Western Journal of Nursing Research | 2021
Measurement Issues in Foot Health Research: Time to Step Up
Abstract
As the population ages and the number of persons with chronic health conditions continues to increase, researchers must focus on developing and testing strategies to keep older adults healthy and facilitate aging in place. Foot problems are of particular interest in the older adult population as they can lead to falls as well as decreased mobility, loss of independence, and lower quality of life. Nurses are uniquely positioned to implement community-based interventions to decrease foot problems. In order to determine intervention efficacy, researchers need reliable, reproducible, and valid tools that are sensitive to change and measure foot health outcomes that can be impacted by foot care self-management such as blisters, corns, calluses, dry and cracking skin, and long or ingrown toenails. To maximize its utility, the tool needs to be appropriate for usage in a variety of patient populations. The majority of foot health–specific tools found in the literature measure foot and ankle outcomes after orthopedic and/or podiatric surgery. The American Orthopedic Foot and Ankle Score (AOFAS), which subjectively and objectively measures alignment, function, and pain of the anklehindfoot, midfoot, hallux, and lessor toes, is the most frequently used tool found in the literature (Shazadeh Savafi et al., 2018). Reported limitations of the AOFAS tool include combining ordinal and interval-level data; combining provider and patient responses; limited evaluation of the tool’s validity, reliability, and responsiveness; and difficulties with interpreting the results (Shazadeh Savafi et al., 2018). Moreover, while the AOFAS tool provides outcomes of interest to foot and ankle surgeons, the only item reflective of foot care self-management is callus assessment. Another common category of foot health–specific tools is clinical assessment scales, used to evaluate the diabetic patient population for diabetic foot disease outcomes. Clinical assessment scales have been developed to assess diabetic nephropathy, ulceration risk, ulcer healing, ulcer infection, and amputation risk (Fernández-Torres et al., 2020). Many of these clinical assessment scales were created for the purposes of clinical documentation rather than research and have undergone limited psychometric evaluation. For example, several diabetic foot screening tools have been developed to identify individuals at high risk for diabetic foot ulceration. Although some diabetic foot screening tools have inter-rater reliability and/or predictive validity (Fernández-Torres et al., 2020) and include select items relevant to foot care self-management (e.g., calluses and fissures), their utility for evaluating the efficacy of foot selfcare management is limited. Diabetic foot screening tools have been developed and tested for use in patients with diabetes; they have not been validated in older adult populations without diabetes; and their scores strive to quantify the risk and need for foot care referral rather than providing a quantitative, summative outcome score that can be used to monitor the effects of foot care self-management over time. Few tools are available in the published literature to measure aspects of foot health, which can be improved through foot care self-management practices. Persaud et al. (2018) recently developed and validated the Healthy Foot Screen, a clinical tool designed for primary care providers to identify common foot problems in the general population. Similar to diabetic foot screening tools, however, the Healthy Foot Screen tool lacks the ability to effectively measure foot health changes over time. Specifically, the Healthy Foot Screen addresses a limited number of skin and nail problems (i.e., fungal infection, trauma, and skin dryness); it includes items that cannot be affected by selfmanagement practices (e.g., bony deformities), and the items only assess presence or absence of foot problems rather than providing a quantitative outcome. In contrast, the Foot Health Score holds promise as a tool to quantitatively measure foot health outcomes in the general population over time. The Foot Health Score provides an objective health care provider assessment of not only the presence but also the severity of 15 common podiatric conditions and scores each condition on a numeric scale of absent, mild, moderate, or severe (Baba et al., 2015). Importantly, the items assessed by the Foot Health Score can be impacted by foot care self-management interventions. While the Foot Health Score and the Revised Foot Health Score have been used in studies to measure foot health outcomes (Baba et al., 2015; O’Connor et al., 2020; O’Connor & Wipke-Tevis, 2020), additional research is needed to establish the psychometric properties of these tools. Given the rising numbers of older adults, researchers must develop and test interventions to improve foot health to help preserve older adults’ mobility and independence. In order to measure the efficacy of these interventions, we need psychometrically sound foot health tools. It is time for foot 997472WJNXXX10.1177/0193945921997472Western Journal of Nursing ResearchO’Connor and Wipke-Tevis editorial2021