Opioids can be an effective painkiller following major surgery but prescribing them is not without risk.

While most patients successfully transition off opioids successfully after surgery, studies have shown that receiving a prescription for opioids can increase the risk of long-term use and an opioid use disorder (OUD).

Why do some patients fare better than others? And how can doctors know who to keep a closer eye on during the post-surgical period?

Mass General researchers recently found a compelling connection between vitamin D levels in the blood taken at the time of surgery and the risk of using opioids at higher doses, for longer periods of time, and for developing an OUD.

The results of the study, which was led by Yuhree Kim, MD, and Maryam Asgari, MD, MPH, from the Department of Dermatology, were recently published in the Journal of General Internal Medicine.

Why Vitamin D?

In previous studies, vitamin D deficiency has been linked to the increased severity of acute and chronic pain conditions as well as fibromyalgia and headaches. It has also been associated with increased pain perception and higher doses of prescribed opioid use in cancer patients and patients with chronic pain.

Based on this, the researchers believed that subjects with deficient vitamin D levels would be more at risk for problematic opioid use after surgery.

Details of the Study

To test their theory, they examined the medical records of 5,446 patients who had one of nine major surgical procedures between 2000 and 2014, including hip and knee replacements, Caesarean sections, appendix or gallbladder removal, sinus surgery and prostate surgery.

All of the patients in the study had their vitamin D levels checked within three months of their surgery.

Of the 5,446 patients in the study, 80% had sufficient levels of vitamin D when measured, 15% had insufficient levels and 5% were vitamin D deficient.

Confirming their hunch, they found that individuals with deficient vitamin D levels were more likely to use opioids for longer periods of time and to receive higher prescribed doses (measured by converting medication into daily morphine milligram equivalents).

Patients with vitamin D deficiency were also 1.5 times more likely to be diagnosed with an OUD within a year and a half of surgery when compared to patients in the suficient group. There was no statistical difference in OUD risk between those in the sufficient and insufficient groups.

Breaking down the demographics, the team found that patients with deficient levels of vitamin D were likely to be non-Hispanic Black, have lower levels of education and income, and a previous diagnosis of obesity — suggesting that socioeconomic status and preexisting conditions may also play a role.

What’s Next

The authors note several limitations of their study that can be addressed in future research. For one, it was limited to patients with private insurance and did not include Medicaid enrollees or patients without any insurance.

The team also did not have information about changes in patient vitamin D levels that may have occurred during the recovery period, or if patients received any vitamin D supplements in the post-operative period.

Future research could investigate whether providing vitamin D supplements after surgery can reduce the risk of problematic opioid use.

The team cautions that individuals with sufficient levels of vitamin D could still be at risk of excessive opioid use or OUDs as well.

“However, measuring vitamin D levels before major surgery could give doctors insight into who may be at greater risk.”

About the Mass General Research Institute
Research at Massachusetts General Hospital is interwoven through more than 30 different departments, centers and institutes. Our research includes fundamental, lab-based science; clinical trials to test new drugs, devices and diagnostic tools; and community and population-based research to improve health outcomes across populations and eliminate disparities in care.
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