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4 Articles in Volume 2, Issue #2
Blocking Out the Pain
Chronic Opioid Treatments
Effective Approaches: Study Questionnaires
Terrorism's Effect on Chronic Pain Perception: An Analysis of a Multi-center Cohort

Chronic Opioid Treatments

Selected chronic pain patients, treated with opioids in a structured program, can improve function and maintain employment.

The administration of opioids for chronic nonmalignant pain is a controversial issue, yet in general, there is currently no nationally accepted consensus regarding the treatment of chronic pain. There appears to be a select subpopulation of patients with chronic pain that can achieve sustained partial analgesia from opioid therapy without the occurrence of intolerable side effects or the development of aberrant drug-related behaviors.1 Randomized placebo controlled trials with a treatment duration of 1 week or more have shown that opioids are effective in providing analgesia in patients with chronic nonmalignant pain.2,3,4 Randomized trials, however, despite demonstrating analgesia, have not shown changes in functional outcomes and activity level.3,5

Impediments to the use of opioids include concerns about addiction, tolerance, diversion, fear of regulatory action, and side effects such as respiratory depression.6 Studies regarding neuropsychological functioning of patients taking chronic opioids are contradictory and suggest that opioids may impair performance by altering visuomotor coordination. However, the observed effects are not major and appear to be less significant than those observed with other classes of pharmacological agents which are increasingly being used to manage pain.7 Although temporary decline in cognitive function may occur when opioid dose is acutely increased, only a few non-significant cognitive effects are apparent in patients taking chronic and stable doses.8

The rationale for the use of opioids in non-malignant pain is not simply to treat pain, but to improve function. This study was conducted to investigate employment status and whether or not employment status is related to opioid dose in individuals treated chronically with opiates for non-malignant pain. We hypothesized that there would not be a strong relationship between opioid use and employment status.

Methods

A retrospective chart review was performed on all patients currently enrolled in our outpatient chronic pain management program. Exclusion criteria were 1) patients over 65 years of age, 2) homemakers, 3) patients with malignant disease, and 4) patients not currently taking opioid medication. These criteria exclude patients who are not expected to be working regardless of their chronic pain.

At each office visit, patients are asked to complete a questionnaire asking employment status, medication dosage, and whether pain is adequately controlled.

Our chronic pain management program is multi-disciplinary and involves a physiatrist, nurse, psychologists and physical and occupational therapists experienced in chronic pain. In our program, patients are prescribed opioid analgesics only after all other reasonable therapies have failed. These include injections, physical and occupational therapy, acupuncture, and various medications. At the onset of the program, patients must sign a contract stating that they will 1) use only one physician for opioid pain treatment, 2) use only one pharmacy for opioid medications, and 3) agree to random urine testing to evaluate compliance and screen for illicit drug use. Violators of this contract are subject to dismissal from the program.

Pain type was divided into four categories 1) musculoskeletal, 2) neuropathic, which included radiculopathy, 3) visceral, which included interstitial cystitis, chronic pancreatitis, and chronic prostitis, and 4) complex regional pain syndrome type I. Comparison of opioid doses was performed by converting various medications to oral morphine equivalents (Table 1). PRN medications were calculated at one half the maximal daily prescribed dose.

Levorphanol

Opioid Oral Equianalgesic Dose Conversion Factors9
Morphine 60mg
Hydromorphone 7.5 mg
4 mg
Meperidine 300mg
Codeine 200 mg
Oxycodone 30 mg
Propoxyphene 100 mg
Hydrocodone 120 mg
Methadone 20 mg
Fentanyl (transdermal) 25 ug/hr 10

Results

Of the 81 patients’ charts reviewed, 57 patients met our criteria. Thirteen patients were excluded because they were greater than 65 years of age and 11 were excluded because they reported to be housewives / homemakers. The mean age was 45 years (SD=9.6 years) with a range of 26 to 63 years. 29 patients were men and 28 patients were women. Of the patients meeting the above criteria, 59% were noted as being employed. Thirty-one patients were classified with musculoskeletal pain, 11 with neuropathic pain, 9 with complex regional pain syndrome, and 6 with visceral pain.

Opioid medications prescribed included oral codeine, transdermal fentanyl, oral hydrocodone, oral hydromorphone, oral meperidine, oral methadone, oral morphine, oral oxycodone, oral propoxyphene, and several fixed dose oral opioid combinations with aspirin or acetaminophen.

Table 1.

The mean daily dose among employed patients was 563 (SD=858) oral morphine equivalents and among unemployed patients was 452 (SD=682) morphine equivalents. A t-test revealed no significant difference between the employed and unemployed groups with regard to opioid use (t=0.52, p=0.61).

The mean opioid dosage in daily oral morphine equivalents for the four pain categories was as follows: musculoskeletal 306 (SD=288), neuropathic 444 (SD=924), complex regional pain syndrome 853 (SD=1067), and visceral 1247 (SD=1335). A one-way analysis of variance was statistically significant (F=3.44, p=0.02) between the musculoskeletal and visceral categories.

The most common diagnosis in our sample was low back pain (n=18). This sample was analyzed independently. The mean opioid dose was 331 (SD=241) oral morphine equivalents. Of these patients, 72% were employed. A t-test demonstrated no significant difference in opioid dose between the employed and unemployed groups (t=0.20, p=0.85).

