Thursday, June 27, 2013
In a large-scale study, Rafia S. Rasu —at the University of Missouri-Kansas City School of Pharmacy — and colleagues examined various clinical practices for the outpatient management of chronic non-cancer pain (CNCP) [Rasu et al. 2013]. Results indicated that healthcare providers overwhelmingly preferred to prescribe non-steroidal anti-inflammatory drugs (NSAIDs) for CNCP, which the researchers say was in accordance with several clinical practice guidelines. However, was this optimal and safe medical practice?
For their study, reported in the June edition of The Journal of Pain, the researchers used data from more than 690-million patient visits to physician offices for chronic noncancer pain, compiled during 2000 to 2007 as part of the National Ambulatory Medical Care Survey (NAMCS) conducted by several United States government agencies. The sample included patients with commonplace CNCP conditions, ≥18 years of age (mean 53.3 years), 63% were female, and 87% were Caucasian.
During the study period, a CNCP diagnosis was involved in approximately 13% of qualifying ambulatory care visits — which should not be interpreted as indicating total chronic pain prevalence in the entire U.S. population. Nearly half (45%) of all visits for CNCP were to primary-care physicians, including family or general practitioners and internal medicine specialists.
Only 0.12% of all visits involved pain specialists, which the researchers suggest may depict a stark disparity between the need for pain services and their availability due to the paucity of pain specialists in the U.S. Additional specialists consulted for CNCP included orthopedic surgeons (14%), psychiatrists (11%), rheumatologists (6%), neurologists (5%), and others (22%).
Of particular interest to Rasu and colleagues were pain medication prescribing practices. Virtually all patients (99.7%) received some sort of medication therapy, and 29% received ≥5 prescriptions. The researchers found by far that NSAIDs were the most common medication class prescribed as first-line analgesic therapy. In fact, NSAID use was surprisingly high, with rates of 97% to 99% in all CNCP types studied, including: general chronic pain (eg, central pain syndromes and others); neuropathic pain (eg, shingles, CRPS/RSD, etc.); musculoskeletal pain (eg, fibromyalgia, myofascial pain); inflammatory pain (eg, arthropathies, vasculitis); mechanical/compressive pain (eg, low-back pain/sciatica, vertebral pathologies, etc.).
Several other important trends were apparent in the data…
- In contrast to NSAIDs, acetaminophen use was reported as very low at only 2%. However, acetaminophen was not typically administered by prescription and may not have been recorded accurately in patient records, and the researchers surmised that many patients with CNCP had already tried acetaminophen and not achieved sufficient pain relief by the time they visited a physician.
- SSRIs (selective serotonin reuptake inhibitors), tricyclic antidepressants, and other antidepressants, in total, were prescribed during more than a third (36%) of visits. At the same time, mental disorders were a frequently recorded comorbidity, occurring in 14% of patients with CNCP (cardiovascular disease was ranked a close second at 13%).
- Contrary to a popular perception that opioids are being over-prescribed for CNCP, they were noted in only 14% of visits overall, and more commonly for musculoskeletal and mechanical/compressive types of pain. No other medication class — eg, anticonvulsants, muscle relaxants, topical analgesics, corticosteroids, and others — was recorded as being prescribed during more than 7% of physician visits.
The researchers observe that the use of NSAIDs was consistent with recommendations in several pain-treatment guidelines, including: Assessment and Management of Chronic Pain from the Institute for Clinical Systems Improvement (ICSI, 2011 update) [access at Pain-Topics here]; Clinical Guidelines for the Use of Chronic Opioid Therapy in Chronic Noncancer Pain from the American Pain Society / American Academy of Pain Medicine (APS/AAPM, 2009) [access at Pain-Topics here]; and, Guidelines for the Assessment and Management of Chronic Pain from the Wisconsin Medical Society (WMS, 2004) [out of print, not accessible].
However, Rasu et al. concede that not all of those guidelines evaluate all treatment options or categorize CNCP conditions in exactly the same way. Additionally, many of the recommendations are based on expert consensus rather than high-quality data reflecting evidence-based medicine practices.
