Worsening Trends in the Management and Treatment of Back Pain

Abstract

Importance

Back pain treatment is costly and frequently includes overuse of treatments that are not supported by clinical guidelines. Few studies have evaluated recent national trends in guideline adherence of spine-related care.

Objective

To characterize the treatment of back pain over the time period 1999–2010. We hypothesized that recommended care would increase, given the numerous clinical guidelines published over the past decade.

Design, Setting, and Patients

Using nationally representative data from the National Ambulatory Medical Care Survey and the National Hospital Ambulatory Medical Care Survey, we studied outpatient visits with a chief complaint and/or primary diagnosis of back/neck pain, as well as those with secondary complaints and diagnoses of back/neck pain. We excluded visits with concomitant “red flags” including fever, neurologic symptoms, or cancer. Results were analyzed using logistic regression adjusted for patient and provider characteristics and weighted to reflect national estimates. We also present adjusted results stratified by symptom duration and whether provider was the PCP.

Main Outcome Measures

We assessed imaging, narcotics, and referrals to physicians (guideline discordant indicators). Additionally, we evaluated NSAIDs/acetaminophen and referrals to physical therapy (guideline concordant indicators).

Results

We identified 23,918 visits for spine problems, representing an estimated 440 million visits. Approximately 58% of patients were female. Mean age increased from 49 to 53 years (p<.001) over the study period. NSAIDs/acetaminophen use per visit decreased from 37% in 1999–2000 to 25% in 2009–2010 (unadjusted p<.001). In contrast, narcotics increased from 19% to 29% (p<.001). While physical therapy referrals remained unchanged at ~20%, physician referrals increased from 6.7% to 14% (p<.001). X-rays remained stable at 17%, while CT/MRIs increased from 7.2% to 11% over the study period (p<.001). The above trends were similar after stratifying by acute versus chronic presentations, visits to PCP versus non-PCPs, and adjustment for age, sex, race/ethnicity, PCP-status, symptom duration, region, and metropolitan location.

Conclusions and Relevance

Despite numerous published clinical guidelines, management of back pain has relied increasingly on guideline discordant care. Improvements in management of spine-related disease represent an area of potential cost savings for the healthcare system with the potential for improving the quality of care.

Spinal complaints are among the most common reasons for visiting a physician and significantly contribute to healthcare expenditures. Over 10% of visits to primary care physicians relate to back or neck pain (hereafter referred to as back pain)—representing the fifth most common reason for all doctor visits, and accounting for approximately $86 billion in health care spending annually.^1–3 Indirect costs related to lost productivity amount to an additional $20 billion per year, which likely is an underestimate as the prevalence of chronic back pain may be rising.^3–5 Moreover, spending for these conditions has increased more rapidly than overall health expenditures from 1997–2005.⁶

Well-established guidelines for routine back pain stress conservative management including use of non-steroidal anti-inflammatory drugs (NSAIDs) or acetaminophen, and physical therapy, but avoiding early imaging or other aggressive treatments except in rare cases such as those demonstrating acute neurological compromise or other “red flags” such as a history of malignancy. In the absence of these features, routine back pain will usually improve with such conservative treatments within 3 months.^7–9 Prior research among patients with back pain revealed significant increases in use of CT/MRI exams, outpatient surgical procedures, and narcotic prescriptions, but many of these studies are over a decade old, limited to specific populations (e.g., Medicare), or study different aspects of utilization such as surgeries or hospitalizations.^6,10–15

In this context, we used nationally representative data on outpatient visits to physicians to evaluate trends in use of diagnostic imaging, physical therapy, referrals to other physicians, and use of medications over the 12-year period from 1999 until 2010. We hypothesized that with the additional guidelines released over this period,^16–22 use of recommended treatments would increase and use of non-recommended treatments would decrease.

