Validity of Cardiovascular Risk Prediction Models in Kidney Transplant Recipients

Table 1

Criteria for determining risk of bias (adapted from the QUIPS tool*).

Potential bias	Areas to be considered
Study participation; The study sample adequately represents the population of interest	(i) Adequate participation in the study by eligible persons; (ii) Description of the source population or population of interest; (iii) Description of the baseline study sample; (iv) Adequate description of sampling time frame and recruitment; (v) Adequate description of the period and place of recruitment; (vi) Adequate description of inclusion and exclusion criteria
Study attrition; The study data available (i.e., participants not lost to follow-up); adequately represent the study sample	(i) Adequate response rate for study participants; (ii) Description of attempts to collect information on patients who dropped out; (iii) Reasons for loss to follow-up are provided; (iv) Adequate description of participants lost to follow-up; (v) There are no important differences between participants who completed the; study and those who did not
Prognostic factor measurement; The prognostic factor is measured in a similar way for all participants	(i) A clear definition or description of the PF is provided; (ii) Method of PF measurement is adequately valid and reliable; (iii) Continuous variables are reported or appropriate cut points are used; (iv) The method and setting of measurement of PF are the same for all study; participants; (v) Adequate proportion of the study sample has complete data for the PF; (vi) Appropriate methods of imputation are used for missing PF data
Outcome measurement; The outcome of interest is measured in a similar way for all participants	(i) A clear definition of the outcome is provided; (ii) Method of outcome measurement used is adequately valid and reliable; (iii) The method and setting of outcome measurement are the same for all study; participants
Study confounding; Important potential confounding factors are appropriately accounted for	(i) All important confounders are measured; (ii) Clear definitions of the important confounders measured are provided; (iii) Measurement of all important confounders is adequately valid and reliable; (iv) The method and setting of confounding measurement are the same for all study participants; (v) Appropriate methods are used if imputation is used for missing confounder data; (vi) Important potential confounders are accounted for in the study design; (vii) Important potential confounders are accounted for in the analysis
Statistical analysis and reporting; The statistical analysis is appropriate, and all primary outcomes are reported	(i) Sufficient presentation of data to assess the adequacy of the analytic strategy; (ii) Strategy for model building is appropriate and is based on a conceptual; framework or model; (iii) The selected statistical model is adequate for the design of the study; (v) There is no selective reporting of results

∗Adapted from reference [24].
QUIPS: Quality in Prognosis Studies; PF: prognostic factor.