TempTouch IR Thermometry & Diabetic Patient Self-Care
Condition: Diabetic Polyneuropathy; Diabetic Foot Ulcer; Diabetes; Foot Infection
MeSH terms: Polyneuropathies; Diabetic Neuropathies; Diabetic Foot; Foot Ulcer
Study type: Interventional
Phase: Phase 2/Phase 3

Summary: 
      Foot ulcers develop in diabetics with neuropathy because of cumulative injury over the course
      of several days. These patients do not feel pain, and do not recognize their foot is being
      injured until a wound develops. Areas about to ulcerate become inflamed and "hot spots" can
      be identified. This study's purpose is to evaluate the effectiveness of a home infrared
      temperature probe designed to forewarn patients that an area on the foot is inflamed so they
      can take preventive measures. The study will evaluate the incidence of diabetic foot ulcers
      among high-risk patients, evaluate the cost of home temperature monitoring compared to
      standard therapy, and evaluate patient satisfaction. 180 diabetics at high-risk of having
      foot complications will be randomized into 3 treatment arms: 1) standard therapy consisting
      of regular foot care; 2) standard therapy plus recording of a structured foot evaluation
      using a hand mirror; and 3) standard therapy plus infrared home temperature assessment to
      identify "hot spots." Device patients will measure temperatures at 6 sites on the foot each
      day. When temperatures are elevated >4°F patients will contact the research nurse and
      decrease activity. The primary study outcome will be incident foot ulcers and Charcot
      fractures.
    

Detailed description: 
      SIGNIFICANCE & RATIONALE FOR PROPOSED PROJECT Foot problems are the most common complication
      in diabetics leading to hospitalization.1-5 Approximately one quarter of all hospital days
      for persons with diabetes are related to foot complications.4,5,8 In the United States there
      are approximately 120,000 non-traumatic lower extremity amputations performed each year.6,7
      In the U.S., 45%-83% of all lower extremity amputations involve diabetics.1,9,5 Overall,
      patients with diabetes are 15-46 times more likely to have an amputation than patients
      without diabetes.11,14,15 It has been estimated that 5% to 15% of diabetics will have a lower
      extremity amputation in their lifetime.11 After their initial amputation 9-17% of diabetic
      patients will experience a second amputation within the same year12-17 and 25% to 68% of
      diabetics will have an amputation of the contralateral extremity within five years.18-20 The
      five-year survival rate after a lower extremity amputation ranges from 41% to 70%.19-21
      Indeed, 10% of these patients die before leaving the hospital after a lower extremity
      amputation.7,9,20 National Initiatives: There are a number of initiatives by federal and
      state government organizations to prioritize efforts to reduce the burden of diabetes related
      amputations. Healthy People 2000 and Healthy People 2010 have set a goal of reducing the
      incidence of diabetes related amputation by 40%, and the U.S. Department of Health and Human
      Services has prioritized amputation reduction in minorities as one of its strategic
      Initiatives to Eliminate Racial and Ethnic Disparities in Health. Likewise, the Veterans
      Administration and Indian Health Service have prioritized amputation prevention for patients
      with diabetes. For instance, the VA has mandated the development of special programs to
      evaluate patients with diabetes, identify patients that fit a high-risk profile, and provide
      specialized treatment programs in order to decrease the impact of diabetes related
      complications within the Veterans Health Administration. Lower extremity complications in
      diabetics are common, costly and associated with a high rate of recurrence, morbidity and
      mortality. Several studies in the U.S. and Europe suggest that amputations and ulcerations
      can be prevented when special foot care and education are implemented. Despite these types of
      initiatives, increasing research knowledge, better re-vascularization and diagnostic
      procedures and an expanding armamentarium of new drugs and technology, the incidence of
      amputation has increased over the past few decades.15 Precursors to amputation: In diabetes,
      as in other chronic diseases, patient involvement to identify early warning signs of the
      disease process is imperative to reduce the incidence of complications and prevent morbidity.
      Many lower extremity complications involve sensory neuropathy as a pivotal component of the
      critical pathway for both the development of ulcers and amputations. Therefore, pain and loss
      of function, primary natural warning systems that alert us to take action and seek medical
      care, are faulty. Diabetic patients can hence sustain injuries that are not recognized until
      they are so severe that full thickness ulcerations result. The aim of this study was to
      further evaluate a tool to help high-risk diabetics identify areas on their feet that are
      inflamed and prone to ulceration before a wound develops at sites that would otherwise not be
      recognized as "symptomatic." Results of the Phase I study indicated that high-risk patients
      with diabetes can effectively use an infrared temperature device to monitor foot
      temperatures. Patients who used the device had significantly fewer foot complications
      compared to patients who received education, therapeutic shoes plus insoles and regular foot
      evaluations alone.