Overall, the researchers found that the use of non-medication approaches for management of CNCP were mentioned in only about 26% of patient visits. Exercise (15%), diet/nutrition advice (11%), and psychotherapy (9%) were most frequently noted, with modalities like CAM (complementary and alternative medicine), stress management, physical therapy, and weight reduction documented only in 2% to 5% of visits. “Combination treatment” encompassing both medication and non-medication approaches was noted to occur in essentially all visits (99.8%), but this broad metric does nothing to clarify the mix of specific approaches involved.
The researchers conclude that their evaluation of treatment practices in patients with CNCP showed an inordinately high use of NSAIDs, a low use of acetaminophen, and a likely underutilization of other guideline-recommended therapies for chronic pain, including medication or non-medication modalities and combination therapies. While they stress the need for adherence to accepted guidelines for treating CNCP, especially in primary-care practices, the researchers also appear to acknowledge that guidelines based on high-quality evidence are lacking.
This was a large and ambitious study encompassing a massive amount of data spanning an 8-year period. However, as we have consistently cautioned, such data-mining endeavors always have critical information gaps that leave many questions unanswered.
Other than general categories, data in the analysis by Rasu and colleagues did not indicate specific pain medications, or their dosages and duration of use. Patient adherence to prescribed therapy was not recorded, nor were there data regarding pain intensity and therapeutic effectiveness in relieving pain. These limitations precluded any objective observations regarding the frequencies of specific pharmacotherapies and clinical outcomes of the regimens.
The choice of treatment guidelines that Rasu et al. used for evaluating appropriateness of clinical practices is puzzling. The main focus of the APS/AAPM guideline, published in 2009, is on opioids, and we have previously criticized this document for making too many strong recommendations based on weak evidence [see Pain-Topics e-Briefing PDF here]. The WMS guideline was published in the organization’s journal nearly 10 years ago, and is no longer available at the journal or Wisconsin Medical Society websites; so, readers have no way of assessing the guideline’s applicability or current validity.
The ICIS guideline was updated in 2011; whereas, Rasu et al. apparently used an older edition (which they accessed in 2010). The latest iteration of this guideline suggests that NSAIDs “should be used for periodic flair-ups rather than for long-term chronic use.” There also are cautions about cardiovascular and GI adverse effects, so this guideline would not be supportive of the exceptionally high rates of NSAID prescribing found in the NAMCS database.
Rasu and colleagues duly note in their report that NSAIDs do incur important inherent risks, including recent heightened awareness of cardiovascular adverse events [also discussed in an UPDATE here]. Furthermore, the researchers acknowledge that in elderly persons the American Geriatrics Society recommends avoidance of NSAIDs due to cardiovascular and GI concerns; instead, acetaminophen is suggested as first-line therapy if practicable and, secondarily, opioid therapy if there are pain-related functional and quality of life impairments [also see UPDATE here].
Prescribing practices in the report by Rasu et al. were not stratified by patient age group, so we do not know if there was less NSAID use among elderly patients. Also, certain oral NSAIDs (eg, diclofenac, coxibs) have been noted to incur greater risks of cardiovascular adverse events, but NAMCS data do not indicate if these were largely avoided in favor of drugs with more favorable safety profiles.
Overall, in these copious data aggregated during a lengthy period of time, it appeared that physicians, largely primary-care providers, were not following practices consistent with current best evidence for the pharmacologic management of CNCP. An over-reliance on NSAID agents may have incurred significant harm due to adverse effects, particularly since cardiovascular disease was a comorbidity in 13% of patients, but this was not examined in the study by Rasu and colleagues. Concurrently, adjunctive non-medication approaches for pain management appeared to be greatly underused, which merits further research and explanation
REFERENCE: Rasu RS, Sohraby R, Cunningham L, Knell ME. Assessing Chronic Pain Treatment Practices and Evaluating Adherence to Chronic Pain Clinical Guidelines in Outpatient Practices in the United States. The Journal of Pain. 2013(Jun);14(6):568-578 [abstract here].