primary dysmenorrhea.

METHODS

The PRISMA guidelines were used in preparation of this review. Ovid MEDLINE, PsycINFO, CINAHL, Scopus, PubMed, ScienceDirect, Cochrane Database of Systematic Reviews (CDSR), and Cochrane Central Register of Controlled Trials (CENTRAL) were screened through January 2017 using the keywords yoga, meditation, menstrual cycle, dysmenorrhea, pelvic pain, and prostaglandins. English-language randomized controlled trials (RCTs) and quasi-experimental studies regarding yoga, primary dysmenorrhea, and QOL were eligible; all yoga styles were included. Two independent reviewers rated the methodological quality of each study selected for review using the Downs and Black checklist; possible scores ranged from 0 to 32. Ratings were established through consensus.

RESULTS

The search yielded a total of 378 articles, of which 14 (age range 13-45 years, N = 1409) met the criteria for final review: 8 RCTs and 6 quasi-experimental studies. Downs and Black ratings were predominantly moderate in quality with moderate risk of bias, ranging from 15 to 23 (RCTs) and 10 to 17 (quasi-experimental studies). Statistically significant improvements along most QOL domains, including physical pain, sleep, concentration, negative feelings, social relationships, work capacity, and overall QOL, were identified after a yoga intervention. Results indicate preliminary evidence for yoga as a safe and effective QOL improvement method for women with primary dysmenorrhea.

DISCUSSION

Practitioners may consider yoga for management of primary dysmenorrhea. However, future research using larger RCTs of high methodological quality is needed to ascertain the magnitude of yoga's clinical significance.

Quasi-experimental study designs series-paper 1: introduction: two historical lineages

OBJECTIVES

The objective of this study was to contrast the historical development of experiments and quasi-experiments and provide the motivation for a journal series on quasi-experimental designs in health research.

STUDY DESIGN AND SETTING

A short historical narrative, with concrete examples, and arguments based on an understanding of the practice of health research and evidence synthesis.

RESULTS

Health research has played a key role in developing today's gold standard for causal inference-the randomized controlled multiply blinded trial. Historically, allocation approaches developed from convenience and purposive allocation to alternate and, finally, to random allocation. This development was motivated both by concerns for manipulation in allocation as well as statistical and theoretical developments demonstrating the power of randomization in creating counterfactuals for causal inference. In contrast to the sequential development of experiments, quasi-experiments originated at very different points in time, from very different scientific perspectives, and with frequent and long interruptions in their methodological development. Health researchers have only recently started to recognize the value of quasi-experiments for generating novel insights on causal relationships.

CONCLUSION

While quasi-experiments are unlikely to replace experiments in generating the efficacy and safety evidence required for clinical guidelines and regulatory approval of medical technologies, quasi-experiments can play an important role in establishing the effectiveness of health care practice, programs, and policies. The papers in this series describe and discuss a range of important issues in utilizing quasi-experimental designs for primary research and quasi-experimental results for evidence synthesis.

Quasi-experimental study designs series-paper 5: a checklist for classifying studies evaluating the effects on health interventions-a taxonomy without labels

Objectives

The aim of the study was to extend a previously published checklist of study design features to include study designs often used by health systems researchers and economists. Our intention is to help review authors in any field to set eligibility criteria for studies to include in a systematic review that relate directly to the intrinsic strength of the studies in inferring causality. We also seek to clarify key equivalences and differences in terminology used by different research communities.

Study Design and Setting

Expert consensus meeting.

Results

The checklist comprises seven questions, each with a list of response items, addressing: clustering of an intervention as an aspect of allocation or due to the intrinsic nature of the delivery of the intervention; for whom, and when, outcome data are available; how the intervention effect was estimated; the principle underlying control for confounding; how groups were formed; the features of a study carried out after it was designed; and the variables measured before intervention.

Conclusion

The checklist clarifies the basis of credible quasi-experimental studies, reconciling different terminology used in different fields of investigation and facilitating communications across research communities. By applying the checklist, review authors' attention is also directed to the assumptions underpinning the methods for inferring causality.