Research Review By Dr. Michael Haneline©


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Date Posted:

April 2022

Review Title:

Spinal Manipulation Reduces Escalation of Care & Risk of Adverse Drug Events for Older Chronic LBP Patients

Studies Reviewed:

  1. Whedon J, Kizhakkeveettil A, Toler A, et al. Initial Choice of Spinal Manipulation Reduces Escalation of Care for Chronic Low Back Pain Among Older Medicare Beneficiaries. Spine 2022; 47(4): E142-E148.
  2. Whedon J, Kizhakkeveettil A, Toler A, et al. Initial Choice of Spinal Manipulative Therapy for Treatment of Chronic Low Back Pain Leads to Reduced Long-term Risk of Adverse Drug Events Among Older Medicare Beneficiaries. Spine 2021; 46(24): 1714-1720.

Author's Affiliations:

Southern California University of Health Sciences, Whittier, CA and Geisel School of Medicine at Dartmouth, Hanover, NH, USA.

Background Information:

Because of their similarities, this Research Review combines 2 recent studies that were done by the same author group, which investigated long-term outcomes of older Medicare recipients with chronic low back pain (cLBP) who received Opioid Analgesic Therapy (OAT) or Spinal Manipulative Therapy (SMT). One study focused on the escalation of patient care and the other on the risk of adverse drug events (ADEs).

Chronic low back pain (cLBP) has been shown to affect 70% to 85% of the elderly population at least once in their lifetime, with 90% of those afflicted having more than one episode (1). LBP can be disabling, limiting an older person’s ability to perform common everyday tasks, many of which are required to support independent living as we age!

There has been a dramatic increase in treatment costs for LBP among Medicare beneficiaries, although such increases have not correlated with improved outcomes (2). Furthermore, little evidence supports the use of many invasive and expensive spine care procedures. The use of OAT for cLBP patients is still common, even though its long-term safety is unknown, and overprescribing is thought to be the leading cause of the opioid crisis in the USA (3). The risks of opioid medications are amplified and potentially worse in older patients!

Both pharmacological and nonpharmacological approaches to the management of cLBP are included in clinical guidelines, though it is uncertain how utilization of OAT affects the escalation of care of cLBP patients as compared with SMT. Treatment escalation (or, escalation of care) refers to additional, more complex health care interactions or interventions being required, including hospitalizations, emergency department visits, advanced diagnostic imaging, specialist visits, lumbosacral surgery, interventional pain medicine techniques, and encounters for potential complications of cLBP. Previous studies have reported that use of chiropractic care for patients with LBP is associated with decreased opioid use and reduced risk of ADEs. However, the efficiency and value of long-term care of cLBP for either OAT or SMT are uncertain.

The objectives of these studies were:
  1. to compare long-term outcomes for SMT and OAT concerning escalation of care for patients with cLBP, and
  2. to compare SMT and OAT to determine their impact on the risk of ADEs among older adults receiving long-term care for cLBP.

Pertinent Results:

The same 28 160 patient records were used in both studies. The SMT cohort was comprised of 4998 patients (18%), OAT cohort was 20 947 (74%), crossover cohort SMTX 1431 (5%), and crossover cohort OATX 784 (3%). There were 6429 patients in the combined cohort SMTC (initially treated with SMT and received a combination of SMT and OAT) and 21 731 patients in combined cohort OATC (initially treated with OAT and received a combination of SMT and OAT).

The ratio of females to males was approximately 3:1 within all cohorts. There were approximately 5 times as many patients with lower socioeconomic status among patients who received only OAT, as compared with those who received only SMT.

Patients who received only OAT had higher comorbidity scores and were more frequently diagnosed with depression and osteoarthritis of the hip or knee than those who received only SMT. Most cases of LBP in these studies were classified as nonspecific LBP. However, more patients who received only OAT were diagnosed with radiculopathy, spinal stenosis, herniated disc and spondylolisthesis, as compared with those who received only SMT (overall, those who received only OAT were more complex cases from a clinical perspective).

Escalation of Care Study Results:
  • Escalated care encounters occurred more frequently when patients received OAT as their initial approach to care, occurring in both the OAT and OATC (combination of opioids first, then SMT) cohorts. For example, the hospitalization rate for SMT was 0.8% versus 4.9% for OAT, advanced diagnostic imaging occurred in 14.8% of SMT patients versus 45.0% of those who received OAT, and emergency department visits were 4.6% for SMT versus 22.9% for OAT.
  • However, in the presence of spinal injury, escalated care encounters were more than 50% higher among patients who received SMT as their initial approach to care.
  • The adjusted rate of any escalated care encounter was 2.43 to 2.67 times higher for cohort OATC versus cohort SMTC (SMT first, then opioids).
Adverse Drug Events Study Results:
  • 18.3% of patients who received OAT for long-term care of cLBP experienced an ADE, as compared to less than 1% of patients who received SMT.
  • More than twice as many patients who crossed over from SMT to OAT had an ADE as compared with those who crossed over from OAT to SMT.
  • The frequency of ADEs in the OATC cohort was also higher in every ADE category than in the SMTC cohort. (i.e. opioids first is associated with more ADEs versus SMT first, even when opioids are then added!).
  • 14.3% patients who received OAT for long-term care experienced opioid dependence or abuse as compared to only 0.3% of patients who received SMT.
  • 17.8% of older Medicare beneficiaries who initiated care with OAT experienced an outpatient ADE, as compared to 3% of those who initially chose SMT.
  • After controlling for patient characteristics, health status and propensity score, the adjusted rate of ADE was more than 42 times higher for initial choice of OAT versus initial choice of SMT.

