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Background:

Rehabilitation providers and policymakers need valid evidence to make informed decisions about the healthcare needs of populations. Whenever possible, these decisions should be informed by randomized controlled trials (RCTs). However, there are circumstances when evidence needs to be generated rapidly, or when RCTs are not ethical or feasible. These situations apply to studying the effects of complex interventions, including rehabilitation. Therefore, it is necessary to consider how alternative designs to RCTs can provide valid estimates of the cause-and-effect relationship between rehabilitation interventions and functioning.

Objectives:

We aim to explore the target trial emulation framework by Hernán and colleagues to obtain valid estimates of the causal effects of rehabilitation when RCTs cannot be conducted. We outline the methodology of designing cohort and quasi-experimental studies based on target trial emulation, including protocol development and observational data necessary to make causal inferences.

Methods:

Target trial emulation guides the design and analysis of non-randomized comparative effectiveness studies using observational data, by emulating a hypothetical RCT. Cochrane Rehabilitation defines rehabilitation as a multimodal, person-centered, and collaborative process targeting a person's capacity or contextual factors related to performance to optimize functioning. In the context of rehabilitation, we outline steps of target trial emulation: 1) Articulating the causal question and protocol; 2) Emulating the components of a protocol representing the target trial (Figure-1). We discuss counterfactual theory as foundational to estimating causal effects, methodological considerations (e.g., advanced analytic methods to achieve comparability at baseline), limitations and mitigating strategies (e.g., quantitative bias analyses to examine potential impact of unmeasured confounding).

Conclusions:

This methodological paper describes target trial emulation by Hernán and colleagues applied to rehabilitation. This approach is important to obtain valid estimates of the causal effects of rehabilitation when evidence needs to be generated rapidly or RCTs are not ethical or feasible. Despite some limitations, target trial emulation is a methodologically robust option to RCTs, and this approach informs future work in systematic reviews and risk-of-bias assessments concerning treatment effectiveness of rehabilitation. Relevance for patients: We are strengthening methodological approaches to estimating causal effects of rehabilitation when RCTs cannot be conducted for more robust evidence production."