Measuring the accuracy of different ways to identify the ‘at‐risk’ foot in routine clinical practice

Leese, Graham; Cochrane, Lindy; Mackie, Anna; Stang, Duncan; Brown, Kimberly; Green, V.

doi:10.1111/j.1464-5491.2011.03297.x

Cited by 21 publications

(71 citation statements)

References 19 publications

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“…It is also a relatively new development of meta-analysis methods; although IPD meta-analyses have been used for some time, they have most often been used for RCT data, where the recommendation is to use a two-step method to avoid comparison of patient groups that were not randomised together. 45 Two large data sets were contributed to this project but access to one was constrained, 46,47 with around 3412 patients' data only available to the authors via a safe haven facility. The safe haven facility allowed the analyses of data to obtain an estimate of effect but not to remove or copy the data.…”

Section: Methods Of Meta-analysis: One-step Versus Two-step Methodsmentioning

confidence: 99%

“…60 In multivariate models, the effect of kidney problems was not consistent, being apparently protective against ulceration in some cases 5,61 but predictive in others, for example. 3,46,47,62 Again, it was decided to drop kidney problems from the primary model but retain it for secondary analyses.…”

Section: Chapter 4 Development Of the Modelmentioning

confidence: 99%

“…3,5,61,62,[72][73][74][75] Data from a ninth study 46,47 were made available to the Data Management Committee via Safe Haven, a data-management system. Finally, a 10th corresponding author was not granted permission to share the data from a cohort study by the Institutional Review Board 48 but was able to contribute to the meta-analysis by subjecting the data to the same analytical procedures as all other studies to provide estimates of effect, which could be incorporated into the final (meta) analysis.…”

Section: Development Of the Modelmentioning

confidence: 99%

“…Two sets of authors 5,46,47 collected their data in the same geographical area; common patient encrypted identifiers were placed in a safe haven and merged with the data set of the Leese study in order to exclude duplicated patients.…”

Section: Data Preparationmentioning

confidence: 99%

“…Ascertainment of the outcome variable (ulcer present/ulcer absent) was performed using the same electronic register. 46,47 A total of 1944 patients with a diagnosis of type 1 or type 2 diabetes mellitus were recruited from a diabetes outpatient clinic in a geriatric unit of an Italian hospital. The data were collected by diabetologists and research fellows between 1995 and 2000.…”

Section: Derivation Cohort Studiesmentioning

confidence: 99%

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A systematic review and individual patient data meta-analysis of prognostic factors for foot ulceration in people with diabetes: the international research collaboration for the prediction of diabetic foot ulcerations (PODUS)

Crawford

Cézard

Chappell

et al. 2015

Health Technol Assess

158

196

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BackgroundAnnual foot risk assessment of people with diabetes is recommended in national and international clinical guidelines. At present, these are consensus based and use only a proportion of the available evidence.ObjectivesWe undertook a systematic review of individual patient data (IPD) to identify the most highly prognostic factors for foot ulceration (i.e. symptoms, signs, diagnostic tests) in people with diabetes.Data sourcesStudies were identified from searches of MEDLINE and EMBASE.Review methodsThe electronic search strategies for MEDLINE and EMBASE databases created during an aggregate systematic review of predictive factors for foot ulceration in diabetes were updated and rerun to January 2013. One reviewer applied the IPD review eligibility criteria to the full-text articles of the studies identified in our literature search and also to all studies excluded from our aggregate systematic review to ensure that we did not miss eligible IPD. A second reviewer applied the eligibility criteria to a 10% random sample of the abstract search yield to check that no relevant material was missed. This review includes exposure variables (risk factors) only from individuals who were free of foot ulceration at the time of study entry and who had a diagnosis of diabetes mellitus (either type 1 or type 2). The outcome variable was incident ulceration.ResultsOur search identified 16 cohort studies and we obtained anonymised IPD for 10. These data were collected from more than 16,000 people with diabetes worldwide and reanalysed by us. One data set was kept for independent validation. The data sets contributing IPD covered a range of temporal, geographical and clinical settings. We therefore selected random-effects meta-analysis, which assumes not that all the estimates from each study are estimates of the same underlying true value, but rather that the estimates belong to the same distribution. We selected candidate variables for meta-analysis using specific criteria. After univariate meta-analyses, the most clinically important predictors were identified by an international steering committee for inclusion in the primary, multivariable meta-analysis. Age, sex, duration of diabetes, monofilaments and pulses were considered most prognostically important. Meta-analyses based on data from the entire IPD population found that an inability to feel a 10-g monofilament [odds ratio (OR) 3.184, 95% confidence interval (CI) 2.654 to 3.82], at least one absent pedal pulse (OR 1.968, 95% CI 1.624 to 2.386), a longer duration of a diagnosis of diabetes (OR 1.024, 95% CI 1.011 to 1.036) and a previous history of ulceration (OR 6.589, 95% CI 2.488 to 17.45) were all predictive of risk. Female sex was protective (OR 0.743, 95% CI 0.598 to 0.922).LimitationsIt was not possible to perform a meta-analysis using a one-step approach because we were unable to procure copies of one of the data sets and instead accessed data via Safe Haven.ConclusionsThe findings from this review identify risk assessment procedures that can reliably inform national and international diabetes clinical guideline foot risk assessment procedures. The evidence from a large sample of patients in worldwide settings show that the use of a 10-g monofilament or one absent pedal pulse will identify those at moderate or intermediate risk of foot ulceration, and a history of foot ulcers or lower-extremity amputation is sufficient to identify those at high risk. We propose the development of a clinical prediction rule (CPR) from our existing model using the following predictor variables: insensitivity to a 10-g monofilament, absent pedal pulses and a history of ulceration or lower-extremities amputations. This CPR could replace the many tests, signs and symptoms that patients currently have measured using equipment that is either costly or difficult to use.Study registrationThis study is registered as PROSPERO CRD42011001841.FundingThe National Institute for Health Research Health Technology Assessment programme.