METHODS

Data Sources

We used nationally representative data on visits to physicians available from the National Ambulatory Medical Care Survey (NAMCS) and the National Hospital Ambulatory Medical Care Survey (NHAMCS) for the time period 1999–2010. These surveys are designed to be combined to represent outpatient care in the United States.²³ NAMCS comprises a probability sample of outpatient visits to non-federal, office-based physician practices. Designed in parallel, NHAMCS consists of outpatient visits to hospital-based ambulatory departments, including outpatient clinics, and visits to emergency departments. NAMCS and NHAMCS share common design and survey variables and patient visit weights, and when analyzed together reflect national estimates.²⁴ Further documentation of survey methods are available at the NCHS website.²⁵

Data Collection Procedures

Both NAMCS and NHAMCS use a multi-stage probability sample design to obtain nationally representative samples of ambulatory patient visits in the US.²³ In the first stage of sampling, 112 primary sampling units (PSUs) were selected from among those used in the National Health Interview Survey. For the second stage, physician practices or hospitals were selected from within these PSUs. Finally, in the last stage, physicians or clinics sampled a subset of visits in their practices over a pre-defined time period. This design enables calculation of national-level estimates and associated standard errors using survey weights provided by the NCHS.²⁵

Data are collected using a standardized form completed during each patient visit. Both NAMCS and NHAMCS include data on the patient’s primary reason for visit (e.g., chief complaint) two other non-primary reasons for visit, up to 3 diagnoses derived from the International Classification of Diseases, Clinical Modification, Ninth Revision (ICD-9-CM), expected payer for the visit (e.g., Medicare, commercial insurance) various patient demographic characteristics, and medications listed during the visit.

Study Sample

To identify visits for spine-related conditions, we selected outpatient visits (excluding emergency department visits) with a chief complaint and/or a primary diagnosis of back or neck pain, as well as those with secondary complaints and diagnoses of back or neck pain, but unrelated primary reasons for the visit (e.g., hypertension). We used reason for visit codes from both NAMCS and NHAMCS to identify visits with a chief or secondary complaint of back pain (Table A1, Appendix).

In the subset of visits with a chief complaint of back or neck pain (just over 50% of visits in our sample) NAMCS and NHAMCS provide the duration or context of symptoms in five categories: (1) new onset (<3 months duration), (2) acute on chronic flare-up, (3) chronic routine (4) routine/preventative care visit, (5) pre or post-operative visit. This variable was missing 1.3% of the time. We defined ‘acute’ visits by combining those with new onset symptoms with those with acute on chronic flare-up. We then compared the ‘acute’ group’ with those with chronic routine symptoms. Of note, our results were not substantively different when the acute on chronic flare-up category was categorized as “chronic.”

We excluded visits with concomitant red-flag diagnoses or complaints including fever, weight loss, cachexia, neurologic symptoms, cancer, spinal fracture, myelopathy, or post-laminectomy syndrome that might be indicative of something other than routine musculoskeletal back pain.^26–28 As a sensitivity analysis we also excluded visits with a coexistent diagnosis with similar treatment options (e.g., knee pain, spasm of muscle) as well as those with concomitant trauma, fracture, various abdominal, musculoskeletal, neurologic, pulmonary, and infectious diagnoses. When including these visits, however, the results were similar (Table A3, Appendix), so we included these visits in our final analyses.

Main Outcomes Measures

We focused on three types of measures: (1) referrals for physical therapy or to other physicians; (2) use of imaging, including both CT/MRI and plain x-ray; and (3) use of medications including non-steroidal anti-inflammatory drugs (NSAIDs, including COX-2 inhibitors), acetaminophen (including both prescription and over-the-counter NSAIDs and acetaminophen), narcotics, tramadol, benzodiazepines and muscle relaxants (e.g., cyclobenzaprine), and agents to treat “neuropathic” pain (e.g., gabapentin). We considered NSAIDs or acetaminophen use as guideline concordant, and considered narcotic prescriptions as guideline discordant.²² Before 2003, NAMCS and NHAMCS only collected data on up to 6 drugs; therefore, in order to maintain consistency over time, we limited analysis of all years to the first 6 drugs listed.

