The evidence-based medicine behind vertebral augmentation: Changing the discussion post-2009

Megan Wood -   Print  |

In 2009, The New England Journal of Medicine published two studies, the INVEST and Australian trials, that cast doubt on the benefits of vertebral augmentation.1,2 The analyses found no significant differences in pain relief between vertebroplasty and a sham intervention. These studies fueled confusion among providers, leaving many in the industry unsure of the potential benefits associated with vertebral augmentation.

This content is sponsored by Medtronic

 

Patients with a VCF have a five-fold increased risk of suffering a subsequent vertebral fracture compared with their pre-morbid condition or age matched controls.3, 4 Each additional VCF increases a patient's mortality risk.5

 

Several recent large clinical studies followed for at least 12 months after vertebral compression fracture (VCF) have concluded that mortality rates following VCFs are significantly higher for patients treated conservatively versus VP or BKP, while other studies have concluded no difference. For more information, visit www.medtronic.com/bkpmortality.

 

Since 2009, six retrospective claims studies have been published, where researchers focused on mortality risk of balloon kyphoplasty and vertebroplasty compared to that of non-surgical management.

 

1. The 2017 Ong et al. analysis investigated if VCF patients were at a higher risk of mortality in the years following the publication of the 2009 trials. The study included more than 2 million patients, broken down as follows: 261,756 BKP patients, 117,232 VP patients and 1,698,956 NSM patients.6 Overall, the propensity-adjusted 10-year mortality risk for the VCF population was 85.1 percent; procedure comparisons at 10-year follow up showed:

 

  • 24 percent higher mortality risk for NSM versus BKP, p<0.001
  • 8 percent higher mortality risk for NSM versus VP, p<0.001
  • 13 percent lower mortality risk for BKP versus VP, p<0.001

 

2. The Edidin et al. 2015 study examined a total of 1,038,956 VCF patients with up to four years follow up. Of the patients, 141,343 patients underwent BKP and 75,364 underwent VP. The non-operated patients had a 55 percent higher propensity-adjusted mortality risk (p<0.001) than the BKP patients and a 25 percent higher mortality risk (p<0.001) than the VP patients. Researchers found the non-operated patients experienced significantly higher adjusted risks of pneumonia, myocardial infarction/cardiac complications, deep vein thrombosis and urinary tract infection than the BKP patients experienced. Also, the non-operated group had lower adjusted risks of subsequent augmentation/fusion, subsequent augmentation and pulmonary/respiratory complications.7

 

3. The 2014 Lange et al. study analyzed 3,607 patients with osteoporotic VCFs, of which 598 underwent BKP or VP with a five-year follow up. Using propensity score matching, researchers found patients in the operated group were 43 percent less likely to die compared to the non-operated cohort (p<0.001). Further, those patients receiving BKP had a 66.7 percent 60-month adjusted survival rate compared to the 58.7 percent survival rate for VP (p=0.68).8

 

4. In 2013, McCullough et al. studied one-year mortality risk among 10,541 augmented patients and 115,851 NSM patients. The study, utilizing a 20 percent sample of Medicare data, found mortality was lower in the augmented group (5.2 percent) than in the control group (6.7 percent) using traditional covariate adjustments (p<0.001). After propensity score matching, accounting for selection bias, however, the researchers found no significant difference between the augmented (5.6 percent) and control patients (5.2 percent) for one-year morality (p=0.18).9

 

5. The 2013 Chen et al. study compared VP, BKP and non-operated management for VCF patients with total follow up of 129,783 person-years. The study involved 68,752 VCF patients broken into the following cohorts: 55.6 percent nonoperative, 11.2 percent VP and 33.2 percent BKP. The study demonstrated kyphoplasty yielded longer three-year patient survival at 59.9 percent compared with VP at 49.7 percent and non-operated treatment at 42.3 percent (p<0.001).10

 

6. The 2011 Edidin A. et al. study analyzed Medicare data from 2005 to 2008 to assess the mortality risk for VCF patients receiving non-operated management, BKP or VP with up to four years follow up. Of the 858,978 total patients newly diagnosed with VCFs, 13.9 percent (119,253 patients) received BKP and 7.4 percent (63,693 patients) received VP. Researchers found adjusted survival rates of 60.8 percent in the operated cohort to be higher compared to 50 percent in the non-operated cohort (p<0.001). In comparing the operated subgroups, survival of 57.3 percent for VP patients, was lower than 62.8 percent for BKP patients (p<0.001).11

 

Despite much clinical evidence supporting vertebral augmentation,12,13 some providers strayed away from the procedures. For example, vertebral augmentation volume fell from 24 percent in 2009 to 14 percent in 2014 (p<0.001), according to the 2017 analysis.6 Payers also harnessed the two 'sham' trials to deny payment for vertebral augmentation. In the U.S., a Medicare contractor published negative coverage, later revising that policy with restrictive requirements.

