Opioids after surgery overly prescribed in USA and Canada

By Dr. Liji Thomas, MDSep 5 2019

A new study covering several institutions shows that patients recovering from surgery in the US or Canada have a 50% chance of being treated with opioids. This is seven times as high as the corresponding percentage in Sweden. Within the US, the initial dosages are likely to be over 200 morphine milligram equivalents (MME) – much more than in Canada.

Do different countries use opioids at such widely varying rates for different indications? The current study aimed to answer this question.

Within 30 days of discharge, nearly half of all surgical patients in the United States received opioids in excess of 200 morphine milligram equivalents (MME). Image Credit: Kimberly Boyles / Shutterstock

How was the study done?

The researchers analyzed data from over 220 000 cases between the years 2013 and 2016, especially focusing on the percentage of prescriptions for opioid drugs that were filled within two periods – seven and 30 days post-operative or post-discharge – as well as the dosage and type of opioid used. They tried to match patients for age and medical history, and specifically picked out patients who had not been on any opioid for at least 90 days before surgery. The mean age varied from 42 to 45 years, with a male: female ratio of 30% to 40% between the three countries.

The researchers looked at patients who were convalescing from four common surgical procedures: appendicectomy, gallbladder removal, keyhole surgery for torn meniscal cartilage in the knee, and breast lump removal.

What does the study show?

The results were eye-opening: within the US and Canada, approximately 76% and 78% patients, respectively, got one or more opioid drugs by prescription within seven days of the surgery, while in Sweden, no procedure was followed by opioid prescription in more than a fifth of cases. The overall figure for filling opioid prescriptions within seven days of surgery in Sweden was just 11%.

Secondly, in the US, patients got about 250 MME of the opioid with the very first prescription on average – significantly higher than the 200 and 170 MME in Sweden and Canada, respectively. For morphine, the mean dispensed dose was about 440 MME while it was about 150 MME for codeine. At one month, 50% of US patients had taken opioids in doses of 200 MME or more, which is classified as a high dose. This was in contrast to 25% in Canada and only 5% in Sweden.

A notable exception to the low use of opioids in the post-operative period in Sweden was with breast excision, where over 50% of patients prescribed an opioid filled the prescription within seven days for over 220 MME.

Thirdly, US healthcare providers tended to prescribe hydrocodone and oxycodone, compared to codeine and tramadol which made up almost 60% and 45% of prescriptions in Canada and Sweden, respectively. Tramadol was used much more often, at almost 30% of prescriptions, in Sweden while codeine accounted for about 40% in Canada. The latter two drugs made up a measly 7% of opioid prescriptions in the US. However, tramadol and codeine (the latter only in low doses) was and is available as an over-the-counter drug in Canada, though tramadol is controlled in Sweden and in the US. Thus tramadol may have been widely used without prescription in Canada, accounting for some of the prescribing variations.

Combinations of an opioid with a non-steroidal anti-inflammatory drug (NSAID) were used by over 90% and 80% of patients in the US and Canada, respectively, but only 15% in Sweden.

What do we learn?

These differences in opioid prescription practices were described as “stark” by researcher Mark D. Neuman. The practice of giving opioids like codeine, tramadol and morphine for short-term postoperative pain is a routine intervention worldwide, but it seems to be overused in the US. This is underlined by the study design, which focused on three similar populations who underwent the same type of procedures. This makes it unlikely that any group would require different opioid use for postoperative pain.

Instead, the results probably mirror underlying differences in the way healthcare practitioners and patients perceive and use opioids for treating pain, as well as fundamental differences in the marketing and regulatory framework that promotes or limits opioid prescribing for postoperative pain management.

Earlier studies have shown important findings: patients in all three countries were equally satisfied with postoperative pain management and reported equal rates of pain after surgery; while non-opioid interventions in the US and Canada have succeeded in reducing opioid use after surgery without increasing pain. There is also poor correspondence between the amount of opioid prescribed at first and the need to repeat the dose, since more patients in the US received more opioid with the initial prescription but nonetheless went on to refill it within 30 days.

The observed trend is high-risk, as it may lead to drugs being diverted from legal channels to abuse, the use of opioids over the long term, and new-onset opioid dependency and addiction. This is particularly concerning in the light of increasing opioid overdose-related deaths all over the world, while the highest per capital opioid use is in the US and Canada.

Another researcher, Karim Ladha, points out, “Our findings point to systematic differences in practitioners' approaches to opioid prescribing, public attitudes regarding the role of opioids in treating pain and broader structural factors related to drug marketing and regulation.”

Neuman commented: “Our findings suggest real opportunities to encourage more judicious use of opioids before and after surgery for patients in the United States and Canada. It’s clear that we need to continue to identify ways to improve prescribing practices in the United States and Canada.”

The study was published in JAMA on September 4, 2019.