We considered referrals for physical therapy to be concordant with current guidelines, but referrals to other physicians, presumably for consideration of treatments such as injections or surgery to be discordant with current guidelines. We also considered use of imaging studies for routine back pain to be discordant with clinical guidelines. Although the American College of Physicians guidelines were published in 2007, clinical guideline recommendations have remained generally consistent across specialties and around the world since the 1990s (see also Tables A8 and A9, Appendix).^29,30 Moreover, although some visits classified as guideline discordant might in fact be appropriate if additional clinical data (e.g., neurologic examination) were available, our focus is less on the proportion of guideline adherent treatments and more on trends over time, and we have no reason to suspect that the proportion of visits with indications for various procedures or treatments would have changed over time.

Finally, using logistic regression pooled across the entire study sample and including a control variable for year, we evaluated factors independently associated with ordering CT/MRI studies, narcotic medication use, and referring to another physician—the three outcomes we felt were most important.

Stratified Analyses

In order to evaluate the degree to which symptom duration affected our results, we analyzed the subset of visits with a chief complaint of back pain after stratifying by acute versus chronic presentations as defined above.

We also stratified our analyses of the full sample based on whether the provider identified herself as the patient’s PCP or not. We also assessed interactions between visit year and symptom duration, and visit year and PCP-status. Additionally, we stratified results by data from NAMCS versus NHAMCS (Table A10, Appendix). Finally, because comorbid conditions were not collected until 2005, we examined trends in the 14 comorbid conditions collected from 2005–2010 using Χ² tests.

Statistical Analysis

We assessed unadjusted trends using bivariable logistic regression where appropriate and evaluated categorical variables using Χ² tests. For each outcome measure, we report proportions of utilization for each time interval after pooling the survey data into 6 two-year intervals as recommended by the NCHS (1999–2000, 2001–2002, 2003–2004, 2005–2006, 2007–2008, and 2009–2010). For adjusted and stratified analyses, we estimated logistic regression models for each outcome of interest focusing on a linear trend for each two-year interval, and adjusting for age, sex, race/ethnicity, insurance status, whether the provider was the PCP, location in a metropolitan area, region, and the duration of symptoms when available (of note, because physician specialty information was only available in NAMCS, this variable was not included in our models; however, sensitivity analyses in the NAMCS subset revealed that the presence of specialty variables did not alter our results). Race/ethnicity was defined by the providers completing the survey instruments. We divided race into three categories: White, Black, and Other, which includes persons of Asian, Native Hawaiian, Pacific Islander, American Indian, or multiple races. We then re-categorized patients of any race who were identified as Hispanic in order to create a single four-level race/ethnicity variable.

All analyses were performed using SAS-callable SUDAAN, version 10.0 (RTI, Research Triangle Park, North Carolina) to account for the complex survey sample design. As noted above, we followed the NCHS recommendations for combining the NAMCS and NHAMCS datasets.²⁴ The Harvard Medical School Committee on Human Studies determined that this study was exempt from review.

RESULTS

We identified 23,918 visits related to back pain, representing an estimated 440 million visits over the 12-year period, or an average of 73 million visits per year. The number of patient visits related to back pain increased over the time period from 3,350 visits in 1999–2000 (representing 61 million visits, or 3.1% of all visits) to 4,078 visits during 2009–2010 (representing 87 million visits or 3.5% of all visits). Table 1 summarizes trends in visit characteristics among patients presenting with back pain (Table A5 in the Appendix provides year-by-year trends). Mean age increased from 49 to 53 years (p<.001), while the proportion of females remained stable at 58%. Seventeen percent of visits were from Medicare enrollees in 1999–2000 as compared with 28% in 2009–2010 (p=.01). Among those with a chief complaint of back pain (51% of sample), the proportion with acute or new onset symptoms fell from 62% in 1999–2000 to 59% in 2009–2010, while those with chronic symptoms increased from 30% to 37% during the same time period (p<.01). Comorbidities did not significantly change with the exception of asthma, which increased from 3.6% in 2005–2006 to 6.5% in 2009–2010 (p<.01,Table A6, Appendix).