      Foot ulcers are one of the most common precursors to diabetes related amputations.8,25 Other
      factors that have been associated with amputation, such as infection, faulty wound healing,
      and ischemia, usually do not cause tissue loss or amputation in the absence of a wound.
      Therefore, ulcer prevention is one of the foci of any amputation prevention program. Three
      primary pathways or mechanisms of injury have recently been identified in the development of
      foot ulcers They include wounds that result from ill-fitting shoes (low-pressure injuries
      that are associated with prolonged or constant pressure from narrow or short shoes),
      repetitive moderate forces on the sole of the foot, and from puncture wounds (high-pressure
      injuries with a single exposure of direct pressure). The most common mechanism involves the
      second scenario (receptive moderate force). Except for puncture wounds, areas that are likely
      to ulcerate have been associated with increased local skin temperatures due to inflammation
      and enzymatic autolysis of tissue. Several reports have suggested that wounds develop due to
      a cumulative effect of unrecognized repetitive injury over the course of several days.
      Identifying areas of injury by the presence of inflammation would then allow patients or
      health care providers to take action to decrease the inflammation before a wound develops.

      Effectiveness of prevention: Several studies have suggested that foot complications can be
      prevented by a focused team approach to identify and treat lower extremity complications.
      This approach generally involves de-weighting pressure areas with special shoes, patient
      education and self-care practices, re-vascularization, optimal glucose control, infection
      control, use of appropriate referral patterns, and regular foot care.18, 26-30 Several
      studies have demonstrated a significant decrease in the incidence of ulceration and
      re-ulceration when therapeutic footwear, education, and regular diabetic foot care was
      provided. However, 19-28% of these patients still re-ulcerated within 12-18 months.26,31,32
      Edmonds and coworkers18 reported a 26% re-ulceration rate in high-risk diabetics with special
      shoes and insoles compared to an 83% re-ulceration rate in patients that wore their own
      shoes. Likewise Uccioli26 reported a 28% re-ulceration rate in diabetics treated with custom
      shoes and insoles compared to 50% re-ulceration among patients without special footwear. In a
      descriptive report, Helm and co-workers32 reported a 19% re-ulceration over an 18-month
      period among patients that healed neuropathic ulcers in total contact casts. As in other
      studies, after wound closure patients received custom shoes or healing sandals and regular
      clinical follow-up care. All of these studies were performed at specialty foot centers with a
      focus on diabetes. Even in these centers, the risk of re-injury was very high.

      Predicting impending injury: Our rationale for evaluating skin temperatures involves the
      search for a quantifiable, reproducible measurement of inflammation that can be used to
      identify pathologic processes before they result in ulcers. Inflammation is one of the
      earliest signs of foot ulceration. Five cardinal signs characterize inflammation: redness,
      pain, swelling, loss of function and heat. Many of these signs are difficult to assess
      objectively. In the neuropathic extremity, pain and disturbance of function may be absent
      because of neuropathy and thus are poor indicators of inflammation. In addition, swelling and
      redness are difficult to objectively grade from clinician to clinician or from visit to
      visit. Most lay people will not be able to understand or accurately evaluate these subtle
      parameters. However, temperature measurements can be easily performed by patients or their
      spouses and provide quantitative information that has been shown to be predictive of
      impending ulceration in diabetics with sensory neuropathy.

