Survival After Surgical Treatment of Axis Fractures in Elderly

May 18, 2017 updated by: Uppsala University

Survival After Surgical Treatment of Axis Fractures in Elderly: A National Registry Based Cohort Study

Fractures of the second cervical vertebra (C2) are the most common spinal fracture among the elderly. Non-surgical treatment comprises of cervical collar treatment for 12 weeks, while surgical treatment for elderly could mean posterior fixation C1-C2 without collar treatment or anterior screw osteosynthesis C2 with 6 weeks of collar treatment. A meta-analysis of retrospective studies has recently found an improved survival with surgical treatment. This national registry study is designed to estimate the survival of non-surgical and surgical treatment in a population-based cohort.

Study Overview

Detailed Description

The Swedish National Patient Registry (NPR) is hosted by the Swedish Agency of Health and Welfare and contains all patient contacts within Sweden with a coverage of >90% for orthopaedic diagnoses. Registered are main diagnosis and co-morbidity using the ICD-9 code until 1996 and from 1997 onward ICD-10 codes. Treatment is coded since 1996 using the Swedish classification of surgical procedures. Furthermore, information on hospitalisation time is available from the registry.

In the Swedish Cause of Death Registry (CDR) all deaths in Sweden are registered with date of death and cause of death. While date of death coverage is complete, the cause of death has only 46% agreement with the final hospital diagnosis.

All patients with the main diagnosis of C2 fracture (ICD-10: S12.1) treated between January 1st 1996 to December 31st 2014 are extracted from the NPR and merged with the CDR for incident deaths. Prior to data transmission, the Swedish Agency of Health and Welfare anonymised the individual personal identification numbers using a key which remained with the Agency.

Invalid age data will be excluded either due to missing entries or mismatch with date of death. Multiple admissions (cases with same identification number but more than 12 months between admissions) and duplicate entries (cases with same identification number) will be removed from the dataset, after valuable co-morbidity data from the duplicate entries were stored in the original record. Duplicate entries originate from separate recordings from each hospital if the patient is referred to a specialised hospital. Furthermore, primarily non-surgically treated cases with a change of treatment modality are registered as surgical patients. The registered hospitalisation time for these patients is the combined non-surgical and surgical in-hospital treatment period.

From each record the Charlson Comorbidity Index (CCI) is calculated. Using Swedish surgical procedure codes for spinal fusion ("NAG") and spinal osteosynthesis ("NAJ") patients receiving surgical treatment were marked, and the cohort divided into two groups receiving non-surgical or surgical treatment.

The age distribution differences of patients with C2-fractures treated surgically and non-surgically was visualised with a density distribution plot. A logit logistic regression analysis identified covariates of surgical treatment assignment and was presented with 95% confidence intervals (C.I.) and statistical probability p. Goodness-of-fit of the model was presented with pseudo-r2 according to McFadden.

Using the Kaplan-Meier method for non-surgical and surgical treatment mean survival, as well as survival rate at 3 months, 1 year, and 2 years was determined, and visualised using a Kaplan-Meier plot with 99% C.I. With the Cox proportional hazards regression method multiple covariates contributing to survival are entered and hazard ratio (HR) presented with 95% C.I. and probability p. As relevant covariates for survival besides surgical treatment age, gender, spinal cord injury, and CCI were identified. Since the assumption was that the medical advancement improved patient survival in general during the last decades, even year of admission was included as covariate in the model. In order to identify a cut-off age where a treatment modality is not associated anymore with greater survival the adjusted HR of a certain age and above was plotted over age with 95% C.I.

Study Type

Observational

Enrollment (Actual)

6231

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

70 years and older (OLDER_ADULT)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

National patient registry extract with patients suffering from C2 fracture

Description

Inclusion Criteria:

  • C2-fracture
  • Age ≥70 years

Exclusion Criteria:

  • no C2-fracture
  • Age <70 years

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Surgical treatment
Patients ≥70 years with C2 fracture coded in patient registry (ICD-10: S12.1) treated with surgical fracture stabilisation
Stabilisation of C2-fracture by posterior fusion C1-C2, posterior fusion C2-C3, anterior fusion C2-C3 (no postoperative collar) or anterior screw osteosynthesis C2 (postoperative collar for 6 weeks).
Non-surgical treatment
Patients ≥70 years with C2 fracture coded in patient registry (ICD-10: S12.1) treated non-surgically
Cervical collar immobilisation for 12 weeks.
Other Names:
  • Conservative treatment

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Survival
Time Frame: Censored observational time (20 years)
Survival as registered in Swedish National Cause of Death Registry
Censored observational time (20 years)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

October 1, 2015

Primary Completion (ACTUAL)

December 1, 2016

Study Completion (ACTUAL)

December 1, 2016

Study Registration Dates

First Submitted

July 18, 2016

First Submitted That Met QC Criteria

July 19, 2016

First Posted (ESTIMATE)

July 20, 2016

Study Record Updates

Last Update Posted (ACTUAL)

May 19, 2017

Last Update Submitted That Met QC Criteria

May 18, 2017

Last Verified

May 1, 2017

More Information

Terms related to this study

Other Study ID Numbers

  • AxisFractureSweden

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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