Table 1.

Patient and Visit Characteristics over Time (% of Visits)

Year (Sample n)	1999–2000 (n=3,350)	2009–2010 (n=4,078)	P-value
Age (mean)	49	53	<.001
Female Sex	58	58	.79
Race/Ethnicitya
White	77	77	.78
Black	11	12
Hispanic	7.9	7.7
Other	3.3	3.6
Insurance Status
Private	49	46	.01
Medicare	17	28
Medicaid	6.8	9.2
Workers' Comp	15	7.9
Uninsured	11	9.0
Identified PCP	49	44	.22
Specialtyb
Primary Care	56	54	.60
Neurology/Orthopedic Surgery	18	16
All other specialties	26	30
Metro Area	84	88	.41
Region
Northeast	21	18	.80
Midwest	22	23
South	31	41
West	27	18
Nature of Back or Neck Pain
Chief Complaint Acute or New Onset	33	27	<.01
Chief Complaint Chronic	16	17
Chief Complaint Pre/Post Op	3.7	0.97
Chief Complaint Preventative Visit	0.57	1.1
Primary Diagnosis Only	15	17
Non-primary Diagnosis and Complaint	31	37

^aHispanic origin may include patients of any race. Other race/ethnicity includes persons of Asian, Native Hawaiian, Pacific Islander, American Indian, or multiple races.

^bPhysician specialty was only available in NAMCS, the number of visits or denominator for this variable therefore was n=1,604 in 1999–2000 and n=2,228 in 2009–2010.

Unadjusted Trends in Utilization

Medications

Use of NSAIDs/acetaminophen fell from 37% in 1999–2000 to 25% in 2009–2010 (p<.001, Table 2). In contrast, use of narcotics increased from 19% to 29% during the same time period (p<.001 for trend). Muscle relaxants and benzodiazepines increased from 20% in 1999–2000 to 24% in 2009–2010 (p<.001) and use of neuropathic agents more than doubled, climbing from 3.4% to 7.9% during the same time period (p<.001).

Table 2.

Unadjusted Utilization over Time (% of Visits)

Year (sample n)	1999–2000 (n=3,350)	2001–2002 (n=3,882)	2003–2004 (n=3,956)	2005–2006 (n=4,090)	2007–2008 (n=4,562)	2009–2010 (n=4,078)	P-value
Medications
Narcotics	19	20	23	27	34	29	<.001
Tramadol	3.0	2.5	1.7	2.6	4.4	4.9	.001
Neuropathic	3.4	3.7	4.9	5.1	11	7.9	<.001
Benzo/Relaxant	20	21	23	22	26	24	.023
NSAIDs/APAP	37	31	32	29	27	25	<.001
Referrals
Physical Therapy	21	15	18	15	14	19	.69
Other Physician	6.8	13	11	11	15	14	<.001
Imaging
X-Ray	17	15	13	16	16	17	.61
CT/MRI	7.2	8.2	7.3	11	11	11	<.001

Abbreviations: Benzo/Relaxant, benzodiazepines and muscle relaxants; NSAIDs, non-steroidal anti-inflammatory drug; APAP, acetaminophen; CT/MRI, computed tomography or magnetic resonance imaging.

Referrals and Imaging

Referrals to physical therapy remained unchanged at approximately 20% across the study period, but referrals to other physicians rose from 6.8% in 1999–2000 to 14% in 2009–2010 (p<.001). There was no observed change in the use of plain radiographs (~17% across the study period), but use of MRI/CT scans increased from 7.2% in 1999–2000 to 11% in 2009–2010 (p<.001).

Adjusted and Stratified Trends in Utilization

After adjustment, trends in utilization did not differ substantively from the unadjusted findings. Figure 1 shows adjusted proportions of referrals to physical therapy, referrals to physicians, narcotic and NSAIDs/acetaminophen use over time.