Figure 1. Figure 2.

To examine the relationship between opioid use and employment in a more rigorous fashion, a simultaneous logistic regression equation was constructed with employment as the dependent variable. Four predictors were included: opioid dose in morphine equivalents, age, gender, and presence of neuropathic pain. The latter three variables were potential confounds that the authors wanted to control when examining the relationship between opioid use and employment status. The results of this analysis failed to find significant relationships between any of the independent variables and employment status (Table 2). Specifical ly, opioid medication dose was not a significant predictor of employment status (l2=0.40, p=0.53). Opioid dose in oral morphine equivalents and age were examined with regard to their functional form by way of various fractional polynomials. The assumption of linearity in the logit was not violated.

Logistic Regression Model
B Standard error Wald statisitc Sigma Exp(B) 95.0% Confidence
interval for odds ratio
Lower Upper
Morphine
equivalents .000
.000 .399 .527 1.000 .999 1.001
Gender .842 .610 1.905 .167 2.322 .702 7.677
Age -.001 .030 .002 .967 .999 .941 1.060
Neuropathic pain -1.051 .739 2.024 .155 .350 .082 1.487
Constant .119 1.481 .006 .936 1.126  

Discussion

Although there is increasing evidence to support the use of chronic opioid prescription for chronic non-malignant pain, there continues to be questions regarding opioid prescription to improve function.

The severity of chronic pain has been shown to be directly related to unemployment rate.11 Employment status during treatment of patients taking opioids for chronic nonmalignant pain has been utilized as a measure of functional outcome by several authors.

Tennant and Uelme12 reviewed 22 patients and found that 15 (68%) were able to return to employment. France, et al13 reported on 16 patients, of whom 15 suffered chronic low back pain. Structured follow-up interviews at a mean of thirteen months revealed that pain control was adequate in all cases and that 12 of the 16 patients appreciably increased their activity level at home or returned to work or school. The other four patients reported no change in level of function.

Tennant, et al14 reported on 52 patients who were already using opioids upon entering their program. Eleven (21%) of these patients were employed. Portenoy15 reviewed 39 patients and found a decrease in employment rate. Twenty-three patients were employed prior to the start of opioid therapy and 19 were employed during therapy. Plummer, et al16 reported on patients receiving intrathecal morphine. The observation was made that patients took a greater interest in relationships and surroundings and returned to work when it was available. Parrot17 reported on 30 primary care patients treated with opioids and stated that most have been able to function at a level necessary to continue with employment, family responsibilities, and religious and community activities. However, no specific numbers were reported in this study.

...patients took a greater interest in relationships and surroundings and returned to work when it was available... most have been able to function at a level necessary to continue with employment, family responsibilities, and religious and community activities.

Jamison et al5 reported on 36 patients with back pain who participated in a trial of naproxen vs. set-dose oxycodone vs. titrated dose oxycodone with sustained release morphine sulfate for 16 weeks. Each group was then given titrated dose oxycontin with sustained release morphine sulfate for 16 weeks. At presentation, 29% were employed. Six additional patients gained employment during the study, however, it was not clear if these patients were in the opioid treated group at the time of returning to work.

Comparison of functional outcomes in chronic pain patients is difficult for several reasons including selection bias18,19 and referral bias.1 Jamison, et al20 compared employment rates between opioid using and non-opioid using chronic pain patients. Significantly more of the non-opioid using patients were employed (76% vs. 48%), however, this study suffered a selection bias, with the opioid users likely suffering greater pathology.

Long term randomized trials of opioid analgesics for chronic nonmalignant pain3,5 have not shown an improvement in functional outcomes. The medication dose administered and the length of these studies may have influenced these results. Each of these studies had a maximum allowable daily dose of opioid medication. These maximum doses were less than the average dose used by patients in our study. The dose of opioid medication required for analgesia in chronic pain varies greatly among patients. Since opioid medications do not have a specific ceiling dose, perhaps a wider variation in dosing may be incorporated into future studies on functional outcomes. The longest period in these studies comparing opioid vs. non-opioid treatment is 16 weeks. Since chronic opioid treatment is for a much longer time than this, perhaps more time is required for complex functional outcome measures to be realized, such as employment and appropriate dose titration.

As hypothesized, we found no statistically significant relationship between opioid dose and employment. In this select group of patients (homemakers and retirees excluded), our findings of an overall employment rate 59% and an employment rate in low back pain patients of 72%, demonstrate that it is possible for patients on opioids in a structured chronic pain program to maintain employment.

Since many patients with chronic pain are relatively young and at prime earning potential, return to work can have a significant impact on patients’ economic and psychological well-being. Beyond that, a patient’s return to work removes him from disability, thereby decreasing the medical and economic burden to sosociety. Our patients have been able to return to a variety of vocations due to their motivation to do so and the benefits of appropriate use of various analgesics, including opioids.

Conclusion

When properly selected, patients with a variety of chronic painful conditions treated in a multidisciplinary fashion, can be maintained on opioids and continue to work. This includes 72 % of patients (homemakers and retirees excluded) with chronic low back pain, which has become an epidemic in our society. The opioid dose required for pain control does not appear to limit the possibility of employment.

Last updated on: January 26, 2012
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