 

"The 2009 studies caused significant confusion as to the effectiveness of the procedure and what to do with the patient," says Douglas Beall, MD, of Edmond-based Oklahoma Spine Hospital.

 

Josh Hirsch, MD, Boston-based Massachusetts General Hospital's Neuro Interventional Radiology director and the American Society of Spine Radiology's immediate past president, noted, "Trials should inform our decision-making, not make the decision for us. That is the key to patient-centric care."

 

Did the 2009 studies shift VCF treatment patterns?
The most recent of the retrospective claims studies on VCFs and mortality risk, the 2017 Ong KL, et al. analysis is titled, "Were VCF Patients at Higher Risk of Mortality Following the 2009 Publication of the Vertebroplasty 'Sham' Trials?" Medtronic funded the analysis and offered minimal input into the study's design, but did not engage in the data collection, management, analysis or interpretation.

 

Kevin Ong, PhD, PE, principal engineer of Exponent and adjunct member of Drexel University's School of Biomedical Engineering in Philadelphia, served as principal researcher for the Exponent-led study. Drs. Beall, Hirsch and others also served as researchers.

 

"[In addition to other factors,] we wanted to examine whether the publication of the 2009 'sham' control studies resulted in lower use of vertebral augmentation. We found that, in the five-year period following 2009, patients had greater mortality risk for VCF patients," says Dr. Ong.

 

Investigators used Medicare data to examine U.S. vertebral augmentation rates between 2010 and 2014 compared to the previous five-year period. The study examined the difference in mortality and morbidity of VCF patients pre- and post-2009 and compared risks between vertebral augmentation and NSM.

 

In addition to the mortality risk findings listed above, the analysis revealed the following key data points:

 

1. Vertebral augmentation patients accounted for 20 percent of VCF patients in 2005, peaking at 24 percent between 2007 and 2008 before dropping to 14 percent in 2014.

 

2. VCF patients' propensity-adjusted mortalityrisk was 4 percent greater between 2010 and 2014, compared to VCF patients' risk in the 2005 to 2009 time period (p<0.001).

 

3. At one year, cardiac complications and pneumonia were associated with at least 10 percent greater morbidity risk for NSM patients compared to BKP patients. Dr. Ong and his team did not see a higher prevalence of baseline co-morbidities in NSM patients compared to augmentation patients.

 

4. The length of stay for NSM patients clocked in at 0.2 days shorter than the BKP patients. However, about twice as many BKP patients were discharged home.6

 

The following limitations apply to the 2017 study and are generally applicable to the other retrospective claims analyses:

 

  • Retrospective database analyses may be prone to selection bias6-11
  • Confounding by other unmeasured selection bias or variables not considered in the analysis is possible6-11
  • Causality of treatment received with mortality outcomes cannot be demonstrated6-11 nor can causality of the sham trial publications to increased mortality found in the 5-year period following6
  • Cause of death not available in database6-11
  • Was not possible to evaluate all possible comorbidities8,10
  • Outcomes such as pain and quality of life were not available6-11

 

Dr. Hirsch agrees with the conclusion: "We found that there has been an increase in the mortality rate of all VCF patients in the second group [2010 to 2014] compared to the first group [2005 to 2009]."

 

Impact on payers, referrers and providers
The 2017 analysis' findings align with the majorityof the five above studies on mortality and VCF patients published after the 2009 'sham' studies.

 

"[The study] will certainly help strengthen our overall data collectively and protect our positive coverage policies that are in place," says Jeff Cambra, general manager of Medtronic. "This will likely be valuable data, especially for treating and referring physicians."

 

Dr. Hirsch believes this study will provoke a discussion among referring clinicians about the best evidence-based treatment for their patients.

 

"These procedures really do provide meaningful benefits to patients," he says. "I manage many patients with conservative therapy; there's a role for that. What I object to is when patients call their doctors and the doctor says there is nothing to do [for treatment]."

 

About Balloon Kyphoplasty - Indication and Risk Statement
Kyphon™ Balloon Kyphoplasty is a minimally invasive procedure for the treatment of pathological fractures of the vertebral body due to osteoporosis, cancer or benign lesion. The complication rate with Kyphon Balloon Kyphoplasty has been demonstrated to be low. There are risks associated with the procedure (e.g., cement extravasation), including serious complications, and through rare, some of which may be fatal.

