J Manipulative Physiol Ther 2000 (May); 23 (4): 239–245 ~ FULL TEXT
Joanne Nyiendo, PhD, Mitchell Haas, DC, Peter Goodwin, MD
Western States Chiropractic College,
Portland, OR 97230, USA.
Patients with chronic (>6 weeks), recurrent lower back pain were treated by either a chiropractor or a family medicine clinic. After one month of treatment, chiropractic patients averaged higher improvement across all outcome measurements. The differences between provider groups were most marked for the question involving satisfaction with overall care (chiropractic-90%; medical–52%). Chiropractic patients also reported greater improvement in pain severity and functional disability. This study concluded that chiropractic patients expressed greater satisfaction regarding information and treatment provided.
BACKGROUND: Chronic low-back pain is a significant public health problem for which few therapies are supported by predictable outcomes. In this report, practice activities and 1-month outcomes data are presented for 93 chiropractic patients and 45 medical patients with chronic, recurrent low-back pain.
DESIGN: A prospective, observational, community-based feasibility study involving chiropractors and family medicine physicians.
SETTING: Forty private chiropractic clinics, the outpatient clinic of the Department of Family Medicine at Oregon Health Sciences University, and 5 other Portland area family medicine clinics. Outcomes Measures: The main outcome measures were pain severity, functional disability, sensory and affective pain quality at 1 month, and patient satisfaction assessed at 7 to 10 days and at 1 month.
RESULTS: Although differences were noted in age, sex, education, and employment, the patients were closely matched at baseline with respect to frequency, severity, and type of low-back pain and the psychosocial dimensions of general health. The treatment of choice for chiropractors was spinal manipulation and physical therapy modalities; for medical physicians antiinflammatory agents were most frequently used. Chiropractic patients averaged 4 visits, and medical patients averaged 1 visit. On average, chiropractic patients showed improvement across all outcomes: 31% change in pain severity, 29% in functional disability, 36% in sensory pain quality, and 57% in affective pain quality. Medical patients showed minimal improvement in pain severity (6%) and functional disability (1%) and showed deterioration in the sensory (29%) and affective (26%) dimensions of pain quality. Satisfaction scores were higher for chiropractic patients. Outcomes for medical patients were heavily dependent on psychosocial status at baseline.
CONCLUSION: Patients with chronic low-back pain treated by chiropractors show greater improvement and satisfaction at 1 month than patients treated by family physicians. Nonclinical factors may play an important role in patient progress. Findings from the Health Resources and Services Administration-funded project will include a report on the influence of practice activities, including more frequent visits by chiropractic patients, on the clinical course of low-back pain and patient outcomes.
From the FULL TEXT Article:
A variety of procedures are available to treat low-back pain, but, with few exceptions, it is not known which patients are likely to benefit from which treatment and under which circumstances. For chronic low-back conditions, there is little consensus regarding the most appropriate method of treatment. Patients may be receiving less than optimal care. The current climate of health care reform, with its emphasis on patient outcomes and physician accountability, provides a unique opportunity for practice-based researchers. This study is important because it represents an effort by chiropractors and family medicine physicians to systematically measure patient outcomes. The preliminary data obtained on patient characteristics, practice patterns, and patient outcomes revealed some findings of interest that suggest directions for hypothesis development and future research.
The 2 patient cohorts presented some sociodemographic differences (age, sex, education, employment). At baseline, patients of family practice physicians scored more poorly with respect to overall health status and ability to perform the usual tasks of daily living (eg, walking, climbing stairs, lifting). They also reported slightly more bodily pain. These findings may be a consequence of the 8-year mean age difference between the cohorts. The effect of these potential confounders on outcomes is being explored in the longterm study.
Although research published in both the chiropractic and medical literature has repeatedly shown radiographic findings to be poorly correlated with low-back pain, [22-26] in this study of chronic low-back pain, 1 in 4 patients underwent radiography. The duration of the problem beyond 1 month, [27-28] coupled with physician uncertainty,  may have influenced the decision to obtain radiographic films, a decision made with nearly equal frequency by the 2 physician types.
