Methodology. The clinical question for this systematic review was generated using the Population Intervention Comparison Outcome18 (PICO) model for clinical questioning. The question was: In adult patients with chronic diabetes-related foot ulcers, what effect does LFUD have on ulcer healing rates compared to NSSD?
This question was separated into terms to search electronic databases including Ovid, MEDLINE, EMBASE, the Cumulative Index of Nursing and Allied Health Literature Plus, and the Cochrane Database of Systematic Reviews from the earliest date publications were available in each index until April 2017. Table 1 shows the search terms used. Searches were restricted to human studies and English-language articles.
Two (2) authors independently reviewed the title and abstract of all retrieved studies against the eligibility criteria (see Table 2), which specified chronic diabetes-related foot ulcers (>4 weeks’ duration) in adults >18 years of age. Publications were excluded if 1) the methods of debridement did not involve comparing LFUD to NSSD, 2) wounds demonstrated an etiology other than a diabetes-related foot ulceration, or 3) the study involved acute ulcers, ulcers that did not undergo debridement, and diagnostic or dental ultrasound.
When the 2 authors disagreed regarding study inclusion, a third author helped resolve the issue through discussion. The full text of articles was obtained when the abstract seemed uncertain. Forward and backward searching strategies also utilized the reference lists and Google Scholar citations of articles included within the full text review.
Data extraction. General demographics such as gender, country, age, diabetes type, and method of wound debridement of each participant group were extracted from each included study and tabulated and summarized in Table 3. The primary outcome of interest was healing rates of diabetes-related foot ulcers. The secondary outcome of interest was the percentage of ulcers healed.
All articles included within the review underwent methodological assessment for risk of bias using the quality indicators as outlined by Physiotherapy Evidence Database (PEDro).19 This scale has 11 indicators to identify any risk of bias. Each indicator was given a score of - if not included, ? if not mentioned, or + if included. According to the PEDro guidelines, criteria 2 to 11 are used for scoring purposes, so a score out of 10 is calculated.
Two (2) authors completed this assessment independently and resolved any disagreements. Articles also were classified into levels of evidence using criteria set out by the Oxford Centre for Evidence-based Medicine.20 This provides advice on the most appropriate research to guide treatment. Systematic reviews of randomized controlled trials are the highest level of evidence (Level 1), followed by randomized controlled trials (Level 2), nonrandomized controlled cohort/follow-up studies (Level 3), cohort studies and/or case studies (Level 4), and mechanism-based reasoning (Level 5).
Data collection. Primary outcome of percentage of ulcers healed were extracted into an Excel worksheet (Microsoft Excel, version 16.15, Redmond, WA).
Data analysis. Analysis was performed using Stata 13 software (College Station, TX). Random effect meta-analysis was performed where data were available for similar outcomes evaluated in more than 1 study. Authors were contacted to request additional data for studies not reporting sufficient outcome data for inclusion in the meta-analysis; however, no responses were received, thus eliminating 2 of the 4 studies from analysis.