In people with chronic pain, there is no evidence on the effect of long-term opioids on pain, function, or quality of life

Chou R, Turner JA, Devine EB, et al. The effectiveness and risks of long-term opioid therapy for chronic pain: a systematic review for a national institutes of health pathways to prevention workshop. Ann Intern Med. 2015;162:276-86.

Review questions

In people who have chronic pain, what is the effect of long-term treatment with opioids on pain, function, and quality of life? What are the harms associated with long-term treatment with opioids?

Background

Chronic pain is pain that lasts longer than 3 months or past the time that is common for healing. It can lead to reduced quality of life and disability. Opioids are painkillers and include morphine, methadone, and oxycodone. These drugs are often prescribed for chronic pain, but they have side effects, including overdose.

How the review was done

The researchers did a systematic review, searching for published studies up to August 2014. They found 39 studies.

People in the studies were 18 years of age or older (average age 46 to 73 years) and had chronic pain.

The studies compared long-term opioid treatment (taking the drug most days for more than 3 months) with placebo, no treatment, another drug, nondrug therapy, or another dose or form of opioid.

What the researchers found

No randomized controlled trials measured pain, function, or quality of life after 1 year of opioid treatment compared with placebo, no treatment, or another drug.

Harms were assessed in 19 studies, and there was weak evidence that long-term opioid treatment:

• increased the number of people who  abused or were addicted to opioids, or who had an overdose; and
• increased the risk of a heart attack.

There was limited evidence on the effectiveness and harms of different doses and forms of opioid treatments, which were compared in 17 studies.

Conclusions

In people who have chronic pain, there are no studies measuring the effect of long-term treatment with opioids on pain, function, or quality of life. Long-term treatment with opioids is associated with increased drug abuse, addiction, overdose, and heart attacks.