Risk of radiographic knee osteoarthritis in 12 years:
This clinical prediction model calculates the risk of developing radiographic knee osteoarthritis in 12 years using 6 clinical variables (c-index: 0.60-0.74).
Research authors: Zhang W, McWilliams DF, Ingham SL, Doherty SA, Muthuri S, Muir KR, Doherty M.
Details Formula Study characteristics Files & References
Model author
Model ID
Revision date
MeSH terms
  • Osteoarthritis Of Knee
  • Radiography
  • Clinical Prediction Rule
  • Model type
    Logistic regression (Calculation)
    No Formula defined yet
    Condition Formula

    Additional information

    A 12-year retrospective cohort study was undertaken involving four general practices in North Nottinghamshire.1

    Exclusion criteria:
    People with terminal illness, psychiatric illness and severe dementia were excluded.1

    Study population:
    In total, 424 people were eligible for the study.1 Individuals were recruited from two baseline community postal questionnaire studies for knee pain.2,3 Baseline data were collected between 1996 and 1999 from 9429 adults aged 40-79 years on the general practice registers. A follow-up survey was undertaken during 2007–2008 in 5479 individuals who are still registered with the general practices and eligible for the study. Radiographs of both knees at baseline and follow-up were obtained from 424 participants according to availability and willingness to participate.

    1 Zhang W, McWilliams DF, Ingham SL, et al. Nottingham knee osteoarthritis risk prediction models. Ann Rheum Dis. 2011;70(9):1599-604.
    2 O’Reilly SC, Muir KR, Doherty M. Screening for pain in knee osteoarthritis: which question? Ann Rheum Dis. 1996:55:931-3.
    3 Thomas KS, Muir KR, Doherty M, et al. Home based exercise programme for knee pain and knee osteoarthritis: randomised controlled trial. BMJ. 2002;325:752.

    Study Population

    Total population size: 424
    Males: {{ model.numberOfMales }}
    Females: {{ model.numberOfFemales }}

    Continuous characteristics

    Name Mean SD Unit
    Age 56.8 7.9 years
    Body mass index 25.5 3.5 kg/m2
    Name LL Q1 Median Q3 UL Unit
    Occupational risk 0 2 3 4 4 risk score
    Duration of follow-up 7 12 12 years

    Categorical characteristics

    Name Subset / Group Nr. of patients
    Previous serious knee injury Yes 25
    No 399
    Familial osteoarthritis Yes 136
    No 288
    Risk of radiographic knee osteoarthritis in 12 years:
    Refer to Intended Use for instructions before use
    Evidencio B.V., Irenesingel 19, 7481 GJ, Haaksbergen, the Netherlands

    Related files

    Risk of radiographic knee osteoarthritis in 12 years:

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    Risk of radiographic knee osteoarthritis in 12 years:

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    Outcome stratification

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    Conditional information

    Result interpretation

    How this model should be used:
    This model may be applied at the individual level to predict the risk, and to encourage risk reduction. It may also be used at the population level, with reference to other relative risks from published studies, to estimate the potential population risk reduction that may be gained by primary prevention of the major risk factors of knee OA.

    Model performance:
    Upon internal validation (N=424), the area under the ROC curve showed a moderate discriminative ability of the model (c-index: 0.69, 95% CI 0.62 to 0.76).1 External validation was performed on two different cohorts: the (2) Nottingham Genetics of Osteoarthritis and Lifestyle (GOAL) case-control study population (N=3174)2 and (3) the Osteoarthritis Initiative (OAI) cohort study population (N=4796).3  External validation resulted in c-indices of 0.60 (0.55 to 0.64) and 0.74 (0.72 to 0.76), respectively. The Hosmer–Lemeshow χ2 statistic for goodness-of-fit showed good calibration in all three patient cohorts.

    1 Zhang W, McWilliams DF, Ingham SL, et al. Nottingham knee osteoarthritis risk prediction models. Ann Rheum Dis. 2011;70(9):1599-604.
    2 Zhang W, Robertson J, Doherty S, et al. Index to ring finger length ratio and the risk of osteoarthritis. Arthritis Rheum. 2008;58:137-44.
    3 Fawaz-Estrup F. The osteoarthritis initiative: an overview. Med Health R I. 2004;87:169-71.

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    Calculations alone should never dictate patient care, and are no substitute for professional judgement. See our full disclaimer.

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