D. Discussion
V. Conclusions and Future Research
V. CONCLUSI ONS AND F V. CONCLUSI ONS AND F
V. CONCLUSI ONS AND F UTURE RESEARCH UTURE RESEARCH UTURE RESEARCH UTURE RESEARCH
A. Creation of a stepwise and checklist (READER) for the development and critical analysis of clinical decision/ prediction rules.
Clinical decision rules are a valuable, although rather recent, clinical decision support tool created to reduce clinical decision making uncertainty, simplify and increase the clinicians’ diagnostic and prognostic accuracy (Beattie et al, 2006; Childs et al, 2006; Jaeschke et al, 2002; Lijmer et al, 1999; Reilly et al, 2006; Sackett et al, 1996; Stiell, 2000; Stiell, 2007; Wasson et al, 1985)- providing a standardized approach for the probabilty estimation of an outcome development (Reynolds, 2001)
.
Due to its relative newness, we have verified that insufficient efforts for its development methodology and reporting standardization have been made - one of the most important features for a more widespread utilization and implementation.
With our work, we have proposed for the first time a structured stepwise for clinical decision rule’s derivation (in 10 steps), validation (in 8 steps) and impact analysis (in 9 steps) and a checklist, with 29 items, to help guiding in their creation and analysis.
Therefore, we wish, as a future project, to perform a systematic review around the clinical decision rule’s development and assessment topic and, if possible, to develop a more definitive checklist and stepwise through an expert consensus.
After that essential step, we wish to apply the resultant checklist to a randomized sample of clinical decision rules developed since the beginning of its development until nowadays in order to assess if occurred any improvement in the reporting quality and the most common missing items. That way, we can verify the impact of the 2 clinical decision rule’s development methodology proposal publications (Laupacis et al, 1997; Wasson et al, 1985)
and highlight the most common faults in order to improve their development and reporting in the future. Due to time restrictions, and to the fact that this subject matter was not this thesis core, it was not possible to perform it before the time limit.
B. Pathophysiology of diabetic foot ulcer development.
Through a literature review, we have concluded that diabetic foot ulceration has an intricate pathophysiologic process in which diabetic neuropathy, peripheral vascular disease and trauma frequently have special roles (Boulton, 2004 a, 2006; Boulton et al, 2008 a, 2008 b; Bowering, 2001; Frykberg et al, 2006; Khanolkar et al, 2008; Morbach, 2003; SIGN, 2001).
C. Systematic review of predictive factors for diabetic foot ulcer development.
In the systematic review we have performed (chapter III, section B), with the aim of retrieving a list of all possible predictive variables of ulceration, 60 studies assessing more than 100 variables were included.
The performed systematic review points to a similar conclusion of the pathophysiology section - the most consistently associated variables with foot ulcer development were:
nephropathy, several diabetic neuropathy tests, edema, therapeutic footwear, foot deformities, callus, tinea pedis, absent foot palpable pulses, previous foot complications and dermal thermometry.
Despite the large quantity of studies available, the presented evidence showed various limitations. Something as simple and vital as foot ulcer definition was absent in half of the studies or presented an enormous variety.
The retrieved studies were agglomerated into 5 different outcomes and they presented various study designs with a diverse range of quality. Additionally, several variables collection and diagnostic cut-offs showed inconsistency (foot pulses, vibration perception threshold, Semmes-Weinstein monofilament, plantar peak pressure…) and the association of various variables revealed to be not consistent among studies or was assessed only by one study (in more than 90% of the variables).
As a result, we believe that there is a long way to run in order to improve research development in this field, such as performing a consensus for selecting the most appropriate foot ulcer definition and carrying out studies to better outline the best cut-offs for the most essential variables (HbA1C, diabetic neuropathy tests, foot pulses, plantar peak pressures, ankle brachial index…) and to evaluate the true impact of preventive measures (education, therapeutic footwear, multidisciplinar team care, chiropodist care).
D. Systematic review of the existing stratifications of risk degree for diabetic foot ulcer development.
Foot ulcer risk stratification systems are an indispensable tool for the patient with diabetes screening. The core variables of the 5 retrieved stratification systems are very similar (diabetic neuropathy, peripheral vascular disease, foot deformity, previous ulcer and previous lower extremity amputation) and are in agreement with the systematic review results. However, little has been done in their validation.
Only 4 articles evaluate the effectiveness of a determined stratification system in separate and expressed it in different forms (odds ratio; diagnostic accuracy measures as sensitivity, specificity, likelihood ratios; area under the receiver operating curve);
which has difficult their results’ comparison. Additionally, all the stratification systems are only at a level 4 of evidence.
E. Validation and optimization of the Boyko’s foot ulcer development risk stratification system.
We have chosen to validate and optimize the Boyko’s et al proposed stratification system (choice justification present in chapter III, section B discussion) and concluded that this is an excellent tool to identify patients at high-risk, in both gender, and that the inclusion of a variable regarding footwear could improve it.
As a major limitation this study presents its retrospective nature and the high-risk context were it was developed. However, this was the first and only attempt to externally validate and optimize this stratification system elevating it to a level 3 of evidence.
Therefore we particularly aspire to validate the original model proposed by Boyko prospectively and in a larger population (if possible with a higher representation of patients with type 1 diabetes) and establish if the inclusion of a variable concerning the footwear and other variables resulting from the systematic review (such as other diabetic neuropathy tests, limited joint mobility, peripheral vascular disease tests…) can in fact improve it.
A foot ulcer risk stratification system choice and validation is also essential to a future project: a risk perception study comparing the patients’ risk auto-perception with the one retrieved by the selected stratification system.
With this research we aim to create a protocol, to standardize concepts and procedures, and a database of all the diabetic patients followed in the hospital and health centers connected to our hospital in order to promote a better communication, resource allocation and guarantee an improvement in the diabetic foot prevention in our impact area.
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