The therapy of choice for participating family physicians was antiinflammatory drugs (eg, ibuprofen). The findings from the first study were consistent with the literature that describes medical treatments as typically including drugs, physical therapy, bed rest, and exercise regimens.  Ninety-six percent of chiropractic patients received spinal manipulative therapy. The greater use of full-spine adjustment may be a consequence of chiropractors' view of the spine and locomotor system as an integrated unit. As low-back pain becomes chronic, local problems may cause adaptations and compensation, which potentially lead to secondary problems in other regions of the spine.  The extensive use of ancillary procedures is consistent with the literature that reports that physical therapy modalities and exercise regimens are an integral part of the therapeutic approach for many chiropractors. [32-35]
Unlike drugs prescribed by medical physicians, spinal manipulation could not be selfadministered by patients. Thus the number of physician visits by chiropractic patients was necessarily greater than the number recorded for medical patients. The effect of those more frequent visits on patient outcomes will be evaluated in the long-term study.
One possible explanation for the greater improvement seen in the chiropractic cohort may be the efficacy of spinal manipulation or some combination of manipulation and other modalities. Although there is ample evidence in the literature to support a specific benefit from manipulation for patients with acute low-back presentation,  there is a paucity of research on the benefit of manipulation for patients with chronic low-back pain.
Alternatively, outcome may be heavily influenced by the nature of the chiropractor-patient interaction, including more frequent visits and a process that engages the patient as a partner in the healing encounter.36 Clinical outcomes have been shown to be influenced by patients' health beliefs, the doctor-patient relationship, communication and information-sharing, and issues of power and control in treatment decision-making. [37-42] The influence of nonclinical factors appears to receive support from this study in that good outcome for medical patients was largely dependent on good psychological health at baseline, whereas the outcome for chiropractic patients was not. It may be that chiropractors dealt more effectively (successfully) with the psychosocial components of chronic low-back pain or, alternatively, that the psychological/emotional needs of chiropractic patients were being met independently of their physical (pain and functioning) needs.
The greater satisfaction found for chiropractic patients was consistent with previous studies reporting that chiropractic patients are more satisfied with the amount of information given them, their perception of their provider's concern for them, and their provider's level of comfort and confidence in dealing with the problem.  The paradoxical relationship between increased improvement and decreased satisfaction seen for medical patients is grounds for speculation. Perhaps pretreatment expectations were not met,  or the improvement experienced may have fallen far short of the amount anticipated. Alternatively, if the patients' needs for humanistic interactions and reassurance about their anxieties were not fulfilled by their providers, they might feel dissatisfied regardless of the condition-specific outcomes. [44, 45] Finally, we cannot rule out that greater satisfaction in the chiropractic cohort may be a function of differences in management style, practice setting, patients'ability to choose their provider type, or organizational characteristics of the health care facility (eg, size, complexity, professional autonomy). [21, 46, 47, 48]
This was a feasibility study, and, as such, it is characterized by a number of limitations. The proportion of eligible patients who were enrolled in the study was lower for medical clinics (35 to 62) than chiropractic clinics (68 to 80). However, the lower level of medical patient recruitment was due to the organizational complexities inherent in multiphysician clinics and was independent of patient characteristics. The follow-up rates for the 1-month questionnaire were acceptable for cold mailings. The degree of similarity between responders and nonresponders is not known, except that medical patients with greater severity at baseline were less likely than their chiropractic counterparts to respond to the 1-month follow-up questionnaire.
Self-selection to treatment group is a known bias in observational studies. One can never be sure that all of the vital factors affecting patient outcomes are known and are reflected in the data. However, our purpose was not to study efficacy as in a randomized clinical trial but to characterize patients and practices and to explore relationships as they exist in the community. We will be looking at both short-and long-term outcomes in the Health Resources and Services Administration-funded study for which Part I is completed and Part II is currently in progress. We anticipate that, with 3000 patients, we will be able to use sophisticated multivariate techniques to explore the association of relevant variables in greater detail.
The treatment and prevention of chronic recurrent low-back pain is a multifaceted problem. Chiropractors and family physicians need to be cognizant of the influence of non-clinical factors on patient progress. Physicians should develop strategies to harness this knowledge to improve the therapeutic encounter and potentially to improve outcomes.