Higher rates of all-cause mortality and resource utilization during episodes-of-care for diabetic foot ulceration.

AIMS: Our primary objective was to determine whether all-cause rates of mortality and resource utilization were higher during periods of diabetic foot ulceration. In support of this objective, a secondary objective was to develop and validate an episode-of-care model for diabetic foot ulceration. METHODS: We evaluated data from the Medicare Limited Data Set between 2013 and 2019. We defined episodes-of-care by clustering diabetic foot ulcer related claims such that the longest time interval between consecutive claims in any cluster did not exceed a duration which was adjusted to match two aspects of foot ulcer episodes that are well-established in the literature: healing rate at 12 weeks, and reulceration rate following healing. We compared rates of outcomes during periods of ulceration to rates immediately following healing to estimate incidence ratios. RESULTS: The episode-of-care model had a minimum mean relative error of 4.2% in the two validation criteria using a clustering duration of seven weeks. Compared to periods after healing, all-cause inpatient admissions were 2.8 times more likely during foot ulcer episodes and death was 1.5 times more likely. CONCLUSIONS: A newly-validated episode-of-care model for diabetic foot ulcers suggests an underappreciated association between foot ulcer episodes and all-cause resource utilization and mortality.

Lower extremity reamputation in people with diabetes: a systematic review and meta-analysis.

In this study, we determined the reamputation-free survival to both limbs and to the contralateral limb only following an index amputation of any-level and assessed whether reamputation rates have changed over time. We completed a systematic search using PubMed and screened a total of 205 articles for data on reamputation rates. We reported qualitative characteristics of 56 studies that included data on reamputation rates and completed a meta-analysis on 22 of the studies which enrolled exclusively participants with diabetes. The random-effects meta-analysis fit a parametric survival distribution to the data for reamputations to both limbs and to the contralateral limb only. We assessed whether there was a temporal trend in the reamputation rate using the Mann-Kendall test. Incidence rates were high for reamputation to both limbs and to the contralateral limb only. At 1 year, the reamputation rate for all contralateral and ipsilateral reamputations was found to be 19% (IQR=5.1%-31.6%), and at 5 years, it was found to be 37.1% (IQR=27.0%-47.2%). The contralateral reamputation rate at 5 years was found to be 20.5% (IQR=13.3%-27.2%). We found no evidence of a trend in the reamputation rates over more than two decades of literature analyzed. The incidence of lower extremity reamputation is high among patients with diabetes who have undergone initial amputations secondary to diabetes, and rates of reamputation have not changed over at least two decades.

Recurrence rates suggest delayed identification of plantar ulceration for patients in diabetic foot remission.

INTRODUCTION: Foot ulcers are a common and costly complication of diabetes, and delays in treatment can result in impaired healing, infection, hospitalization, and lower extremity amputation. RESEARCH DESIGN AND METHODS: We aimed to determine whether patterns in plantar diabetic foot ulcer (DFU) recurrence coincided with typical intervals between routine preventive care appointments, which would suggest that delays exist between ulcer development and identification. We completed an analysis of existing data from two multicenter studies in 300 total participants. We analyzed unadjusted counts of DFU binned in weekly intervals and defined 'exam periods' as intervals from 2 to 4 weeks, from 6 to 8 weeks, within 1 week of 3 months and within 1 week of 6 months. We tested whether recurrence rates during exam periods were equivalent to rates outside exam periods. We estimated the delay between DFU development and DFU identification such that the rate of development would have been constant. RESULTS: During exam periods, a total of 43 DFUs were identified (43/86=50%) despite the fact that these periods represent only 23.5% of follow-up in aggregate. Accounting for censoring, the annualized incidence during exam periods was 0.68 DFU/year (CI 0.48 to 0.89) in contrast to 0.25 DFU/year (CI 0.18 to 0.32) outside exam periods (incidence ratio=2.8, CI 1.8 to 4.3). We estimated delays between DFU occurrence and identification to average 15.3 days (IQR 7.4-23.7 days). CONCLUSIONS: These findings have potential implications for practice, particularly related to the value of telehealth and in-home monitoring of patients in diabetic foot remission. Additionally, there are implications for study design, which should consider the impact of interval censoring and attempt to control for confounders related to frequency and timing of exams.

Lower resource utilization for patients with healed diabetic foot ulcers during participation in a prevention program with foot temperature monitoring.

