Evidence of specific cognitive deficits in patients with chronic low back pain under long-term substitution treatment of opioids.
BACKGROUND
There is a growing number of patients worldwide being treated with long-term opioids for chronic non-cancer pain, although there is limited evidence for their effectiveness in improving pain and function. Opioid-use related adverse effects, especially in cognitive functioning in these patients, are rarely evaluated.


OBJECTIVE
The present study investigated the cognitive functions of patients with chronic back pain who underwent long-term opioid treatment in comparison with those patients without opioid usage and healthy controls.


METHODS
A prospective, nonrandomized, cross-sectional study.


METHODS
Multidisciplinary pain management clinic, specialty referral center, University Hospital in Germany.


METHODS
In a prospective cross-sectional design, 37 patients with chronic back pain who underwent long-term opioid therapy (OP) were compared with 33 patients with chronic back pain without opioid therapy (NO) and 25 healthy controls (HC). Assessment of primary outcome included cognitive function such as information processing speed, choice reaction time, pattern recognition memory, and executive function. Other data included pain, back function, depression and anxiety, use of medication, and education status. The relationship between cognitive functions and anxiety/depression was analysed.


RESULTS
Both patient groups needed significantly longer time in information processing when compared to HC (Group 1: 41.87 ± 20.47 Group 2: 38.29 ± 19.99 Group 3: 30.25 ± 14.19). Additionally, OP patients had significantly reduced spatial memory capacity, flexibility for concept change, and impaired performance in working memory assessment compared to NO patients and HC. The impaired cognitive outcomes were significantly associated with pain intensity, depression scores, and medication use.


CONCLUSIONS
Limitations include small number of patients with heterogeneous opioid therapy and the nonrandomized observational nature of the study.


CONCLUSIONS
Our findings give a differential view into the cognitive changes from chronic back pain with and without long-term opioids treatment. Chronic back pain itself impairs some distinct cognitive functions. Long-term opioid therapy adds further cognitive impairment.
Marcus
M
Schiltenwolf
Michael
M
Akbar
Andreas
A
Hug
Ute
U
Pfüller
Simone
S
Gantz
Eva
E
Neubauer
Herta
H
Flor
Department of Orthopedics and Trauma Surgery, University Hospital of Heidelberg, Heidelberg, Germany; Spinal Cord Injury Center, University Hospital Heidelberg, University Hospital of Heidelberg, Heidelberg, Germany.
Haili
H
Wang
D000328:Adult; D000368:Aged; D000701:Analgesics, Opioid / Q000009:adverse effects*; D002755:Choice Behavior / Q000187:drug effects; D003072:Cognition Disorders / Q000139:chemically induced / Q000209:etiology*; D003430:Cross-Sectional Studies; D005260:Female; D005858:Germany; D006801:Humans; D007361:Intelligence Tests; D008137:Longitudinal Studies; D017116:Low Back Pain / Q000150:complications* / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011597:Psychomotor Performance / Q000187:drug effects; D011681:Pupil Disorders / Q000188:drug therapy; D021641:Recognition, Psychology / Q000187:drug effects; D018709:Statistics, Nonparametric; D055815:Young Adult
D000701:Analgesics, Opioid