Figure 1.

Adjusted* Proportions of Referrals and Selected Drugs Over Time

* This figure shows estimates adjusted for age, sex, race/ethnicity, region, insurance type, symptom duration/context, whether the provider was the PCP, and whether the visit was located in a metropolitan area.

Stratified analyses of visits with a chief complaint of back pain comparing visits with acute versus chronic pain revealed similar trends for the two groups over the study time period (Table 3). Among patients with chronic symptoms, however, referrals to other physicians increased more rapidly when compared to those with acute symptoms (p=.01 for interaction with time), with referrals to physicians increasing from 3% to 13% for chronic symptoms and from 6.8 to 11% for those with acute symptoms during the study period (p<.001 and p=.07 for trend respectively). Although changes in referrals to other physicians among patients with acute symptoms and CT/MRI use among patients with chronic symptoms did not achieve statistical significance, use of these indicators also increased over time for both groups.

Table 3.

Adjusted^a Proportions of Utilization Stratified by Chief Complaint of Acute versus Chronic Back Pain over Time

Year (sample n acute) [sample n chronic]	1999–2000 (n=1,232) [n=572]	2001–2002 (n=1,360) [n=725]	2003–2004 (n=1,246) [n=831]	2005–2006 (n=1,276) [n=816]	2007–2008 (n=1,292) [n=979]	2009–2010 (n=1,112) [n=700]	P-value
Medications
Narcotics
Acute	19	19	25	29	28	28	<.001
Chronic	22	25	26	26	48	37	<.001
Tramadol
Acute	3.2	2.1	1.0	1.8	3.1	3.6	.39
Chronic	2.9	4.4	1.8	4.6	3.9	4.7	.23
Neuropathic
Acute	1.6	3.3	2.1	2.9	5.0	4.3	.02
Chronic	5.7	6.6	4.9	5.4	18	9.4	.001
Benzo/Relaxant
Acute	20	22	29	27	28	28	.003
Chronic	14	20	20	18	24	21	.12
NS AIDs/APAP
Acute	41	38	43	34	34	31	.001
Chronic	30	20	27	17	19	16	<.001
Referrals
Physical Therapy
Acute	18	12	14	16	13	18	.58
Chronic	9.7	3.9	16	9.5	6.4	10	.99
Other Physicianb
Acute	6.8	11	13	11	16	11	.07
Chronic	3.0	5.8	5.3	7.3	12	13	<.001
Imaging
X-Ray
Acute	22	17	18	20	20	17	.52
Chronic	7.4	6.7	4.3	8.6	6.8	9.6	.22
CT/MRI
Acute	6.7	6.5	5.3	10	12	11	.001
Chronic	4.5	6.2	3.4	6.1	6.7	7.6	.16

^aLogistic regression models adjusted for age, sex, race/ethnicity, region, insurance type, visit year, whether the provider was the PCP, and whether the visit was located in a metropolitan area.

^bInteraction with time was significant (p=.01).

Comparing visits to PCPs and non-PCPs also revealed similar trends, albeit with a few exceptions (Table 4). Among non-PCPs, CT/MRI use increased somewhat more rapidly when compared to visits to PCPs, increasing from 4.9% to 6.6% among PCPs (p=.02) versus 9.5% to 14% for non-PCPs (p=.002) throughout the study period; however, interactions with time were non-significant. Finally, NSAIDs/acetaminophen medications declined by nearly one half among PCPs (p<.001 for trend) while remaining flat among non-PCPs (p=.47 for trend), and this difference was statistically significant (p=.01).

Table 4.

