A Combined Randomised and Observational Study of Surgery for Fractures In the distal Radius in the Elderly (CROSSFIRE): a statistical analyses plan

BACKGROUND: We are performing a combined randomised and observational study comparing internal fixation to non-surgical management for common wrist fractures in older patients. This paper describes the statistical analysis plan. METHODS/DESIGN: A Combined Randomised and Observational Study of Surgery for Fractures In the distal Radius in the Elderly (CROSSFIRE) is a randomised controlled trial comparing two types of usual care for treating wrist fractures in older patients, surgical fixation using volar locking plates and non-surgical treatment using closed reduction and plaster immobilisation. The primary aim of this comparative-effectiveness study is to determine whether surgery is superior to non-surgical treatment with respect to patient-reported wrist function at 12 months post treatment. The secondary outcomes include radiographic outcomes, complication rates and patient-reported outcomes including quality of life, pain, treatment success and cosmesis. Primary analysis will use a two-sample t test and an intention-to-treat analysis using the randomised arm of the study. Statistical analyses will be two-tailed and significance will be determined by p < 0.05. Sensitivity analyses will be conducted to assess for differences in intention-to-treat, per-protocol and as-treated analyses. Sensitivity analyses will also be conducted to assess selection bias by evaluating differences in participants between the randomised and observational study arms, and for bias relating to any missing data. An economic analysis will be conducted separately if surgery is shown to provide superior outcomes to a level of clinical significance. DISCUSSION: This statistical analysis plan describes the analysis of the CROSSFIRE study which aims to provide evidence to aid clinical decision-making in the treatment of distal radius fractures in older patients. TRIAL REGISTRATION: CROSSFIRE was approved by The Hunter New England Human Research Ethics Committee (HNEHREC Reference No: 16/02/17/3.04). Registered on 22 July 2016 with The Australian and New Zealand Clinical Trials Registry (ANZCTR Number; ACTRN12616000969460). This manuscript is based on v.11 of the statistical analysis plan. A copy of v.11, signed by the chief investigator and the senior statistician is kept at the administering institution.