INTRODUCTION: We assessed the impact of a diabetic foot ulcer prevention program incorporating once-daily foot temperature monitoring on hospitalizations, emergency department and outpatient visits, and rates of diabetic foot ulcer recurrence and lower extremity amputations for patients with recently healed foot ulcers. RESEARCH DESIGN AND METHODS: In this retrospective analysis of real-world data, we enrolled 80 participants with a healed diabetic foot ulcer in a year-long foot ulcer recurrence prevention program. Four outpatient centers within a large integrated healthcare system in the USA contributed to enrollment. We evaluated diabetic foot-related outcomes and associated resource utilization for participants during three periods: the 2 years before the program, the year during the program, and after the program ended. We reported unadjusted resource utilization rates during the program and the periods before and after it. We then adjusted rates of outcomes in each phase using an interrupted time series approach, explicitly controlling for overall trends in resource utilization and recurrence during the three periods. RESULTS: Our unadjusted data showed high initial rates of resource utilization and recurrence before enrollment in the program, followed by lower rates during the program, and higher rates of resource utilization and similar rates of recurrence in the period following the end of the program. The adjusted data showed lower rates of hospitalizations (relative risk reduction (RRR)=0.52; number needed to treat (NNT)=3.4), lower extremity amputations (RRR=0.71; NNT=6.4), and outpatient visits (RRR=0.26; absolute risk reduction (ARR)=3.5) during the program. We also found lower rates of foot ulcer recurrence during the program in the adjusted data, particularly for wounds with infection or greater than superficial depth (RRR=0.91; NNT=4.4). CONCLUSIONS: We observed lower rates of healthcare resource utilization for high-risk participants during enrollment in a diabetic foot prevention program incorporating once-daily foot temperature monitoring. TRIAL REGISTRATION NUMBER: NCT04345016.

Use of a Remote Temperature Monitoring Mat for the Early Identification of Foot Ulcers.

INTRODUCTION: Diabetic foot ulcers (DFUs) are responsible for considerable morbidity, mortality, and cost. Remote temperature monitoring (RTM) is an evidenced-based and recommended component of standard foot care for at-risk patients. Although previous research has demonstrated the value of RTM for foot ulcer prevention, its benefits related to the early identification of diabetic foot complications may be underappreciated. OBJECTIVE: This article presents a case series supporting the use of RTM for early identification of DFUs. MATERIALS AND METHODS: The cases of 4 veteran patients who presented consecutively with inflammation, which was detected by a telemedicine temperature monitoring mat, are reported. The authors collected subjective history from each patient via telephone outreach and triaged these patients according to standard diabetic foot care recommendations. RESULTS: Each patient required a clinical exam prompted by the mat and the patient's subjective history. In each case, the patient required callus debridement upon which a pre-ulcerative lesion or partial-thickness wound was discovered. The DFUs in these 4 cases healed quickly and without complication. In 2 of the cases, the outreach prompted by the mat reestablished specialist foot care after a prolonged period without routine exam. CONCLUSIONS: In each of these cases, the RTM mat detected inflammation accompanying a preulcerative lesion or a partial-thickness wound, allowing for timely intervention and treatment, including debridement and offloading, which may have the potential to improve care and reduce morbidity, mortality, and costs.

Accuracy of a foot temperature monitoring mat for predicting diabetic foot ulcers in patients with recent wounds or partial foot amputation.

AIMS: To assess the accuracy of once-daily foot temperature monitoring for predicting foot ulceration in diabetic patients with recent wounds and partial foot amputation, complications previously perceived as challenging. METHODS: We completed a planned analysis of existing data from a recent study in 129 participants with a previously-healed diabetic foot ulcer. We considered four cohorts: all participants, participants with partial foot amputation, participants with a recent wound, and participants without partial foot amputation and without a recent wound. We reported the prediction specificity, lead time, and annualized alert frequency in each cohort at maximum sensitivity. We assessed the two potentially challenging cohorts for non-inferior accuracy relative to the control cohort using Delong's method. RESULTS: We report non-inferior predictive accuracy in each of the two potentially-challenging cohorts relative to the control cohort (⍺ < 0.05). The alert lead time was similar across these cohorts, ranging from 33 to 42 days. CONCLUSIONS: Once-daily foot temperature monitoring is no less accurate for predicting foot ulceration in those with recent wounds and partial foot amputations than in those without these complications. These results support expanded practice of once-daily foot temperature monitoring, which may result in improved patient outcomes and reduced healthcare resource utilization.

Ulcer metastasis? Anatomical locations of recurrence for patients in diabetic foot remission.