      Since ulcers develop as a result of cumulative injury over the course of several days,
      patients need a mechanism to identify early warning signs of ulceration to prompt them to
      take appropriate action.44 The high re-ulceration rates reported in previous studies indicate
      that early warning signs are missed. A home temperature monitoring system for wound
      prevention is a similar concept to home glucose monitoring to help patients adjust their
      insulin. In both cases patients need frequent information about a health parameter that has
      the potential to change in a very short period of time. In both cases patients are taught to
      use the objective data provided from their home monitoring device to alter their behavior
      whether it is used to change insulin dosage or activity level. One of the barriers to
      lowering the incidence of ulcers and amputation is an objective mechanism that patients can
      use at home, such as a home monitoring system.

      In the past, standard patient education focused on teaching patients self-inspection skills
      that most patients could not adequately perform such as using a hand mirror for visual
      inspection. In our study of ulcer risk factors, a large proportion of both patients with and
      without foot ulcers did not have the visual acuity, manual dexterity, or joint flexibility to
      perform simple self-examination checks of their feet. Among ulcer patients 49% could not
      position and/or visualize their feet, and 15% of ulcer patients were legally blind in at
      least one eye. Even if a family member is available to visually inspect the foot, without an
      objective measure of injury, most laymen will only be able to identify ulcers once they have
      occurred.33 State of existing knowledge: Over the last three decades, several authors have
      suggested that skin temperature monitoring may be a valuable tool to detect "at risk" sites
      in patients who are insensate.34-41 As early as 1971 Goller34 reported an association between
      increased local temperature and localized pressure leading to tissue injury. Sandrow and
      coworkers35 subsequently used thermometry as a tool to diagnosis occult neuropathic fractures
      in patients with diabetes in 1972.

      Stess et al.37 and Clark et al.40 described the use of infrared thermography to assess skin
      temperatures in diabetics, diabetics with neuropathic fractures, diabetics with ulcers,
      patients with leprosy, and controls. They found that neuropathic foot ulcers frequently had
      increased skin temperatures surrounding a central necrotic area and suggested that infrared
      thermometry may be a useful technique to identify patients at risk for ulceration.40 Benbow
      and coworkers38 took this work a step further and evaluated foot temperatures as a tool to
      identify diabetics at risk of foot ulceration. They suggested that thermographic patterns
      could be used to screen high-risk patients.38 They prospectively evaluated 50 patients with
      diabetes and sensory neuropathy for 3 to 4 years. Six patients developed a neuropathic ulcer
      during the study period. These patients had significantly higher foot temperatures at
      baseline than patients who did not ulcerate. All of these early studies used liquid crystal
      contact thermography to map temperature patterns on the sole of the foot. The devices used in
      these studies were bulky, expensive and difficult to use or integrate into a normal clinical
      setting.

