J Manipulative Physiol Ther. 2002 (Jan); 25 (1): 1020 ~ FULL TEXT
Ruth P. Hertzman-Miller, MD, MPH, Hal Morgenstern, PhD, Eric L. Hurwitz, DC, PhD,
Fei Yu, PhD, Alan H. Adams, DC, MS, Philip Harber, MD, MPH, and Gerald F. Kominski, PhD
UCLA School of Public Health,
Department of Epidemiology,
Los Angeles, Calif. 90095-1772, USA.
BACKGROUND: Although chiropractors often use physical modalities with spinal manipulation, evidence that modalities yield additional benefits over spinal manipulation alone is lacking.
OBJECTIVE: The purpose of the study was to estimate the net effect of physical modalities on low back pain (LBP) outcomes among chiropractic patients in a managed-care setting.
METHODS: Fifty percent of the 681 patients participating in a clinical trial of LBP treatment strategies were randomized to chiropractic care with physical modalities (n = 172) or without physical modalities (n = 169). Subjects were followed for 6 months with assessments at 2, 4, and 6 weeks and at 6 months. The primary outcome variables were average and most severe LBP intensity in the past week, assessed with numerical rating scales (0-10), and low back-related disability, assessed with the 24-item Roland-Morris Disability Questionnaire.
RESULTS: Almost 60% of the subjects had baseline LBP episodes of more than 3 months' duration. The 6-month follow-up was 96%. The adjusted mean differences between groups in improvements in average and most severe pain and disability were clinically insignificant at all follow-up assessments. Clinically relevant improvements in average pain and disability were more likely in the modalities group at 2 and 6 weeks, but this apparent advantage disappeared at 6 months. Perceived treatment effectiveness was greater in the modalities group.
CONCLUSIONS: Physical modalities used by chiropractors in this managed-care organization did not appear to be effective in the treatment of patients with LBP, although a small short-term benefit for some patients cannot be ruled out.
Keywords: Low Back Pain, Chiropractic, Physical Therapy, Randomized Controlled Trial, Managed Care
From the Full-Text Article:
Low back pain (LBP) is the most common reason for initiating chiropractic care,  and chiropractic is the unconventional or alternative therapy used most often for back pain in the United States. [2, 3] In fact, most visits for LBP are to chiropractors,  and because managed care predominates in many parts of the United States,  these visits are increasingly in managed-care settings. Back-related health care expenditures have been rising dramatically, primarily the result of escalating costs associated with disabling LBP.  Back pain is also a leading cause of lost work days, resulting in almost $9 billion in work-related low-back claims and billions of dollars in additional indirect costs. [7, 8]
Low back pain is treated with a variety of therapies by a number of different health care providers. [9, 10] Physical modalities, such as heat therapy, ultrasound, and electrical muscle stimulation (EMS) are specific treatments that many chiropractors commonly use in conjunction with spinal manipulation. [11, 12] Although there is little evidence that physical modalities alone are effective therapies for LBP, [13, 14] there have been no published studies, to our knowledge, that address the relative benefit of modalities applied to patients with LBP who are receiving chiropractic care.
The purpose of the study was to estimate the net effect of physical modalities used at the discretion of chiropractors in managed care.
The effectiveness of physical modalities among patients with LBP randomized to chiropractic care was assessed in a managed-care practice setting. During 6 months of follow-up in this population of patients with primarily subacute and chronic pain, chiropractic care with or without physical modalities yielded mostly similar pain and disability outcomes. Most patients in both treatment groups had clinically meaningful reductions in pain severity and disability, although the majority of subjects reported at least some pain and impaired function from back pain at 6 months. These findings add to the evidence showing that physical modalities provide, at best, minimal short-term benefit for patients with LBP who are receiving chiropractic care. Specific agents or modalities might, however, be effective in certain patients or in other settings.
