High-Cost Users of Prescription Drugs: National Health Insurance Data from South Korea.

IMPORTANCE: In OECD countries, pharmaceutical spending reached around 800 billion USD in 2013, accounting for about 20% of total spending in the retail sector. Pharmaceutical expenditures are steadily increasing in South Korea, necessitating strategies to promote efficiency. OBJECTIVE: This study investigated factors associated with high-cost users (HCUs), who account for the majority of outpatient prescriptions in the total South Korean population. The top 20 frequently prescribed therapeutic subgroups were also investigated. DESIGN: This is an observational study performed using health insurance claims data in 2019. PARTICIPANTS: In total, 44,744,632 people (including 6,806,339 aged 65 years or older) who were prescribed outpatient medications were included. MAIN MEASURES: HCUs were defined as those for whom prescription drug costs were in the top 5%. Multivariate logistic regression analysis was performed using factors including age, insurance type, number of prescription drugs, outpatient visit days, prescription treatment days, and chronic diseases. RESULTS: HCUs accounted for 3.6 million (5% of the total population) and 1.4 million (21.1% of those 65 years or older). Furthermore, 4.1% of HCUs in the total population had few comorbidities. Male sex, older age, insurance (Medical Aid), comorbidities, chronic diseases, number of prescription drugs, outpatient visit days, and prescription days were all associated with an increased probability of being an HCU. The highest spending was found for B01 (antithrombotic agents) with 0.4 billion USD, followed by C10 (lipid-modifying agents) and A10 (drugs used in diabetes). The proportion of spending for HCUs among the general population was highest in L01 (antineoplastic agents), at 98.2%, and L04 (immunosuppressants), at 87.8%, whereas among the elderly, the highest proportions were found for B01 (antithrombotic agents), at 44.5%, and N06 (antidepressants), at 44.3%. CONCLUSION: Age and multiple chronic conditions were strongly associated with HCUs, and it seems necessary to reduce drug prescriptions in patients without complex comorbidities. Several measures should target those without multiple chronic conditions who are nonetheless HCUs.

Acute and 13-week subchronic toxicity studies of hot-water extract of Cynanchi wilfordii Radix in Sprague-Dawley rats.

Cynanchi wilfordii Radix (CWR) is a herbal medicinal plant that is well-known and used in Asian countries as a health food. In this study, acute and 13-week subchronic oral toxicity studies of hot-water extract of CWR (CWR-WE) were performed in Sprague-Dawley rats. For the acute toxicity study, CWR-WE was administered once orally to five male and five female rats at doses of 800, 2000, and 5000 mg/kg. Mortality, clinical signs, and body weight changes were monitored over 14 days. There were no treatment-related changes in these parameters and the approximate lethal dose of CWR-WE in male and female rats was determined to be > 5000 mg/kg. For the subchronic toxicity study, CWR-WE was administered orally once daily to male and female rats for 13 consecutive weeks at doses of 0 (vehicle control), 500, 1000, and 2000 mg/kg/day (n = 10 rats/sex/group). There were no toxicologically significant changes with regard to clinical signs, body weight, food consumption, ophthalmology, urinalysis, hematology, clinical chemistry, organ weights, necropsy findings, and histopathological findings. These results suggest that the oral no observed adverse-effect level of CWR-WE is > 2000 mg/kg/day for both sexes, although target organs were not identified.

Subchronic toxicity of Acorus gramineus rhizoma in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Acorus gramineus rhizoma (AGR) is the dry rhizome of Acorus gramineus Solander from the family Araceae that has been used as sedative, analgesic, diuretic, digestive and antifungal agent. AIM OF THE STUDY: To evaluate the no-observed-adverse-effect level (NOAEL) and the toxicity of AGR, following repeated oral administration to rats for 13 weeks. MATERIALS AND METHODS: AGR was administered by oral gavage to groups of rats (10 per group, each sex) at doses of 0 (control), 25, 74, 222, 667, or 2,000mg/kg/day, 5 times per week for 13 weeks. Mortality, clinical signs, body weights, food consumption, hematology, serum chemistry, urinalysis, vaginal cytology, sperm motility, sperm morphology, organ weights, gross and histopathological findings were compared between control and AGR groups. RESULTS: No mortality or remarkable clinical signs were observed during this 13-week study. No adverse effects on body weight, food consumption, urinalysis, hematology, serum chemistry, organ weights, gross lesion, histopathology, vaginal cytology, sperm motility or deformity were observed in any of the male or female rats treated with AGR. CONCLUSIONS: On the basis of these results, the NOAEL of AGR is determined to be 2,000mg/kg/day for male and female rats.