      In a study at the High-Risk Diabetic Foot Clinic at the University of Texas27 at San Antonio,
      it was hypothesized that local skin temperatures on the affected limb would be higher in
      extremities with pathology (neuropathic ulcers, acute Charcot's arthropathy) and the same in
      patients without pathology when compared to the corresponding site on the contralateral foot.
      Further, it was expected that temperatures return to normal once ulcer and fracture healing
      is complete. Lastly, it was questioned whether dermal thermometry could be potentially
      predictive of neuropathic ulceration. To that end, 143 consecutive patients with diabetes
      that presented for treatment to the High-Risk Diabetic Foot Clinic were enrolled. All were
      evaluated with thermometry. These patients were divided into 3 groups: 78 patients with
      asymptomatic loss of protective threshold, 44 with neuropathic foot ulcerations, and 21
      patients with neuropathic (Charcot) fractures. Temperatures were evaluated with a portable
      handheld infrared skin temperature probe (Dermatemp 1001, Exergen Products, Watertown, MA,
      USA). Patients' skin temperatures were measured at the time pathology was initially
      identified and at subsequent clinical follow-up visits for an average of 22.1 ± 6.4 months.
      Temperatures on the contralateral foot were measured as a control. In this population, there
      were significant differences in skin temperature in both the Charcot (8.30°F, p < 0.001) and
      ulcer groups (5.60°F, p < 0.001) compared with the region overlying the site of pathology on
      the contralateral side. No significant temperature difference was identified in the group
      with asymptomatic loss of protective threshold group and no acute pathology. Temperatures all
      normalized at the time of Charcot quiescence and ulcer healing. Eleven percent of patients in
      the ulcer group re-ulcerated a mean 12.2 ± 6.4 months after initial healing with a
      corresponding significant increase in skin temperature at the clinic visit immediately
      preceding reinjury (p < 0.001). These data suggest that monitoring of the corresponding
      contralateral foot site may provide objective, clinical information before other clinical
      signs of injury can be identified and that infrared dermal thermometry may be predictive of
      neuropathic ulceration.27 Subsequent studies have indicated that elevated skin temperatures
      are directly correlated with location of acute neuropathic osteoarthropathy (Charcot's
      arthropathy) and that temperatures will equilibrate in a predictable manner as acute
      Charcot's arthropathy resolves into a quiescent state.28,29 Furthermore, the difference in
      temperature on the wounded side compared with the corresponding contralateral site decreases
      as the surface area of the wound decreases.30 As a practical measure, the opposite extremity
      has been used in previous studies as a control because it is exposed to the same duration and
      control of diabetes and systemic complications as the affected limb and should represent a
      built-in comparison source. In this manner, the patient serves as his own control. Because
      the disease processes of neuropathic fractures and ulceration involves multiple factors that
      affect lower extremity perfusion and temperature regulation, it would be difficult to
      identify an absolute skin temperature level that could be considered normal or one that could
      be used as a universal reference. For instance, the baseline temperatures for a patient with
      Charcot's fracture may be higher than diabetic patients without this complication or persons
      without diabetes.45-47 In a related study, temperatures assessed by manual palpation were
      identified as a relatively inaccurate means of quantifying skin temperature.47 To that end,
      eleven healthy physicians, eight male with a mean age of 28.6 ± 4.4 years, were enrolled for
      study. These subjects were instructed to palpate two of five steel cylinders of known
      temperature using the volar surface of their hands. The five cylinders, arranged randomly
      were carefully gradated to produce equal, 2, 4 and 6 degree Celsius temperature gradients.
      They were then asked whether the temperature difference between any two cylinders was equal,
      2º, 4º or 6° Celsius. This process was repeated a total of ten times for each participant.
      Subjects correctly estimated the temperature gradient a mean 1.00 ± 0.89 times out of 10
      random attempts. There was not a significant difference between temperature gradient and
      frequency of correct answers (p > 0.05). It was concluded that, while the laying on of hands
      in a clinical setting is a necessary and crucial component of the doctor-patient
      relationship, manual palpation, even in a controlled environment, is not a reliable or
      objective means to assess temperature.

      For this TempTouch IR Thermometry of high-risk diabetic patient self care study the STUDY
      SPECIFIC AIMS were:

        1. To evaluate the effectiveness of a home infrared temperature probe to reduce the
           incidence of diabetic foot ulcers among high-risk patients;

        2. To evaluate the cost of home temperature monitoring compared to standard therapy among
           high-risk patients with diabetes; and

        3. To evaluate patient perceived benefits and satisfaction of home temperature monitoring.
    

Intervention name(s): TempTouch®
Intervention type(s): Device
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single
Primary purpose: Prevention
Keywords: Charcot; foot; ulceration; neuropathy