Adjusted^a Proportions of Utilization by Identified Primary Care Physician (PCP) versus Non-PCP over Time

Year (sample n, PCP) [Sample n, non-PCP]	1999–2000 (n=1,216) [n=1,855]	2001–2002 (n=1,176) [n=2,446]	2003–2004 (n=1,294) [n=2,405]	2005–2006 (n=1,375) [n=2,561]	2007–2008 (n=1,408) [n=2,848]	2009–2010 (n=1,597) [n=2,209]	P-value
Medications
Narcotics
PCP	21	25	25	31	36	31	<.001
Non-PCP	16	14	20	23	31	28	<.001
Tramadol
PCP	3.3	1.9	1.3	2.8	4.0	4.1	.03
Non-PCP	2.1	2.3	1.8	1.7	4.0	4.9	.01
Neuropathic
PCP	2.9	3.8	4.1	4.7	7.5	6.2	<.001
Non-PCP	3.1	3.8	4.6	4.9	12	8.0	<.001
Benzo/Relaxant
PCP	22	24	25	25	30	28	.01
Non-PCP	12	12	17	16	19	19	.004
NSAIDs/APAPb
PCP	42	36	38	31	28	24	<.001
Non-PCP	28	22	27	24	23	23	.47
Referrals
Physical Therapy
PCP	12	6.2	9.3	9.9	8.1	9.7	.92
Non-PCP	28	23	23	19	18	25	.54
Other Physician
PCP	6.9	11	12	12	14	16	<.001
Non-PCP	6.1	14	11	11	15	11	.22
Imaging
X-Ray
PCP	13	13	13	12	12	12	.59
Non-PCP	21	14	13	17	19	18	.49
CT/MRI
PCP	4.9	5.4	5.7	7.9	8.1	6.6	.02
Non-PCP	9.5	9.9	8.7	14	14	14	.002

^aIn this table, our logistic regression models adjusted for age, sex, race, region, insurance type, visit year, duration of symptoms or context of visit (e.g., acute/new onset, chronic routine), and whether the visit was located in a metropolitan area.

^bInteraction with time was significant (p=.01).

Abbreviations: PCP, Primary Care Physician.

Correlates of Use

Table A7 in the Appendix presents the results of multivariable logistic regression models estimating use of CT/MRI studies, referrals to physicians, and narcotic prescriptions with visits pooled over the entire time period. Patients of Black, Hispanic, and other race/ethnicity had lower odds of receiving narcotic medications (0.77, 95% CI [0.65, 0.92], 0.60 [0.39, 0.95], and 0.51 [0.40, 0.65], respectively), as did female patients (0.86 [0.77, 0.96]). Uninsured patients had lower odds of being referred to other physicians (0.74 [0.57, 0.97]). A sub-analysis of specialists revealed that neurologists and orthopedic surgeons had higher odds of ordering CT and MRI exams (3.57 [2.60, 4.90]). Finally, providers in the Southern and Western U.S. had greater odds of prescribing narcotic medications (1.56 [1.21, 2.02] and 1.57 [1.22, 2.03] respectively).

Comment

In this nationally representative study of treatment patterns for patients presenting to physicians with back pain over the past decade, we observed several notable findings. First, we observed a significant rise in the frequency of treatments that are considered discordant with current guidelines including use of advanced imaging, such as CT or MRI, referrals to other physicians (presumably for procedures or surgery), and use of narcotics. Second, we also observed a decline in use of first-line medications such as NSAIDs or acetaminophen, but no change in referrals to physical therapy. Finally, although opiate prescriptions increased markedly over this time period, we also observed lower odds of receiving narcotics among female, Black, Hispanic, and other race/ethnicity patients, which may signify potential disparities in pain management that have also been noted previously.³¹

The 106% increase in referrals to other physicians is a previously unrecognized and important finding, as such referrals likely contributed to the recent rise in costly, morbid, and often ineffective outpatient spine surgeries observed in other studies.^32–35 Recent meta-analyses and research of lumbar fusion surgery have not revealed improvement in patient outcomes and demonstrate that these procedures lead to significant adverse consequences including 5.6% with life-threatening complications and 0.4% mortality.^36,37 Further, when comparing visits with the patient’s self-identified PCP versus those with another provider, we found that non-PCPs were much more likely to order advanced imaging. Presumably, this group includes those who perform procedures such as spinal surgery. Thus, these referrals from PCPs are likely to result in substantial downstream utilization that is not concordant with current guidelines.