Clinical Application & Conclusions:

The adjusted rate of escalated care encounters for older Medicare beneficiaries who initiated long-term care for cLBP with OAT was significantly higher than those who initiated care with SMT. This is an important and impactful finding!

The adjusted rate of ADEs for older Medicare beneficiaries who received long-term care for cLBP and who initially chose OAT was also substantially higher than those who initially chose SMT. Another important and impactful finding!

These studies provide evidence for clinicians that, at least in older patients, initial treatment with SMT (as compared with OAT) for the long-term care of cLBP reduces the likelihood that a patient will experience escalated care or ADE. The results of these studies, and others, could and should have huge implications for both patient safety and healthcare costs! Conservative care for cLBP should be a first line approach!

Study Methods:

Both studies retrospectively analyzed data representing Medicare fee-for-service claims data spanning the 5-year period from 2012 through 2016. The data were analyzed looking for differences in outcomes between the following cohorts:
  1. those treated with long-term opioid analgesic therapy (OAT),
  2. those treated with long-term spinal manipulative therapy (SMT),
  3. those initially treated with OAT followed by long-term SMT (OATX),
  4. those initially treated with SMT followed by long-term OAT (SMTX),
  5. those initially treated with OAT and received a combination of SMT and OAT (OATC), and
  6. those initially treated with SMT and received a combination of SMT and OAT (SMTC).
The studies’ cohorts were comprised of patients who received long-term management of cLBP with SMT or OAT and were 65 to 84 years-of-age. Long-term management for OAT was defined as 6 or more standard 30-day supply prescription fills in a 12-month period and for SMT was defined as 12 office visits that included spinal manipulation for LBP in any 12-month period with at least one visit per month.

In addition to collecting data on patients’ demographics, the health status of included patients were collected by way of Charlson comorbidity scores, the presence of comorbid chronic conditions (osteoarthritis of the hip or knee), as well as fibromyalgia and depressive disorder. LBP was categorized as nonspecific LBP, radiculopathy, herniated disc, spondylolisthesis, sprain/strain, or spinal stenosis.

The following variables were controlled for in the statistical analysis: age, sex, race, beneficiary residence ZIP code, Part D low-income subsidy, dual eligibility status, diagnostic category, chronic condition, and Charlson comorbidity score. Selection bias was accounted for by modeling of the outcome by covariates and propensity scoring by binning. Potential complications of cLBP and spinal injuries, which may rarely occur as a complication of SMT of the lower back, were taken into consideration.

Study Strengths / Weaknesses

Both papers were conducted via a well-done retrospective analysis of health claims data which employed elegant statistical analysis procedures.

To further strengthen the findings of the ADE study, a previous report on adults with LBP was consistent, finding that the adjusted likelihood of an ADE occurring in an outpatient setting within 12 months was 51% lower among those who received chiropractic services as compared those who did not (4).

Similarly, the strength of the escalation of care study is bolstered by similar findings by other researchers. For instance, Davis et al. (5) reported that there was a significant decrease in spending on spinal imaging and testing when Medicare beneficiaries had increased access to chiropractic care. Also, Chenot et al. (6) found that there was an increased use of imaging and therapeutic interventions when patients consulted a specialist for LBP.

Following is a list of limitations that are associated with the use of health claims data for research:
  1. Inconsistencies in billing practices and coding of procedures and diagnoses. For example, common CPT codes were used to identify procedures, such as spinal manipulation, although some clinicians may use other procedure codes.
  2. There was a lack of an indication of pain severity, and lack of diagnoses in pharmacy claims data, preventing the researchers from controlling for exposures and the assessment of outcomes.
  3. The potential for confounding by indication in which patients with worse outcomes may have had higher rates of escalation of care that led to their choice of treatment in the first place. This limitation was controlled for by factoring in comorbid chronic conditions and depressive disorder.
  4. Selection bias, which the authors addressed by utilizing vigorous approaches to propensity scoring that were meant to minimize the risk of selection bias.
  5. The presence of confounders, which are factors that are not part of a study but may affect its administration and results.

Additional References:

  1. de Souza I, Sakaguchi T, Yuan S, et al. Prevalence of low back pain in the elderly population: a systematic review. Clinics (Sao Paulo) 2019; 74: e789; 10.6061/clinics/2019/e789.
  2. Deyo R, Mirza S, Turner J, et al. Overtreating chronic back pain: time to back off?. J Am Board Fam Med 2009; 22: 62–8.
  3. Foster N, Anema J, Cherkin D, et al. Prevention and treatment of low back pain: evidence, challenges, and promising directions. Lancet 2018; 391: 2368–83.
  4. Whedon J, Toler A, Kazal L, et al. Impact of chiropractic care on use of prescription opioids in patients with spinal pain. Pain Med 2020; 21: 3567–73.
  5. Davis M, Yakusheva O, Liu H, et al. Access to chiropractic care and the cost of spine conditions among older adults. Am J Manag Care 2019; 25: e230–6.
  6. Chenot J, Leonhardt C, Keller S, et al. The impact of specialist care for low back pain on health service utilization in primary care patients: a prospective cohort study. Eur J Pain 2008; 12: 275–83.

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