High-Cost and High-Dose Prescriptions of Cannabis-Based Medicines

A Comparison of Data From BARMER and the German Federal Institute for Drugs and Medical Devices (BfArM)

The efficacy and safety of cannabis-based medicines (CbM) has been a subject of controversy (1). There is some concern about their misuse (2). The risk of opioid misuse increases with the prescribed dose for non-cancer pain management (3). Data sets from the BARMER health insurance fund and the companion survey of the Federal Institute for Drugs and Medical Devices (BfArM) were analyzed to assess the prevalence of the risk signal of “prescription of higher doses”. Two data sources were analyzed in order to reduce the limitations of the companion survey (underreporting) (3) and of those arising from billing data obtained from health insurance funds.

Methods

The period from 1 April 2020 to 31 December 2021 for the companion survey (reports from the companion survey from 1 April 2020 refer to treatments starting from 1 April 2019) and the prescription period from 1 April 2019 to 31 January 2022 for BARMER were included in the analysis. High-dose therapy was defined in the BfArM data as follows: ≥ 3 grams/day for flowers without reference to tetrahydrocannabinol (THC) content or method of application, ≥ 20 mg THC/day for cannabis extracts and dronabinol, and ≥ 32 mg THC/day for nabiximols. Maximum-dose therapy was defined as double the high dose. Patients with a treatment duration of less than 12 months were considered by definition to be dropouts from the companion survey and were excluded from the evaluation.

The BARMER data did not allow dose calculations, so high-cost cases were analyzed as surrogates. Since there are considerable price differences and various price adjustments were made during the study period, high-cost cases were defined as incurred costs above the 90% percentile and the top ten (the ten insurees with the highest costs for CbM) as the highest-cost cases.

Indication groups were listed for both data sets (3). Demographic data and prescribing speciality groups were compared for high-dose versus normal-dose and high-cost versus normal-cost prescriptions.

Results

The analysis included 5816 BARMER insurees and 3677 BfArM cases. 11.6% of the BARMER prescriptions and 9.8% of the BfArM cases fulfilled the criteria for high-cost and high-dose prescriptions, respectively (Table 1). In both samples, three quarters of the prescriptions were written out for the age groups between 41 and 80 years. The proportions of females was lower for the respective high-cost (51%) and high-dose cases (44%) than for the normal-cost (63%) and normal-dose cases (57%). The most frequently prescribed CbM for high-cost and high-dose prescriptions was dronabinol (BEK 47%, BfArM 54%). Cannabis flowers accounted for 25% of the BARMER high-cost cases and 19% of the BfArM high-dose cases. A relevant difference in the CbM proportion of cannabis flowers was found in the high-cost cases as compared with the normal-cost cases (25% versus 7%) for the BARMER data, but not in the comparison of the high-dose versus normal-dose cases for BfArM (19% versus 16%). There was a relevant difference within the prescribing specialist groups for BARMER with respect to general practitioners (31% high-cost versus 23% normal-cost prescriptions). For BfArM, the proportion of anesthetists was higher for normal-dose cases (58.5%) than for high-dose cases (46%) (Table 1).

Table 1

Demographic and medical data of the insurees with high-cost versus those with normal-cost prescriptions of cannabis-based medicines

The following relevant differences were found when BARMER data were compared with BfArM data after stratification according to indication groups: male sex in the category “Other diagnoses” (64% versus 82%), prescription of cannabis flowers in the categories “Pain” (21% versus 13%) and “Oncology/Palliative” (27% versus 41%), and for cannabis extracts: “Oncology/Palliative” (13% versus 0%) and “Other diagnoses” (18% versus 4%). Of note was the higher proportion of primary care physicians in the categories “Pain” (32% versus 15%) and “Oncology/Palliative” (41% versus 12%), as well as the high proportion of other prescribers in the category “Other diagnoses” in both data sets (Table 2). Of the top ten highest-cost cases of BARMER (seven men, three women), four were in the “Pain” category, two in the “Oncology/Palliative” category, and four in the “Neurology” category. Thirty-one (0.8%) of the BfArM data sets were maximum-dose prescriptions, the majority of which were in the “Pain” category (N = 24) and “Other diagnoses” (N = 4). The maximum-dose prescriptions in the category “Other diagnoses” were predominantly written out for cannabis flowers in men and for the diagnoses mental disorders (hyperkinetic disorder, schizoaffective disorder).

Table 2

Demographic and medical data of the insurees with high-cost prescriptions of cannabis-based medicines

Discussion

Most of the dosages from the BfArM data are in the non-critical range. Maximum-dose and highest-cost cases are very rare. The data indicate a responsible approach when prescribing CbM.

Despite the different case definitions, there are no major differences in the incidence of potential risk indicators, with 12% high-cost BARMER cases and 10% high-dose cases in the companion survey. Assuming that some risk factors associated with opioid misuse, such as male sex, younger age, and mental disorders (4), also apply to CbM and that the inhalation of cannabis flowers is associated with a higher risk of misuse compared with oral or buccal administration of CbM (5), the relatively high proportion of cannabis flowers in the BARMER and BfArM datasets for the high-cost and high-dose cases and the high proportion of cannabis flowers in both datasets for the category „Other diagnoses“ can be interpreted as risk signals.

Limitation

There is no established definition of high-dose or high-cost therapies using cannabis-based medicines.

Beata Hennig*, Gabriele Schmidt-Wolf*, Alexandra Cristinziani, Peter Cremer-Schaeffer, Ursula Marschall, Frank Petzke, Winfried Häuser

Department of Medicine and Health Services Research at Barmer, Wuppertal, Germany (Hennig, Marschall)

Federal Institute for Drugs and Medical Devices, Federal Opium Agency, Bonn, Germany (Schmidt-Wolf, Cristinziani, Cremer-Schaeffer)

Pain Clinic, Department of Anesthesiology, University Medical Center Göttingen, Germany (Petzke)

Health Care Center for Pain Medicine and Mental Health, Saarbrucken-St. Johann, Saarbrucken, Germany (Häuser), [e-mail]

Department for Psychosomatic Medicine and Psychotherapy, Technical University of Munich, Germany (Häuser)

 * These authors contributed equally to this paper.

Conflict of interest statement
WH received fees for a continuing medical education presentation on cannabis-based medicines from Vidal MMI Germany.

The other authors confirm that there are no conflicts of interest.

Manuscript received on 07 June 2023, revised version accepted on 22 August 2023

Translated from the original German by Grahame Larkin M.D.

Cite this as:

Hennig B, Schmidt-Wolf G, Cristinziani A, Cremer-Schaeffer P, Marschall U, Petzke F, Häuser W: High-cost and high-dose prescriptions of cannabis-based medicines—a comparison of data from BARMER and the German Federal Institute for Drugs and Medical Devices (BfArM). Dtsch Arztebl Int 2023; 120: 813–4. DOI: 10.3238/arztebl.m2023.0201

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