Association of Prescribed Medications with Outcomes from Rehabilitation for Musculoskeletal Pain

The lead article for this issue of the Journal of Musculoskeletal Pain [JMP] comes from investigators in Trondheim, Norway (1). The authors proposed to evaluate the association between three classes of controlled medications [centrally-acting analgesics (opioids), anxiolytics, and hypnotics] prescribed for patients involved in institutional rehabilitation programs for musculoskeletal pain with the patient’s outcomes from those interventions. Every participant completed the same self-report questionnaire at the beginning and the end of the rehabilitation program. The questionnaires focused on pain, health status, and socioeconomic factors. Linkage of the study subjects to the Norwegian Prescription Database gave the investigators access to the prescribed medications in the three classes of drugs. The term musculoskeletal pain would represent one manifestation of many specific medical conditions that could benefit from a rehabilitation program. In many cases, pharmacological therapy specific to the relevant diagnosis would have been initiated before the patient was referred for a rehabilitation program. In addition, the individual rehabilitation programs may have differed based on the given diagnosis and its severity, but recall that the focus of this study was upon prescriptions for three specific classes of controlled medications and their relationships to the outcomes resulting from the rehabilitation program. The investigators evaluated 1564 individuals in rehabilitation programs for musculoskeletal pain and found that 36.4% of the patients [N1⁄4 569] were given a prescription for a controlled medication in one of the three monitored classes. If a drug was prescribed, the authors assumed that it was used as directed. Interestingly, they found that the administration of centrally acting analgesics did not predict a good outcome among patients with musculoskeletal pain. Indeed, the prescriptions of hypnotics, and particularly of anxiolytics, were associated with the better outcomes. That being the case, it was surprising that there was no mention of sleep, sleep dysfunction, or insomnia among the authors’ measured outcomes. The authors found no relationship between the use of one of the classes of controlled medications and an existing diagnosis of an affective disorder like depression or anxiety. The second original contribution in this issue, relating to systematic assessment of delayed onset muscle soreness, comes from Joondalup and Brisbane, Australia (2). This study was designed to characterize post-exercise muscle pain when the exercise was intentionally eccentric. Questions answered by this study include the time course of visual analog scale subjective pain resulting eccentric exercise. Does this kind of muscle trauma cause allodynia? If so, does the time course of the resultant allodynia differs from that of the pain? To what extent does the subjective pain correlate with the allodynia? Do muscle pain or tenderness in this condition vary with the examined location in the length of the affected muscle? Finally, which of these measures do the investigators believe most accurately documents post-exercise muscle pain? The reader will be intrigued by the availability of answers to such precise questions. Since the eccentric exercise was experimentally induced unilaterally and consistently involved the no-dominant arm, it would have been interesting to know whether the paired contralateral muscle became symptomatic or developed allodynia to suggest a centrally mediated process. If there was referral to the contralateral unexercised muscle, did the referral more resemble myofascial pain syndrome or complex regional pain syndrome? A controlled clinical crossover study of the role of experimentally-induced peripheral pain [a form of attentional distraction] on head positioning was