Acute and 28-Day Subacute Toxicity Studies of Hexane Extracts of the Roots of Lithospermum erythrorhizon in Sprague-Dawley Rats.

Lithospermum erythrorhizon has long been used as a traditional oriental medicine. In this study, the acute and 28-day subacute oral dose toxicity studies of hexane extracts of the roots of L. erythrorhizon (LEH) were performed in Sprague-Dawley rats. In the acute toxicity study, LEH was administered once orally to 5 male and 5 female rats at dose levels of 500, 1,000, and 2,000 mg/kg. Mortality, clinical signs, and body weight changes were monitored for 14 days. Salivation, soft stool, soiled perineal region, compound-colored stool, chromaturia and a decrease in body weight were observed in the extract-treated groups, and no deaths occurred during the study. Therefore, the approximate lethal dose (ALD) of LEH in male and female rats was higher than 2,000 mg/kg. In the subacute toxicity study, LEH was administered orally to male and female rats for 28 days at dose levels of 25, 100, and 400 mg/kg/day. There was no LEH-related toxic effect in the body weight, food consumption, ophthalmology, hematology, clinical chemistry and organ weights. Compound-colored (black) stool, chromaturia and increased protein, ketone bodies, bilirubin and occult blood in urine were observed in the male and female rats treated with the test substance. In addition, the necropsy revealed dark red discoloration of the kidneys, and the histopathological examination showed presence of red brown pigment or increased hyaline droplets in the renal tubules of the renal cortex. However, there were no test substance-related toxic effects in the hematology and clinical chemistry, and no morphological changes were observed in the histopathological examination of the kidneys. Therefore, it was determined that there was no significant toxicity because the changes observed were caused by the intrinsic color of the test substance. These results suggest that the no-observed-adverse-effect Level (NOAEL) of LEH is greater than 400 mg/kg/day in both sexes.

Subchronic toxicity study of Coptidis rhizoma in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Coptidis Rhizoma (CR) is a medical herb from the family Ranunculacease that has been used to treat gastroenteritis, dysentery, diabetes mellitus, and severe skin diseases. AIM OF THE STUDY: To evaluate the no-observed-adverse-effect level (NOAEL) and the toxicity of CR, following repeat oral administration to rats for 13 weeks. MATERIALS AND METHODS: CR was administered by oral gavage to groups of rats (n=10/group, each sex) at dose levels of 0 (control), 25, 74, 222, 667 or 2000 mg/kg/day 5 times per week for 13 weeks. Mortality, clinical signs, body weights, food consumption, hematology, serum chemistry, urinalysis, vaginal cytology and sperm morphology, organ weights, gross and histopathological findings were compared between control and CR groups. RESULTS: Urinalysis showed a significant increase in N-acety1-ß-glucosaminidase in males in the 2000 mg/kg/day group (P<0.01). However, no mortality or remarkable clinical signs were observed during this 13-week study. No adverse effects on body weight, food consumption, hematology, serum chemistry, organ weights, gross lesion, histopathology, vaginal cytology, sperm motility, or deformity were observed in the males or female rats treated with CR. CONCLUSIONS: On the basis of these results, the NOAEL of CR is determined to be 667 mg/kg/day for males and 2000 mg/kg/day for females.

Subchronic oral toxicity of evodia fruit powder in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Evodia, a fruit from Evodia rutaecarpa, has been used in oriental medicine, and since its various pharmaceutical actions, including anti-cancer activity, have become known, evodia has been widely used as a dietary supplement. However, information regarding its toxicity is limited. MATERIALS AND METHODS: Evodia fruit from Evodia rutaecarpa (Juss.) Benth. var. officinalis (Dode) Huang (0, 25, 74, 222, 667, and 2000 mg/kg) was administered orally five times per week for 13 weeks. Clinical signs, body weight, food consumption, hematology, serum chemistry, urinalysis, vaginal cytology, sperm morphology, organ weight, and gross and histopathological findings were evaluated. RESULTS: Urinary ketone body excretion was detected in males at 667 and 2000 mg/kg and in females at 2000 mg/kg. An increase in absolute/relative liver weight was observed in both sexes at 2000 mg/kg. Although levels of serum alanine aminotransferase, glucose, total cholesterol, and triglycerides were significantly reduced in males and/or females at 200 and/or 667 and 2000 mg/kg, all values were within normal ranges and were considered non-adverse. In addition, no treatment-related differences in body weight, food consumption, hematology, vaginal cytology, sperm morphology, or gross and histopathological examination were detected. CONCLUSIONS: The subchronic no-observable-adverse-effect level for evodia fruit powder following oral administration in rats is greater than 2000 mg/kg.