Cited by 63Diabetic Foot Ulcer Assessment and ManagementDiabetes Management and ResearchDiabetes, Cardiovascular Risks, and Lipoproteins

Development and validation of risk prediction equations to estimate future risk of blindness and lower limb amputation in patients with diabetes: cohort study

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Hippisley-Cox, J., Coupland, C.·2015·BMJ

Abstract

STUDY QUESTION: Is it possible to develop and externally validate risk prediction equations to estimate the 10 year risk of blindness and lower limb amputation in patients with diabetes aged 25-84 years? METHODS: This was a prospective cohort study using routinely collected data from general practices in England contributing to the QResearch and Clinical Practice Research Datalink (CPRD) databases during the study period 1998-2014. The equations were developed using 763 QResearch practices (n=454,575 patients with diabetes) and validated in 254 different QResearch practices (n=142,419) and 357 CPRD practices (n=206,050). Cox proportional hazards models were used to derive separate risk equations for blindness and amputation in men and women that could be evaluated at 10 years. Measures of calibration and discrimination were calculated in the two validation cohorts. STUDY ANSWER AND LIMITATIONS: Risk prediction equations to quantify absolute risk of blindness and amputation in men and women with diabetes have been developed and externally validated. In the QResearch derivation cohort, 4822 new cases of lower limb amputation and 8063 new cases of blindness occurred during follow-up. The risk equations were well calibrated in both validation cohorts. Discrimination was good in men in the external CPRD cohort for amputation (D statistic 1.69, Harrell's C statistic 0.77) and blindness (D statistic 1.40, Harrell's C statistic 0.73), with similar results in women and in the QResearch validation cohort. The algorithms are based on variables that patients are likely to know or that are routinely recorded in general practice computer systems. They can be used to identify patients at high risk for prevention or further assessment. Limitations include lack of formally adjudicated outcomes, information bias, and missing data. WHAT THIS STUDY ADDS: Patients with type 1 or type 2 diabetes are at increased risk of blindness and amputation but generally do not have accurate assessments of the magnitude of their individual risks. The new algorithms calculate the absolute risk of developing these complications over a 10 year period in patients with diabetes, taking account of their individual risk factors. FUNDING, COMPETING INTERESTS, DATA SHARING: JH-C is co-director of QResearch, a not for profit organisation which is a joint partnership between the University of Nottingham and Egton Medical Information Systems, and is also a paid director of ClinRisk Ltd. CC is a paid consultant statistician for ClinRisk Ltd.

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  • These calculators estimate 10-year risk of microvascular and macrovascular complications.

    “These calculators can be used to predict 10-year risk for microvascular and macrovascular complications.”

    From Type 1 diabetes (2018) · cites this paper as [129]

    The Discussion says the paper's equations predict 10-year risks of blindness and lower-limb amputation in people with diabetes. It does not say these calculators predict macrovascular complications; the Introduction describes cardiovascular and stroke risk as assessed by other tools. (LLM, conf=0.88)

    Experimental — accuracy not yet measured
  • The QDiabetes and QRISK3 online tools were built using prospective general practice data from 803,044 people with diabetes, including 44,440 with type 1 diabetes.

    “Two examples are the QDiabetes129 and QRISK3130 web calculators that were developed with a prospective general practice dataset of 803 044 people with diabetes (44 440 with type 1 diabetes).”

    From Type 1 diabetes (2018) · cites this paper as [129]

    The Results (Overall study population) give 454,575 patients in the derivation cohort and 142,419 and 206,050 in two validation cohorts, totaling 803,044. Table 1 (Baseline characteristics) gives 44,430 patients with type 1 diabetes across those cohorts, not 44,440. The web calculator is documented, but the 803,044 figure includes validation patients rather than only patients used to develop its equations. (LLM, conf=0.90)

    Experimental — accuracy not yet measured
  • Research has found further non-glycaemic factors that raise complication risk.

    “Several studies127–130 have identified additional non-glycaemic risk factors for the development of complications.”

    From Type 1 diabetes (2018) · cites this paper as [129]

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Research works printed but not linked: 1

  1. [33]Hosmer D, Lemeshow S, May S. Applied survival analysis: regression modelling of time to event data. Wiley, 2007.

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Authors
Hippisley-Cox, J., & Coupland, C.
Affiliations
University of Nottingham (GB)
Venue
BMJ
Publisher
BMJ
Published
2015-11-11
Volume
351
Issue
nov11 1
Pages
h5441-h5441
ISSN
1756-1833 (ISSN-L)
OpenAlex
W2136816386
Cited by
63
References
57
Citations by year
2026: 3 · 2025: 3 · 2024: 8 · 2023: 2 · 2022: 9 · 2021: 9 · 2020: 4 · 2019: 6 · 2018: 8 · 2017: 4 · 2016: 6 · 2015: 1
FWCI
5.49
Type
journal article
Language
en
Open access
Licence
cc-by
Locations
  • BMJ (publishedVersion, cc-by)
  • Europe PMC (PubMed Central) (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • Repository@Nottingham (University of Nottingham) (publishedVersion, cc-by)
  • Repository@Nottingham (University of Nottingham) (submittedVersion, cc-by)
  • Nottingham ePrints (University of Nottingham) (submittedVersion, cc-by)
Topics
  • Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Diabetic Foot Ulcer Assessment and Management
  • Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Diabetes Management and Research
  • Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Diabetes, Cardiovascular Risks, and Lipoproteins
Keywords
diabetes mellitus, blindness, lower limb amputation, risk prediction equations, absolute risk estimation, type 1 diabetes, type 2 diabetes, diabetes complications, risk factors, sex differences, external validation, routine clinical data, Clinical Practice Research Datalink, general practice records, risk stratification, discrimination and calibration, information bias, missing data
MeSH terms
Adult, Aged, Aged, 80 and over, Algorithms, Amputation, Surgical, Blindness, Diabetes Mellitus, Type 1, Diabetes Mellitus, Type 2, England, Female, Humans, Male, Middle Aged, Predictive Value of Tests, Prospective Studies, Proportional Hazards Models, Risk Assessment, Lower Extremity

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