BACKGROUND: The "cancer analogy" is powerful for communicating risk to and organizing care for patients with diabetic foot syndrome. One potentially underappreciated similarity between cancer and foot ulcers is that both can recur at anatomical locations distinct from the primary occurrence, albeit with different physiological mechanisms. Few studies have characterized the location of diabetic foot ulcer recurrence, and these have been limited by considering only the first recurrent wound following a recent-healed wound. We therefore characterized the anatomical locations at which diabetic foot ulcers are likely to recur considering multiple wounds during follow-up and the locations of all prior wounds documented in the participant's history. METHODS: We completed a secondary analysis of existing data from a 129 participant multi-center study of participants in diabetic foot remission. The primary outcome was plantar foot ulceration, and each participant was followed for 34 weeks or until withdrawing consent, allowing characterization of all wounds occurring. We stratified the anatomical locations of wounds prior to the trial by the following outcome categories during the trial: no recurrence, recurrence to the same anatomical location, recurrence to a different anatomical location on the same foot, and recurrence to the contralateral foot. RESULTS: A large percentage (48%) of wounds recurred to the contralateral foot, and the proportion of subsequent foot ulcer to the contralateral limb was largely unaffected by the anatomical location of foot ulcer prior to the study. Only 17% of prior diabetic foot ulcers were followed by recurrence to the same anatomical location. Rates of recurrence remained high during treatment of a wound (0.41 foot ulcer/ulcer-year). Participants had documented wounds to 2.2 distinct anatomical locations on average, and more than 60% of participants had wounds to more than one plantar location by the end of the study. CONCLUSIONS: Given the significant morbidity, mortality, and resource utilization associated with foot ulcer recidivism, quality and evidenced-based preventive care is essential. Our results better characterize the burden of recurrence and to what anatomy recurrence is most likely. These insights may benefit providers and patients alike for the provision of high-quality preventive care thereby resulting in reduced morbidity, mortality, and cost. TRIAL REGISTRATION: The study providing the data for this secondary analysis was registered on ClinicalTrials.gov (NCT02647346) on January 6, 2016. The study was retrospectively registered.

Unilateral remote temperature monitoring to predict future ulceration for the diabetic foot in remission.

Objective: Daily remote foot temperature monitoring is an evidence-based preventive practice for patients at risk for diabetic foot complications. Unfortunately, the conventional approach requires comparison of temperatures between contralaterally matched anatomy, limiting practice in high-risk cohorts such as patients with a wound to one foot and those with proximal lower extremity amputation (LEA). We developed and assessed a novel approach for monitoring of a single foot for the prevention and early detection of diabetic foot complications. The purpose of this study was to assess the sensitivity, specificity, and lead time associated with unilateral diabetic foot temperature monitoring. Research design and methods: We used comparisons among ipsilateral foot temperatures and between foot temperatures and ambient temperature as a marker of inflammation. We analyzed data collected from a 129-participant longitudinal study to evaluate the predictive accuracy of our approach. To evaluate classification accuracy, we constructed a receiver operator characteristic curve and reported sensitivity, specificity, and lead time for four different monitoring settings. Results: Using this approach, monitoring a single foot was found to predict 91% of impending non-acute plantar foot ulcers on average 41 days before clinical presentation with a resultant mean 4.2 alerts per participant-year. By adjusting the threshold temperature setting, the specificity could be increased to 78% with corresponding reduced sensitivity of 53%, lead time of 33 days, and 2.2 alerts per participant-year. Conclusions: Given the high incidence of subsequent diabetic foot complications to the sound foot in patients with a history of proximal LEA and patients being treated for a wound, practice of daily temperature monitoring of a single foot has the potential to significantly improve outcomes and reduce resource utilization in this challenging high-risk population.

Feasibility and Efficacy of a Smart Mat Technology to Predict Development of Diabetic Plantar Ulcers.

OBJECTIVE: We conducted a multicenter evaluation of a novel remote foot-temperature monitoring system to characterize its accuracy for predicting impending diabetic foot ulcers (DFU) in a cohort of patients with diabetes with previously healed DFU. RESEARCH DESIGN AND METHODS: We enrolled 132 participants with diabetes and prior DFU in this 34-week cohort study to evaluate a remote foot-temperature monitoring system (ClinicalTrials.gov Identifier NCT02647346). The study device was a wireless daily-use thermometric foot mat to assess plantar temperature asymmetries. The primary outcome of interest was development of nonacute plantar DFU, and the primary efficacy analysis was the accuracy of the study device for predicting the occurrence of DFU over several temperature asymmetry thresholds. RESULTS: Of the 129 participants who contributed evaluable data to the study, a total of 37 (28.7%) presented with 53 DFU (0.62 DFU/participant/year). At an asymmetry of 2.22°C, the standard threshold used in previous studies, the system correctly identified 97% of observed DFU, with an average lead time of 37 days and a false-positive rate of 57%. Increasing the temperature threshold to 3.20°C decreased sensitivity to 70% but similarly reduced the false-positive rate to 32% with approximately the same lead time of 35 days. Approximately 86% of the cohort used the system at least 3 days a week on average over the study. CONCLUSIONS: Given the encouraging study results and the significant burden of DFU, use of this mat may result in significant reductions in morbidity, mortality, and resource utilization.