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Am Fam Physician. 2002;65(7):1319-1322

Clinical Scenario

A 42-year-old man presents with a one-day history of moderately severe low back pain that began after he bent over to pick up a newspaper.

Clinical Question

Are nonsteroidal anti-inflammatory drugs (NSAIDs) an effective treatment for low back pain?

Evidence-Based Answer

Patients can expect a modest improvement in global function with NSAID therapy, such as ibuprofen. There is no evidence that any particular NSAID or combination of medicines has superior efficacy in the treatment of low back pain.

Cochrane Abstract

Background. Worldwide, NSAIDs are the most frequently prescribed medications and are widely used to treat low back pain.

Objective. The objective of this systematic review was to assess the effects of NSAIDs in the treatment of nonspecific low back pain and to assess which type of NSAID is most effective.

Search Strategy. The authors searched the Medline and Embase databases and the Cochrane Controlled Trials Register (CCTR) up to and including September 1998 if reported in English, Dutch, or German. The authors also screened references given in relevant reviews and identified trials.

Selection Criteria. Randomized trials and double-blind controlled trials of NSAIDs in nonspecific low back pain with or without pain radiating to the legs were included.

Data Collection and Analysis. Two reviewers, blinded with respect to authors, institution, and journal, independently extracted data and assessed methodologic quality. A methodologic quality score was applied, and studies meeting at least six of 11 specified criteria were considered high-quality studies. If data were considered clinically homogeneous, a meta-analysis was performed using a fixed effects model for statistically homogeneous subgroups and a random effects model for statistically heterogeneous subgroups.

If data were considered clinically heterogeneous, a qualitative analysis was performed using a rating system with four levels of evidence (strong, moderate, limited, no).

Primary Results. A total of 51 trials (total number of patients: 6,057) were included in this review, of which 46 were published in English and five in German. Sixteen trials (31 percent) were of high quality. The pooled relative risk for global improvement after one week was 1.24 (95 percent confidence interval [CI], 1.10, 1.41) and for additional analgesic use it was 1.29 (95 percent CI, 1.05, 1.57), indicating a statistically significant effect in favor of NSAIDs compared to placebo. The results of the qualitative analysis showed that there is conflicting evidence that NSAIDs are more effective than acetaminophen for treatment of acute low back pain, and that there is moderate evidence that NSAIDs are not more effective than other drugs for treatment of acute low back pain. There is strong evidence that various types of NSAIDs are equally effective for treatment of acute low back pain.

Reviewers' Conclusions. The evidence from the 51 trials included in this review suggests that NSAIDs are effective for short-term symptomatic relief in patients with acute low back pain. There does not seem to be a specific type of NSAID that is clearly more effective than others. Sufficient evidence on treatment of chronic low back pain is still lacking.

The Cochrane Abstract is a summary of a review from the Cochrane Library. It is accompanied by an interpretation to help clinicians put evidence into practice. Glenn Griffin, M.D., M.Sc., M.Ed., Fred Tudiver, M.D., C.C.F.P., F.C.F.P., and William D. Grant, Ed.D., present a clinical scenario and clinical question based on the Cochrane Abstract, along with evidence-based answers and a full critique of the abstract.

Cochrane Critique

Did the authors address a focused clinical question? Yes.

Were the criteria used to select articles for inclusion appropriate? Yes.

Is it likely that important relevant articles were missed? No.

Was the validity of the individual articles appraised? Yes.

Were the assessments of studies reproducible? Yes.

Were the results similar from study to study? No. There was much variation from study to study, and the authors developed a reasonable strategy for dealing with this variation. They did a quantitative analysis on studies that were clinically homogeneous and a qualitative analysis on those that were clinically heterogeneous.

Can the results be applied to patient care? Yes.

Do the conclusions make clinical and biological sense? Yes.

Are the benefits worth the harms and costs? Yes.

Separate analyses were performed for the primary outcome measures of pain intensity, overall improvement, functional status specific to back pain, and return to work. Qualitative analysis was performed if the studies were heterogeneous or if data required for statistical analysis were lacking.

Practice Pointers

Low back pain is a major health problem in the Western world. The disease is usually self-limited, but the pain can be severe. Specific causes of low back pain such as infection, neoplasm, osteoporosis, fractures, or rheumatoid arthritis were not studied. The authors stated that there was not enough information to determine the effectiveness of NSAIDs in the treatment of chronic low back pain, although one high-quality trial showed a clear benefit for NSAIDs over placebo.

In acute low back pain, several measures showed statistical evidence of slight overall short-term improvement with NSAIDs compared to placebo. There was no statistically significant difference in side effects. Included studies showed slightly greater effect in acute and chronic low back pain for NSAID therapy compared with acetaminophen therapy. NSAIDs were not more effective than muscle relaxants or narcotics in treatment of acute low back pain.

Heterogeneity and homogeneity
The terms heterogeneity and homogeneity are commonly used in systematic reviews and meta-analyses. Just as there is clinical significance and statistical significance, there is clinical heterogeneity and statistical heterogeneity.
If the included studies are considered to be similar to one another (in terms of types of studies, participants, interventions, and outcome measures), they are said to be clinically homogeneous. If the included studies are significantly different from each other in one or more of the above criteria, they are said to be clinically heterogeneous and should not be combined for analysis.
If a group of studies is statistically homogeneous, the results of each individual trial are compatible with the results of any of the others. In other words, the results of the individual trials are no more different from each other than they would be by chance alone. If the differences are greater than they would have been by chance alone, the trials would be statistically heterogeneous. There are also rules of thumb and statistical tests to measure heterogeneity/homogeneity. These are described in How to Read a Paper by Greenhalgh.1

NSAIDs were no more effective than physiotherapy or spinal manipulation for treatment of acute low back pain but were somewhat more effective than bed rest. There was no difference in effectiveness between different types of NSAIDs. There was no advantage to adding muscle relaxants to NSAIDs for treatment of acute low back pain. The usefulness of adding B vitamins to NSAID therapy was supported by very limited evidence.

Based on patient-oriented outcomes from this review, it is reasonable to treat acute or chronic low back pain with NSAIDs. All NSAIDs are equally effective, and all have minimal side effects, so generic ibuprofen is probably the best choice because it has fewer serious gastrointestinal side effects2,3 and lower cost. Acetaminophen is a reasonable, although slightly less effective, alternative.

Initial drug treatment for acute low back pain starts with ibuprofen in a dosage of 600 to 800 mg three times per day as needed unless contraindicated. Acetaminophen in a dosage of 650 to 1,000 mg four times per day as needed is a reasonable alternative. There is no benefit from using the more expensive brand-name NSAIDs. The new cyclooxy-genase-2 (COX-2) inhibitors (e.g., rofecoxib, celecoxib) provide no greater efficacy than ibuprofen,4 with a slightly smaller harm level. Two hundred patients need to be treated with a COX-2 inhibitor to prevent one gastrointestinal bleeding event,5 and these agents cost significantly more than generic ibuprofen. COX-2 inhibitors should typically be used in patients who are at significantly higher risk for gastrointestinal bleeding or peptic ulcer disease (i.e., those older than 75 years or with a previous history of gastrointestinal bleeding or peptic ulcer).6,7

Based on the evidence in this systematic review, there is no reason to treat patients with chronic low back pain differently than patients with acute low back pain.

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Copyright © 2002 by the American Academy of Family Physicians.

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