Medical cannabis use often left undocumented in electronic health records

A total of 35% of the anonymous patients reported using cannabis for health reasons, including pain, sleep, stress, anxiety and depression, with 27% disclosing medical cannabis use within the past year. However, the sensitivity of EHR-documented medical cannabis use was only 10%.

"Prior to this study, the prevalence of medical cannabis use had not been estimated among a general sample of primary care patients," said co-lead author Dr. Gwen Lapham of the Kaiser Permanente Washington Health Research Institute, in Seattle.

Past studies, Dr. Lapham told Reuters Health by email, have only estimated the prevalence of medical cannabis use among patients in specialty-care settings or among those with specific health conditions.

Selecting from 108,950 adult patients (aged 18 years or older) who had completed a routine cannabis screen between January and September of 2019, the researchers invited 5,000 patients to participate in their confidential survey about cannabis use.

Using stratified random sampling, participants were oversampled both for a higher frequency of cannabis use within the past year, as well as for minoritized races and ethnicities to assure adequate representation.

To account for differences between respondents and nonrespondents, the researchers employed inverse probability weights, estimated by logistic regression from the initial sample group's demographic characteristics.

Ultimately, 1,688 of the 5,000 patients responded, a 34% response rate. Participants had a mean age of 51, 56% were female, 74% were white, 97% were non-Hispanic and 65% were commercially insured.

While the frequency of medical cannabis use documented in patients' EHR was only 4.8%, the confidential survey suggested a much higher frequency of cannabis use among primary-care patients.

The prevalence of patients reporting any cannabis use within the past year was 38.8%, with explicit medical use recorded as moderately lower than implicit medical use (26.5% vs. 35.1%).

Among those reporting cannabis use, 10.9% reported engaging in both medical and nonmedical use, while 15.5% reported medical use only and 12.3% reported exclusively engaging in nonmedical use.

When compared against the explicit medical use documented by the patient surveys, the medical cannabis use documented by electronic health records only had a sensitivity of 10.0%.

"Doctors don't ask and patients don't tell about their cannabis use," Dr. Kevin Hill, director of the Beth Israel Deaconess Medical Center's Division of Addiction Psychiatry in Boston, told Reuters Health by email. "Many doctors are skeptical about whether cannabis should be considered as therapy for the medical problems their patients describe. Patients often sense that skepticism and are therefore reluctant to raise the issue of cannabis."

"Millions of Americans are using cannabis, though," said Dr. Hill, who was not involved in the survey. "So it needs to be a regular part of conversations between doctors and patients."

Dr. Hill noted that the study cited several past journal articles documenting a lack of clarity from doctors on the potential benefits and risks of cannabis - highlighting the need for more education on the topic among medical professionals themselves.

"It is imperative that doctors understand the risks and benefits of cannabinoids and discuss them in a balanced fashion with their patients," he said. "Our patients are either interested in using cannabinoids for their medical problems or they are already doing so."