 

Risks of acrylic bone cements include cement leakage, which may cause tissue damage, nerve or circulatory problems, and other serious adverse events, such as: Cardiac arrest, Cerebrovascular accident, Myocardial infarction, Pulmonary embolism and Cardiac embolism. For complete information regarding indications for use, contraindications, warnings, precautions, adverse events, and methods of use, please reference the devices' Instructions for Use included with the product.

 

Conclusion
Medtronic is laser-focused on enhancing treatments for patients with VCFs and partners with the National Osteoporosis Foundation and National Bone Health Alliance. The national education outreach partnerships are designed to raise awareness about spine fracture risk and BKP as a treatment alternative among 70,000-plus clinicians and consumers at society meetings and via social media channels.

 

"We are committed to driving innovation, building upon our strong portfolio of clinical data, and educating consumers and clinicians on ways to prevent, diagnose and treat patients with vertebral compression fractures," says Mr. Cambra.

 

Since surgeons performed the first Medtronic Kyphon® Balloon Kyphoplasty procedures in 1998, it has been used to treat more than 1 million fractures.

 

Drs. Ong, Beall and Hirsch are hopeful the new analyses will shed light on the implications of VCF treatment patterns and add to the conversation.

 

"These findings give a real insight in the implications of the shifting in treatment patterns," concludes Dr. Ong. "I think our study will add to the debate about whether VCF patients should be treated with augmentation."

 

References
1Kallmes D, et. al, A Randomized Trial of Vertebroplasty for Osteoporotic Spinal Fractures. The New England Journal of Medicine. 2009 Aug. DOI: 10.1056/NEJMoa0900563.
2Buchbinder R, et. al, A Randomized Trial of Vertebroplastyfor Painful Osteoporotic Vertebral Fractures. The New England Journal of Medicine. 2009 Aug. DOI: 10.1056/ NEJMoa0900429.
3Lindsay R, et al., Risk of new vertebral fracture in the year following a fracture. JAMA. 2001; 285(3):320-33
4Ross P, et al., Pre-Existing Fractures and Bone Mass Predict Vertebral Fracture Incidence in Women. Ann Intern Med. 1991; 114(11):919-923.
5Kado DM, et al. (1999) Arch Intern Med 159:1215
6Ong KL, Beall DP, Frohbergh M, Lau E, Hirsch JA. Were VCF patients at higher risk of mortality following the 2009 publication of the vertebroplasty "sham" trials? Osteoporosis International 2017 Oct 24. doi: 10.1007/s00198-017-4281-z. PubMed PMID: 29063215.
7Edidin AA, Ong KL, Lau E, Kurtz SM. Morbidity and Mortality after Vertebral Fractures: Comparison of Vertebral Augmentation and Non-Operative Management in the Medicare Population. Spine (Phila Pa 1976). 2015 Aug 1;40(15):1228-41. doi: 10.1097. PubMed PMID: 26020845.
8Lange A, Kasperk C, Alvares L, Sauermann S, Braun S. Survival and cost comparison of kyphoplasty and percutaneous vertebroplasty using German claims data. Spine (Phila Pa 1976). 2014 Feb 15;39(4): 318-26. doi: 10.1097/ BRS.0000000000000135. PubMed PMID:  4299715.
9McCullough BJ, Comstock BA, Deyo RA, Kreuter W, Jarvik JG. Major medical outcomes with spinal augmentation vs conservative therapy. JAMA Intern Med. 2013 Sep 9;173(16):1514-21. doi: 10.1001/jamainternmed.2013.8725. PubMed PMID: 23836009; PubMed Central PMCID: PMC4023124.
10Chen A, et. al, Impact of Nonoperative Treatment, Vertebroplasty, and Kyphoplasty on Survival and Morbidity After Vertebral Compression Fracture in the Medicare Population. J Bone & Joint Surgery, 2013.
11Edidin AA, Ong KL, Lau E, Kurtz SM. Mortality risk for operated and nonoperated vertebral fracture patients in the medicare population. J Bone Miner Res. 2011 Jul;26(7):1617-26. doi: 10.1002/jbmr.353.
12Wardlaw D, et al., Efficacy and safety of balloon kyphoplasty compared with non-surgical care for vertebral compression fracture (FREE): a randomised controlled trial. The Lancet. 2009 Feb. DOI: 10.1016/S0140-6736(09)60010-6.
13Klazen CA, et al. Clinical course of pain in acute osteoporotic vertebral compression fractures. Journal of Vascular and Interventional Radiology. 2010 Sept. DOI: 10.1016/j.jvir.2010.05.018.

 

 

PMD020431-1.0

 

UC201806890 EN

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Kyphon™ Balloon Kyphoplasty incorporates technology developed by Gary K. Michelson, M.D.

 

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