Dfi clinical Trial Differs from csssi trial



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tarix15.12.2016
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DFI Clinical Trial

  • Differs from cSSSI trial

    • Risk factors (vascular, neuropathy, diabetes itself)
    • Adjunctive therapy
      • Debridement and surgery are integral
      • Wound care
      • Off-loading


Desirable Features of a Study

  • Designed to optimize enrollment:

    • Includes most types of diabetic foot infections (cellulitis, infected ulcer, deep tissue infection)
    • Allows inpatient or outpatient therapy
    • Allows intravenous or oral therapy
    • Allows additional antibiotic agents for resistant organisms


Study Inclusion Criteria - 1

  • Male or female over age 18

  • Be able & willing to give informed consent and complete all study activities

  • Diabetes mellitus (by ADA criteria); either type, any treatment acceptable

  • Infected lesion of lower extremity:

    • cellulitis, deep soft tissue infection, infected ulcer, septic arthritis, paronychia, abscess


Study Inclusion Criteria - 2

  • Infected lesion can

    • require extensive debridement or surgery, but not complete resection/amputation
    • be open or closed
    • be anywhere on foot
    • be multiple, but select one “study” lesion
    • have been treated with potentially effective antibiotic, but only for <72 hours


Study Exclusion Criteria

  • Local (lower extremity) conditions

    • Critical ischemia of affected limb*
    • Expectation that entire infection will be resected or amputated
    • > 72 h of agent active against all pathogens
    • Infected device that can/will not be removed
    • Require additional antibiotic for any reason
    • Presence of extensive dry/wet gangrene
    • --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------


Exclusion Criteria (Ischemia)

  • Critical ischemia of affected limb, defined as:

    • Absence of palpable posterior tibial and dorsalis pedis pulses
    • Absent or abnormal Doppler waveforms
    • + toe blood pressure < 45 mm Hg


Osteomyelitis

  • Occurs in > ¼ of diabetic foot infections

  • Can be difficult to diagnose

  • Can be more difficult to eradicate

    • requires more prolonged antibiotic therapy
      • no good clinical data on required duration
      • 4 weeks likely adequate; less if bone resected
    • may require surgical debridement/resection


Exclusion Criteria (Osteomyelitis)

  • Open wound, bone visible

  • Open wound, probe to bone positive

  • Baseline X-ray or MRI read as active osteomyelitis (criteria for osteomyelitis to be established in protocol)

  • Nuclear scan alone is not sufficient to exclude osteomyelitis



“I shall not today attempt to define the kinds of material (pornography) - but I know it when I see it.”

  • “I shall not today attempt to define the kinds of material (pornography) - but I know it when I see it.”

  • Justice Potter Stewart (1915-1985)



Diagnostic Studies

  • Plain X-ray

  • Probe to bone for open lesions

  • Culture/sensitivity testing

  • Wound description (photography)/ wound score

  • Vascular evaluation



Wound Cultures

  • Obtain from all enrolled patients- no more than 24 hours prior to enrollment

  • Set-up for aerobes & anaerobes at local lab

  • Swab specimens are not acceptable

  • Curretage of wound base

    • after cleansing/debriding scrape with scalpel
    • send tissue on blade in sterile container
  • Tissue specimens: obtain at bedside/OR

  • Aspiration: for secretions, cellulitis



Wound Scoring System

  • Designed to give objective wound score

  • Includes quantified

    • General wound parameters (description)
    • Peripheral pulses assessment
    • Wound measurements
    • Wound infection score


Probe to Bone

  • One study* in 76 patients:

    • Sensitivity 66%; Specificity 85%
    • + Predict. value 89%; - Predict. value 56%
  • Technique: 14 cm 5 F sterile metal probe

    • Done prior to wound debridement (x eschar)
    • Use routine aseptic procedures; clinic/bedside
    • Holding like pencil, gently probe wound
    • Hard, gritty structure in wound, w/o apparent intervening soft tissue, is + test
    • Avoid if closed/surgically exposed wounds
    • -------------------------------------------------------------
  • * Grayson et al, JAMA 1995;273:721-3



Treatment

  • Drug vs. comparator (gold standard) – IV or PO

  • Can add other agents for activity against organisms not covered by the study drug

  • 7 – 21 days of antibiotics; 14 days is usual duration



Adjunctive Therapy

  • Debridement/surgery

  • Dressing changes

  • Off-loading

  • Not allowed: topical antibiotic, anti-septic, or other antimicrobial agents (i.e., Betadine)



Topical Therapy

  • Antimicrobials

    • No topical antibiotics (mupirocin, sulfa, aminoglycosides, etc.)
    • No topical antiseptics (H2O2, iodophors, chlorhexidine, silver, etc.)
  • Others (non-antimicrobial)

    • Agents such as becaplermin, collagen, etc. are allowed, but not encouraged


Wound Dressings

  • Many available types- none proven best

  • Moist environment preferred

  • No antimicrobial products allowed

  • Moist-to-damp saline dressing adequate

  • Other types permissible



Wound Off-Loading

  • Helpful to curing infection and crucial healing wound

  • Many devices used- none proven best

    • total contact cast
    • special shoes/boots
    • crutches, wheelchair, etc


Efficacy Evaluations (1)

  • Follow-up for test-of-cure at 14 – 21 days after end of therapy

  • Clinical response to therapy – defined as resolution of pre-therapy clinical signs and symptoms of infection

  • Final categories: cured, failed, indeterminate



Efficacy Evaluations (2)

  • Surgical debridement is allowed during the trial and is considered part of standard care

  • Complete resection of the infected area will remove patient from the trial



Sample Size

  • Assume 80% success rate for comparator

  • Difference in cure rate of <10% will be considered equivalent

  • ?Criteria for superiority




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