Researchers have found that the AMPREDICT decision support tool (DST) demonstrates “strong usability characteristics and clinical relevance” in amputation level decision-making for patients with chronic limb-threatening ischaemia (CLTI). Daniel C Norvell (VA Puget Sound Health Care System, Seattle, USA) and colleagues suggest in an online European Journal of Vascular and Endovascular Surgery (EJVES) article that, following “extensive iterative development and testing,” the tool should now be applied in clinical practice.
The authors describe the AMPREDICT DST as “a novel, web-based, clinical DST that calculates individual one-year postoperative risk of death, reamputation, and probability of achieving independent mobility by amputation level”.
They detail that there are currently a lack of individual patient risk factors informing available evidence on amputation level decision-making in patients with CLTI, which instead relies on average population risks. As a result, there is “significant variation of amputation levels across health systems, geographical regions, and time,” the authors state.
While prediction models have been published to hone in on individual patient risk factors, translation to clinical application “has not been undertaken,” Norvell et al write—a gap in the literature this study sought to address. Specifically, the investigators aimed to translate the previously validated AMPREDICT prediction models by “developing and testing the usability of the AMPREDICT DST”.
The investigators explain that a mixed-methods approach was applied to assess the AMPREDICT DST. “Previously validated prediction models were translated into a web-based DST with additional content and format developed by an expert panel,” they explain.
Elaborating on their methods, Norvell and colleagues note that ten clinician end users “from diverse specialities, sex, geography, and clinical experience” assessed tool usability while interacting with the tool using a hypothetical case scenario and an example from their practice. The clinicians engaged in a “think aloud” approach so that investigators could go back and review the interactions. After the interaction, each clinician participated in a semi-structured qualitative interview to evaluate the AMPREDICT DST’s look and feel, user friendliness, readability, functionality, and potential implementation changes. In addition, they completed the Post-Study System Usability Questionnaire (PSSUQ)—a 16-item scale with scores ranging from 1–7, with lower scores indicating greater usability.
Writing in EJVES, the authors report that “most providers said they were eager to use the AMPREDICT DST and some requested to use it as soon as possible”. Furthermore, the qualitative interviews suggested the potential utility of the DST included the following: assistance in counselling patients on amputation level decisions, setting outcome expectations, and use as a tool in the academic environment to facilitate understanding of factors that contribute to various outcome risks. The authors also communicate “favourable” overall and subscale PSSUQ scores, with a mean overall total score of 1.57 (standard deviation [SD], 0.69) and a range from 1–3.21.
Norvell et al acknowledge that the AMPREDICT DST has limitations. For example, they recognise that “the risks produced by the tool are generated from models developed in patients undergoing their first major amputation who did not have severe comorbidities (e.g. coma, paraplegia, quadriplegia, disseminated cancer, tumour of the central nervous system, ventilator dependent) that would put them at high risk of death and more likely a candidate for transfemoral amputation only.
Another issue raised is that the models were developed and validated in a US Veteran population with CLTI, comprising mainly males. Therefore, the use of the DST in other populations “should be considered with caution, since the management and risks of patients in VHA [Veteran Health Administration] hospitals may differ from other populations”.
Despite these drawbacks, the authors stress that the tool is set to move into the next phase of development and evaluation with integration into the VHA electronic health record (EHR). This, they state, will allow for assessment of its impact on physician and patient shared amputation level decision-making.