We also found a 48% decline in first-line NSAIDs/acetaminophen use accompanied by a 53% rise in narcotic prescriptions, including a near doubling among patients presenting with chronic back pain. These results are not explained by a change in the frequency of acute versus chronic presentations or the extent to which patients were seen by their PCP versus another physician as similar trends were observed for each of these groups in our stratified analyses. Although some of the decrease in NSAIDs might have been due to the decline in use of COX-2 inhibitors, the dramatic fall in use of first-line therapies accompanied by the rapid rise in narcotic prescriptions raise significant concerns. A recent meta-analysis revealed that narcotics provide little to no benefit in acute back pain, have no proven efficacy in chronic back pain, and found that 43% of patients had concurrent substance abuse disorders—with aberrant medication-taking disorders as high as 24% of cases of chronic back pain.³⁸ Although we currently lack adequate data to make firm recommendations on narcotic medications, which may be indicated in certain circumstances, such increases in narcotic prescriptions may be contributing to a current crisis in public health: the rapid rise in narcotic overdose deaths parallels a reported 300% increase in the U.S. sales of prescription narcotics since the 1990s. In 2008, overdoses in narcotic analgesics led to an estimated 14,800 deaths—more than cocaine and heroin combined.^39–41

Our findings also confirm an inappropriate rise in advanced diagnostic imaging that has been seen previously,^12–14,42 with use of CT or MRI increasing by 53% in our study sample. Six randomized-controlled trials have shown that imaging in the acute setting provides neither clinical nor psychological benefit to patients with routine back pain²⁶ and multiple prospective studies have shown the lack of serious pathology in the absence of red flag symptoms.⁴³ In addition to being low value, the overuse of diagnostic imaging leads to more exposure to ionizing radiation. In 2007, a projected 1,200 additional future cancers were created by the 2.2 million lumbar CT scans performed in the U.S.^44,45 Finally, the dramatic rise in spine surgeries seen over the last decade is almost certainly related to the overuse of imaging. One study revealed that early MRI for acute back pain was associated with an eight-fold increased risk of surgery, while another found that regions with more MRIs do more surgeries, with 22% of the variability in spine surgery rates explained by rates of spine MRI use—more than twice the predictive power of patient characteristics.^46,47

Our study is subject to several limitations. Although we lacked complete data on the duration of symptoms, we present stratified results for acute versus chronic presentations that showed similar trends. Moreover, these visits comprised over half of our sample. Second, because NAMCS and NHAMCS are visit-level datasets, we lacked longitudinal data on treated patients. Consequently, we could not measure treatment patterns over time for individual patients. Because these visit-level data are collected in the same way each year, however, trends over time are likely to be reflective of changes in practice patterns and not to changes in the patient population presenting for treatment. A lack of major changes in most of our own population characteristics also supports this assessment, and those factors that did change (e.g., age, insurance status) were accounted for in our model. Furthermore, our analyses control for important potential confounders that might have changed over time such as the proportion of acute versus chronic visits and whether the visit was with a self-identified PCP. Finally, because comorbidity data were not collected until 2005, we could not use comorbidities in our adjusted analyses. However, our evaluation of trends in the 14 comorbid chronic conditions (including arthritis and depression) in our sample revealed significant increases only for asthma, which had very low prevalence rates that were unlikely to alter our results.

Despite numerous published national guidelines, management of routine back pain increasingly has relied on advanced diagnostic imaging, referrals to other physicians, and use of narcotics, with a concomitant decrease in NSAIDs or acetaminophen use and no change in physical therapy referrals. With healthcare costs soaring, improvements in the management of back pain represent an area of potential cost savings for the healthcare system while also improving the quality of care.