Adding chiropractic care to standard medical management of low back pain (LBP) in a military population reduced patient-reported pain and disability and improved satisfaction scores compared with standard treatment alone, new data show.
The findings, reported by Christine M. Goertz, DC, PhD, from Palmer College of Chiropractic, Davenport, Iowa, and colleagues in an article published online May 18 in JAMA Network Open, confirm results from the team’s pilot study.
In addition, the new data align with recent guidelines from the American College of Physicians that recommend inclusion of spinal manipulation, among other nondrug treatments, as first-line therapy for acute and chronic low-back pain.
Patients were screened between September 28, 2012, and November 20, 2015, and 250 patients from each of the study sites were allocated to receive usual medical care with chiropractic care (375 participants) or usual medical care alone (375 participants). Usual medical care was defined as any care recommended or prescribed by nonchiropractic military clinicians to treat LBP, including self-management advice, drug treatment, physical therapy, or referral to a pain clinic.
Patients in the chiropractic care group received standard treatment plus up to 12 chiropractic visits for spinal manipulative therapy in the low back and adjacent regions during the 6-week intervention period. Additional therapies, such as rehabilitative exercise, interferential current therapy, ultrasound therapy, cryotherapy, superficial heat, and other manual therapies, could also be included in chiropractic care.
The primary outcomes of self-reported pain intensity, as measured by the Numerical Rating Scale, and disability, based on the Roland Morris Disability Questionnaire, both favored usual and chiropractic care compared with usual care alone. At week 6, the mean difference in low-back pain intensity between the combined treatment group and the usual care alone group was −1.1 (95% confidence interval [CI], −1.4 to −0.7), and the mean difference in disability for the respective groups was −2.2 (95% CI, −3.1 to −1.2). Similar findings, although of lesser magnitude, were observed at week 12, they note.
Sensitivity analyses designed to examine possible effects of missing data on results of the primary outcomes showed effects in the same direction, with similar magnitudes and statistical significance.
Moreover, a secondary responder analysis comparing the percentage of patients with at least 30% improvement from baseline at each end point produced relative risks (RRs) favoring a greater benefit for the combined treatment at week 6 (LBP intensity: RR, 1.43 [95% CI, 1.23-1.68]; disability: RR, 1.35 [95% CI, 1.16-1.56]) and week 12 (LBP intensity: RR, 1.43 [95% CI, 1.23-1.68]; disability: RR, 1.26 [95% CI, 1.11-1.43]) in the population overall.
Some differences in RRs observed by treatment site might be explained by variations in the additional interventions, such as electric muscle stimulation and heat or cold therapy, at each site, the authors note. “Chiropractic care consisted of several therapeutic procedures in addition to spinal manipulation. Use of these therapies varied substantially by site.”
The analyses of secondary outcomes showed that overall, at weeks 6 and 12, participants in the combined treatment group reported significantly lower mean worst pain intensity within the last 24 hours (week 6: mean difference, −1.2; [95% CI, −1.6 to −0.8]; week 12: mean difference, −1.1 [95% CI, −1.6 to −0.7]) and symptom bothersomeness (week 6: mean difference, −0.4 [95% CI, −0.6 to −0.2]; week 12: mean difference, −0.4 [95% CI, −0.6 to −0.2]).
Further, patients receiving combined care had significantly better global perceived improvement at 6 weeks at all sites (odds ratio [OR], 0.18; 95% CI, 0.13-0.25), significantly greater mean satisfaction with care at 6 weeks at all sites (mean difference, 2.5; 95% CI, 2.1-2.8), and significantly less pain medication use at week 6 (OR, 0.73; 95% CI, 0.54-0.97) and week 12 (OR, 0.76; 95% CI, 0.58-1.00).
Chiropractic-related adverse events included muscle or joint stiffness, but no serious treatment-related adverse events were reported, the authors report.
“The changes in patient-reported pain intensity and disability as well as satisfaction with care and low risk of harms favoring [usual medical care] with chiropractic care found in this pragmatic clinical trial are consistent with the existing literature on spinal manipulative therapy in both military and civilian populations,” the authors write. “The magnitude of mean between-group differences for both pain…and disability…are consistent with a moderate magnitude of effect as classified by the American College of Physicians and American Pain Society guidelines.”
Although limited by the nonspecific nature of LBP and treatment variations across care sites, “[t]his trial provides additional support for the inclusion of chiropractic care as a component of multidisciplinary health care for LBP, as currently recommended in existing guidelines,” the authors write. They note that further research is needed to understand longer-term outcomes and to assess how differences among patients and interventions influence outcomes.
In an accompanying editorial, Daniel C. Cherkin, MA, PhD, from Kaiser Permanente Washington Health Research Institute in Seattle, Washington, suggests that the findings are “unlikely to be spurious,” given the trial’s large sample size, approximately 90% follow-up rates, and strong analytic methods.
“This trial represents an important contribution to our minimal knowledge of the potential of chiropractic care to improve outcomes of care in military populations,” he writes. “These findings are particularly noteworthy because it is usually more difficult to detect meaningful treatment benefits in patient populations who have especially promising natural histories as they are young, physically fit, and unlikely to be using opioids (<6% of patients) and include a large fraction of patients with acute pain.”
Cherkin cautions that the study‘s strengths should be balanced by its main limitations, which include its nonrandomized design, the lack of a measure of longer-term outcomes, problems with adherence to both treatments at one of the care sites that recruited patients via advertisement vs clinician referral, inability to determine how to explain the observed benefits in the chiropractic group, and the absence of cost-effectiveness data.
He suggests several explanations for the improved outcomes associated with chiropractic care in this study, including the fact that the chiropractic care often included treatments not included in usual medical care, such as electric muscle stimulation and heat or cold therapy, and that patients reported having higher expectations of the combined treatment over usual care. “Furthermore, it appears that patients in the group receiving [usual care] plus chiropractic care may have made more total visits than those in the group receiving [usual care] alone,” he writes.
Even so, the apparent advantages of chiropractic care in the management of LBP warrants additional study, Cherkin writes. “Future evaluations of incorporating chiropractic care into the military health care system should measure longer-term outcomes, estimate its cost-effectiveness, and consider alternative and potentially more efficient implementation strategies,” he states.
In addition, although it may be more complex than adding chiropractic to usual care, “true integration of chiropractic care into the military health care system involving professional communication and referrals between chiropractors and medical personnel has the potential for more effectively and efficiently serving patients and for providing models for other integrated health care systems in civilian settings to follow.”
The study authors disclosed financial relationships with Spine IQ, the American Chiropractic Association, Prezacor Inc, the NCMIC Foundation, RAND Corporation, the US Army Medical Research Acquisition Agency, and Samueli Institute. Cherkin has disclosed no relevant financial relationships.
JAMA Network Open. 2018;1(1):e180105.