Prescribed Versus Taken Polypharmacy and Drug-Drug Interactions in Older Cardiovascular Patients during the COVID-19 Pandemic: Observational Cross-Sectional Analytical Study

Abstract

The study aimed to assess clinical pharmacology patterns of prescribed and taken medications in older cardiovascular patients using electronic health records (EHRs) (n = 704) (2019-2022). Medscape Drug Interaction Checker was used to identify pairwise drug-drug interactions (DDIs). Prevalence rates of DDIs were 73.5% and 68.5% among taken and prescribed drugs, respectively. However, the total number of DDIs was significantly higher among the prescribed medications (p < 0.05). Serious DDIs comprised 16% and 7% of all DDIs among the prescribed and taken medications, respectively (p < 0.05). Median numbers of DDIs between the prescribed vs. taken medications were Me = 2, IQR 0-7 vs. Me = 3, IQR 0-7 per record, respectively. Prevalence of polypharmacy was significantly higher among the prescribed medications compared with that among the taken drugs (p < 0.05). Women were taking significantly more drugs and had higher prevalence of polypharmacy and DDIs (p < 0.05). No sex-related differences were observed in the list of prescribed medications. ICD code U07.1 (COVID-19, virus identified) was associated with the highest median DDI number per record. Further research is warranted to improve EHR structure, implement patient engagement in reporting adverse drug reactions, and provide genetic profiling of patients to avoid potentially serious DDIs.

Keywords: cardiovascular disease; drug–drug interaction; electronic health record; epidemiology; health information system; polypharmacy; public health.

Figure 1

Structure of cardiovascular pathology in the study cohort according to data of electronic health records in 2019–2022. Detailed information on the clinical codes of International Statistical Classification of Diseases and Related Health Problems is available in Table S1.

Figure 2

ICD structure defining morbidities except for the letter “I” (I00–I99) in the cohort of cardiovascular patients according to data of electronic health records in 2019–2022 (only the letters the ICD codes begin with are shown). E—endocrine, nutritional and metabolic diseases; J—diseases of the respiratory system; K—diseases of the digestive system; M—diseases of the musculoskeletal system and connective tissue; N—diseases of the genitourinary system; U—codes for special purposes; H—diseases of the eye and adnexa and diseases of the ear and mastoid process; D—diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism; R—symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified; Z—factors influencing health status and contact with health services; C—neoplasms; G—diseases of the nervous system; L—diseases of the skin and subcutaneous tissue; S and T—injury, poisoning and certain other consequences of external causes; n/a—data not available. Detailed information on ICD codes is provided in Table S1.

Figure 3

(A): Median number of taken medications per record in women versus men. (B): Median number of taken versus prescribed medications per record. (C): Median number of drug–drug interactions (DDIs) between taken medications in women versus men. (D): Median number of serious DDIs between taken versus prescribed medications per record. Only statistically significant results are presented (p < 0.05).

Figure 4

Numbers of drug–drug interactions (DDIs) classified into contraindicated, serious/dangerous, monitor closely, and minor in the lists of prescribed and taken medications. * p < 0.05.

Figure 5

Pairwise combinations of prescribed drugs associated with serious/dangerous drug–drug interactions (DDIs) in the cohort of cardiovascular patients. Digits in parentheses indicate the absolute number of DDI occurrences for each pair of medications. Note: Impact of drug–drug interactions associated with the combinations “aspirin + captopril” and “aspirin + enalapril” may be considered insignificant due to the use of low-dose aspirin in the majority of cases. Administration of aspirin at doses less than 300 mg per day has little effect on the effectiveness of captopril and enalapril. Administration of aspirin in higher doses reduces the effectiveness of captopril and enalapril.

Figure 6

Pairwise combinations of taken drugs associated with serious/dangerous drug–drug interactions (DDIs) in the cohort of cardiovascular patients. Digits in parentheses indicate the absolute number of DDI occurrences for each pair of medications. Note: Impact of drug–drug interactions associated with the combinations “aspirin + captopril” and “aspirin + enalapril” may be considered insignificant due to the use of low-dose aspirin in the majority of cases. Administration of aspirin at doses less than 300 mg per day has little effect on the effectiveness of captopril and enalapril. Administration of aspirin in higher doses reduces the effectiveness of captopril and enalapril.

Figure 7

Median numbers of prescribed and taken medications and associated median numbers of drug–drug interactions (DDIs) and DDI indexes per record depending on primary ICD code (only the letters the ICD codes begin with are shown). Digits on the horizontal axis represent the corresponding numbers of patients in the electronic health records. Digits in red color on the horizontal axis highlight the top three most abundant ICD codes. The red line connects the bars corresponding to the most abundant ICD group of codes beginning with the letter “I”. Asterisk indicates significantly higher DDI index between the panels (* p < 0.05).