Background and importance The combination of drugs with anticholinergic action can cause side effects in people with morbidity. This risk increases with age and frailty. There are different scales to estimate the anticholinergic risk (AR) but there is substantial variability between them. The Anticholinergic Burden Calculator (ABC) tool allows the calculation of the Drug Burden Index (DBI), which takes into account the prescribed dose and includes sedative drugs.

Aim and objectives To determine the AR of patients admitted to a second-level hospital.

To analyse their comorbidities and to relate them to possible anticholinergic side effects.

Material and methods Cross-sectional study carried out with patients admitted to the hospital ward. Patients older than 65 years and with more than five prescribed drugs were included in the study. The variables collected from the electronic medical history were: age, gender, morbidity, hospital service, drugs and dose. To obtain the AR, the ABC tool was used, expressing the values in DBI. According to AR, the patients were classified into three groups: without risk (0), medium risk (<1) and high risk (≥1).

The comorbidities of each patient were analysed. Those that were related to anticholinergic effects were selected and classified into two groups: (a) somatic symptoms (dry mucosa, constipation, urinary retention) and (b) neuropsychiatric symptoms (cognitive and functional dysfunction, agitation, falls).

Results A total of 183 patients were included: 60.1% women with median age 84.3 (SD 8.9) years. According to the DBI, patients were classified into three groups: without risk (15.3%), medium risk (40.4%) and high risk (44.3%). The total average DBI obtained was 0.97 (SD 0.86) and in the high-risk group was 1.7 (SD 0.78).

Comorbidities related to possible anticholinergic effects were found in 49.2% (n=90) of the patients. This percentage increased to 55.6% (n=50) by focusing on high-risk patients compared to medium-risk patients (32.2% n=29) and without-risk patients (12.2%, n=11). 87.4% of the comorbidities were neuropsychiatric symptoms.

Conclusion and relevance Most of the patients presented anticholinergic risk. Half of them had comorbidities that could be related to the effects of anticholinergic drugs. These comorbidities increased in direct proportion to anticholinergic risk. It would be advisable to implement a hospital protocol to reduce the anticholinergic burden.

Conflict of interest No conflict of interest