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Section: Methods Of Meta-analysis: One-step Versus Two-step Methodsmentioning

confidence: 99%

Section: Chapter 4 Development Of the Modelmentioning

confidence: 99%

Section: Development Of the Modelmentioning

confidence: 99%

Section: Data Preparationmentioning

confidence: 99%

Section: Derivation Cohort Studiesmentioning

confidence: 99%

See 3 more Smart Citations

A systematic review and individual patient data meta-analysis of prognostic factors for foot ulceration in people with diabetes: the international research collaboration for the prediction of diabetic foot ulcerations (PODUS)

Crawford

Cézard

Chappell

et al. 2015

Health Technol Assess

158

196

View full text Add to dashboard Cite

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When and how to audit a diabetic foot service

Leese

Stang

2016

Diabetes Metabolism Res

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Quality improvement depends on data collection and audit of clinical services to inform clinical improvements. Various steps in the care of the diabetic foot can be used to audit a service but need defined audit standards. A diabetes foot service should have risk stratification system in place that should compare to the population-based figures of 76% having low-risk feet, 17% moderate risk and 7% being at high risk of ulceration. Resources can then be directed towards those with high-risk feet. Prevalence of foot ulceration needs to be audited. Community-based studies give an audit standard of around 2%, with 2 to 9% having had an ulcer at some stage in the past. Amputation rates should be easier to measure, and the best results are reported to be around 1.5-3 per 1000 people with diabetes. This is a useful benchmark figure, and the rate has been shown to decrease by approximately a third over the last 15 years in some centres. Ulceration rates and ulcer healing rates are the ultimate outcome audit measure as they are always undesirable, whilst occasionally for defined individuals, an amputation can be a good outcome. In addition to clinical outcomes, processes of care can be audited such as provision of clinical services, time from new ulcer to be seen by health care professional, inpatient foot care or use of antibiotics. Measurement of clinical services can be a challenge in the diabetic foot, but it is essential if clinical services and patient outcomes are to be improved.

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Amputation-free survival in 17,353 people at high risk for foot ulceration in diabetes: a national observational study

et al. 2018

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Aims/hypothesisOur aim was to investigate amputation-free survival in people at high risk for foot ulceration in diabetes (‘high-risk foot’), and to compare different subcategories of high-risk foot.MethodsOverall, 17,353 people with diabetes and high-risk foot from January 2008 to December 2011 were identified from the Scotland-wide diabetes register (Scottish Care Information-Diabetes: N = 247,278). Participants were followed-up for up to 2 years from baseline and were categorised into three groups: (1) those with no previous ulcer, (2) those with an active ulcer or (3) those with a healed previous ulcer. Participants with prior minor or major amputation were excluded. Accelerated failure time models were used to compare amputation-free survival up to 2 years between the three exposure groups.ResultsThe 2 year amputation-free survival rate in all people with diabetes with high-risk foot was 84.5%. In this study group, 270 people (10.0%) had an amputation and 2424 (90.0%) died during the 2 year follow-up period. People who had active and healed previous ulcers at baseline had significantly lower 2 year amputation-free survival compared with those who had no previous ulcer (both p < 0.0001). The percentage of people who died within 2 years for those with healed ulcer, active ulcer or no baseline ulcer was 22.8%, 16% and 12.1%, respectively.Conclusions/interpretationIn people judged to be at high risk of foot ulceration, the risk of death was up to nine times the risk of amputation. Death rates were higher for people with diabetes who had healed ulcers than for those with active ulcers. However, people with active ulcers had the highest risk of amputation.Electronic supplementary materialThe online version of this article (10.1007/s00125-018-4723-y) contains peer-reviewed but unedited supplementary material, which is available to authorised users.

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Measuring the accuracy of different ways to identify the ‘at‐risk’ foot in routine clinical practice

Abstract: Integrated foot risk scores are more sensitive than individual clinical criteria in predicting future foot ulceration and are likely to be better screening tools, where excluding false negative results is of paramount importance.

Cited by 21 publications

References 19 publications

A systematic review and individual patient data meta-analysis of prognostic factors for foot ulceration in people with diabetes: the international research collaboration for the prediction of diabetic foot ulcerations (PODUS)

A systematic review and individual patient data meta-analysis of prognostic factors for foot ulceration in people with diabetes: the international research collaboration for the prediction of diabetic foot ulcerations (PODUS)

When and how to audit a diabetic foot service

Amputation-free survival in 17,353 people at high risk for foot ulceration in diabetes: a national observational study

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