Satisfaction with chiropractic care was equally high in both treatment groups, yet patients assigned to receive modalities were more likely to strongly agree that the treatment they received was effective and more likely to seek similar care for future back pain episodes. Because patients were not blinded, these findings illustrating greater perceived benefit do not necessarily reflect greater clinical benefit. For example, patients may simply equate the applications of additional treatments (eg, ultrasound, EMS) as better care regardless of their therapeutic value. Alternatively, modalities may offer patients transient symptomatic relief or improvements in other unmeasured health outcomes that we failed to consider. As a discrete therapy, spinal manipulation as routinely used by chiropractors in the United States and elsewhere has been shown to be beneficial for patients with acute LBP, at least in the short term, [9, 31] and may be an effective treatment for chronic pain.  Current evidence does not support the use of EMS, ultrasound, and other passive modalities for acute or chronic LBP. [9, 31, 32] Exercise and other active physical therapeutic interventions may be of some benefit. [9, 10, 14] Harm resulting from spinal manipulation or physical modalities for LBP is remote. [9, 31, 32]
We are unaware of other randomized clinical trials (RCTs) that have compared chiropractic with and without physical modalities, although 4 RCTs comparing chiropractic care with physical therapy for LBP have been published. Outcomes from chiropractic and hospital outpatient (physiotherapy) care were clinically similar in the Meade et al trial, [33, 34] yet chiropractic patients reported greater satisfaction. Postacchini et al35 and Skargren et al [36, 37] also found little difference between outcomes from chiropractic and physical therapy at 6 or 12 months, although chiropractic patients expectations were more likely to have been fulfilled in the latter trial. During 2 years follow-up of patients randomized to chiropractic or McKenzie physical therapy,  satisfaction and pain and disability outcomes were similar.
The findings from prior studies are consistent with our results showing the ineffectiveness of physical modalities. [9, 10, 14] Active rather than passive interventions, however, may be of benefit for some patients with subacute and chronic LBP. Supervised exercise classes were found to be more effective than primary medical care for patients with subacute LBP after 6 and 12 months,  and supervised exercise interventions led to greater reductions in pain, disability, and costs than self exercise among patients with chronic pain after 12 months.  The value of supervised exercise (vs self exercise) for patients with chronic LBP is also supported by another recent trial that followed patients for 2 years.  However, the authors of an RCT that compared low-impact aerobics with active physical therapy and muscle reconditioning among patients with chronic LBP found equivalent pain and disability outcomes with much less cost in the aerobics group after 6 months. 
The major limitation of our study is its potential lack of generalizability to other practice settings and patient populations. Given that the trial was conducted within 1 managed-care organization, extrapolating our findings to patients with LBP in other settings may be inappropriate. Patients under other reimbursement models, such as fee-for-service, workers compensation, and third party liability, may differ in ways that affect treatment outcomes. In addition, chiropractors practicing in other environments may differ in their relations with patients, manipulative techniques, the frequency and duration of visits, the length and intensity of LBP care, and in their overall approach to patients. Findings from a recent study of chiropractic utilization in North America, for example, documented wide geographic variation in the frequency of visits during episodes of back-pain care.1 Despite possible differences, other ambulatory LBP patient populations are similar to ours in terms of back-pain severity [38, 43, 44] and disability, [15, 43, 4547] and most chiropractors in the United States are taught and use the same general types of spinal manipulation used by the chiropractors at our study site. [11, 12]
Physical modalities used at the discretion of chiropractors in this managed-care setting do not appear to be more effective than chiropractic care without modalities in the treatment of patients with LBP, although a small short-term benefit for some patients cannot be ruled out. Given the added expense of office-based modalities, chiropractors may deliver equally effective and more cost-effective care by withholding modalities, educating patients, and perhaps recommending at-home applications of agents for the temporary relief of symptoms. However, the discrepancy between effects on pain and disability outcomes and perceptions of treatment effectiveness suggests that modalities may enhance the real or perceived effectiveness of chiropractic care among some patients. The perceptions of patients with LBP regarding treatment effectiveness and how these perceptions relate to clinical outcomes and costs and to preferences for subsequent care should be investigated in future studies.
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