Impact of sham-controlled vertebroplasty trials on referral patterns at two academic medical centers

Were VCF patients at higher risk of mortality following the 2009 publication of the vertebroplasty "sham" trials?

The 5-year period following 2009 saw a steep reduction in vertebral augmentation volume and was associated with elevated mortality risk in vertebral compression fracture (VCF) patients. The risk of mortality following a VCF diagnosis was 85.1% at 10 years and was found to be lower for balloon kyphoplasty (BKP) and vertebroplasty (VP) patients.

INTRODUCTION

BKP and VP are associated with lower mortality risks than non-surgical management (NSM) of VCF. VP versus sham trials published in 2009 sparked controversy over its effectiveness, leading to diminished referral volumes. We hypothesized that lower BKP/VP utilization would lead to a greater mortality risk for VCF patients.

METHODS

BKP/VP utilization was evaluated for VCF patients in the 100% US Medicare data set (2005-2014). Survival and morbidity were analyzed by the Kaplan-Meier method and compared between NSM, BKP, and VP using Cox regression with adjustment by propensity score and various factors.

RESULTS

The cohort included 261,756 BKP (12.6%) and 117,232 VP (5.6%) patients, comprising 20% of the VCF patient population in 2005, peaking at 24% in 2007-2008, and declining to 14% in 2014. The propensity-adjusted mortality risk for VCF patients was 4% (95% CI, 3-4%; p < 0.001) greater in 2010-2014 versus 2005-2009. The 10-year risk of mortality for the overall cohort was 85.1%. BKP and VP cohorts had a 19% (95% CI, 19-19%; p < 0.001) and 7% (95% CI, 7-8%; p < 0.001) lower propensity-adjusted 10-year mortality risk than the NSM cohort, respectively. The BKP cohort had a 13% (95% CI, 12-13%; p < 0.001) lower propensity-adjusted 10-year mortality risk than the VP cohort.

CONCLUSIONS

Changes in treatment patterns following the 2009 VP publications led to fewer augmentation procedures. In turn, the 5-year period following 2009 was associated with elevated mortality risk in VCF patients. This provides insight into the implications of treatment pattern changes and associated mortality risks.

Trends in Inpatient Vertebroplasty and Kyphoplasty Volume in the United States, 2005-2011: Assessing the Impact of Randomized Controlled Trials

STUDY DESIGN

Retrospective analysis of the Nationwide Inpatient Sample, 2005-2011.

OBJECTIVE

To identify trends in procedural volume and rates in the time period surrounding publication of randomized controlled trials (RCTs) that examined the utility of vertebroplasty and kyphoplasty.

SUMMARY OF BACKGROUND DATA

Vertebroplasty and kyphoplasty are frequently performed for vertebral compression fractures. Several RCTs have been published with conflicting outcomes regarding pain and quality of life compared with nonsurgical management and sham procedures. Four RCTs with discordant results were published in 2009.

MATERIALS AND METHODS

The Nationwide Inpatient Sample provided longitudinal, retrospective data on United States' inpatients between 2005 and 2011. Inclusion was determined by a principal or secondary International Classification of Diseases, Ninth Revision, Clinical Modification code of 81.65 (percutaneous vertebroplasty) or 81.66 (percutaneous vertebral augmentation; "kyphoplasty"). No diagnoses were excluded. Years were stratified as "pre" (2005-2008) and "post" (2010-2011) in relation to the 4 RCTs published in 2009. Patient, hospital, and admission characteristics were compared using Pearson χ test.

RESULTS

The estimated annual inpatient procedures performed decreased from 54,833 to 39,832 in the pre and post periods, respectively. The procedural rate for fractures decreased from 20.1% to 14.7% (P<0.0001). Patient and hospital demographics did not change considerably between the time periods. In the post period, weekend admissions increased (34.2% vs. 12.4%, P<0.0001), elective admissions decreased (21.4% vs. 40.0%, P<0.0001), routine discharge decreased (33.0% vs. 52.1%, P<0.0001), and encounters with ≥3 Elixhauser comorbidities increased (54.5% vs. 39.1%, P<0.0001).

CONCLUSIONS

The absolute rate of inpatient vertebroplasty and kyphoplasty procedures for fractures decreased 5% in the period (2010-2011) following the publication of 4 RCTs in 2009. The proportion of elective admissions and routine discharges decreased, possibly indicating a population with greater disease severity. Although our analysis cannot demonstrate a cause-and-effect relationship, the decreased inpatient volume and procedural rates surrounding the publication of sentinel negative RCTs is clearly observed.