Acta Orthopaedica, 88:6, 578-580, DOI: 10.1080/17453674.2017.1361130

The Cox model is better than the Fine and Gray model when estimating relative revision risks from arthroplasty register data

Jonas Ranstam & Otto Robertsson
Hip Knee

Background and purpose — Analysis of the revision-free survival of knee and hip prostheses has traditionally been performed using Kaplan–Meier analysis and Cox regression. The competing risk problem that is related to patients who die during follow-up has recently been increasingly discussed, not least with regard to the problem of choosing a suitable statistical method for the analysis. We compared the results from analyses of Cox models and Fine and Gray models.

Methods — We used data simulation based on parameter estimates from the Swedish Knee Arthroplasty Register and assessed hypothetical effects of the studied risk factors.

Results — The Cox model provided more adequate results.

Interpretation — The parameter estimates from the Fine and Gray model can be misleading if interpreted in terms of relative risk.

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