Observational, cross-sectional, study that included all patients over 55 years of age with multiple sclerosis under active follow-up in pharmaceutical care consultations at a tertiary level hospital between 1 November 2022 and 31 January 2023. This age cut-off was used because other authors have found that the presence of comorbidities in these patients appears even at an early age and that the average age of polymedicated patients is around 55 years [8, 9]. Demographic variables such as age, sex, date of MS diagnosis, type of MS, comorbidities, Charlson comorbidity index and the Expanded Disability Status Scale (EDSS) were collected. Regarding MS treatment, data were obtained on the drug and dose prescribed, date of onset and previous treatments.
In addition, variables related to concomitant pharmacological treatment were collected: medication, date of onset and cause of prescription (defined as comorbidity, for treatment of MS symptoms, symptomatic treatment of acute process or supplementation).
We analysed the presence of polypharmacy (defined as prescription of 5 or more active ingredients not including DMT), major polypharmacy (10 or more active ingredients not including DMT), treatment complexity index (dichotomised as high or low) and anticholinergic burden linked to home medication [10].
The prevalence of PIMDINAC criteria was defined as the main variable and classified into 2 categories: total (joint presence of PIM + DI + NAC criteria) and partial (isolated presence of some criteria). Factors associated with the presence of PIMDINAC criteria were also studied. The STOPP-START 2014 [11] criteria were used to identify PIM. The Lexicomp® database [12] was used to determine the IDs between DMT and concomitant medication, considering only those IDs of grade D (potential) or X (contraindications). To assess the NAC of both home medication and DMT, the multi-interval coefficient of dispensing in the pharmacy over the last 6 months was used, with a patient being considered adherent when treatment was available more than 90% of the time during the last 6 months.
Based on the data collected, pharmaceutical interventions aimed at the patient or the prescribing physician were carried out. The type of notification and the PIMDINAC criterion responsible for the intervention and the outcome of the intervention were recorded.
The corporate programmes of the Andalusian Health Service were used for data collection, including the electronic medical record, the in-hospital electronic prescription programme and the electronic prescription programme.
For descriptive statistical analysis, quantitative variables were summarised with mean and standard deviation, or median and interquartile range, in case of asymmetric data distribution. For categorical variables, frequencies and percentages were used.
To assess the relationship between categorical variables, the Chi-square test or Fisher's exact test was used. In the case of quantitative variables, the Student's t-test or Mann-Whitney U-test, depending on whether the distribution is normal or not. A p-value < 0.05 was considered statistically significant. Statistical analysis was carried out with R Commander® software.
This study was conducted with the approval of the Biomedical Research Ethics Portal of the Andalusian Health System and in accordance with good clinical practice and the ethical principles for medical research of the Declaration of Helsinki of the World Medical Association.