Drug-related problems: assessments of risk and relevance

Pharmacotherapy is the most frequently used form of treatment intervention. The benefits of the therapy need to be weighed carefully against its risks, as drugs also cause up to 25% of all emergency department visits. Preventable inappropriate prescribing and medication errors, including the patient’s own mishandling, manifest in drug therapy failures and adverse drug events, which subsequently may generate costly hospitalisations. Of the adult Swiss population aged over 65 years, 21% are prescribed a potentially inappropriate medication. Within this setting, medication reviews are a method of assessing the patient’s drug regimen regarding its appropriateness and the patient’s preferences in order to address inappropriate prescribing and prevent medication errors. Medication reviews reduce the number of drug-related problems (DRPs) and decrease drug-related emergency department visits as well as hospital length of stay. But medication reviews are a time-consuming intervention. In a country like Switzerland, where 35.9 full-time equivalents of clinical pharmacists should promote safe, economic, and appropriate medicinal therapies for 1.4 million hospitalisations per year, there is a demand for risk stratification and patient prioritisation. Newly developed algorithms that generate alerts for clinical pharmacists on pooled electronic data, however, do not take into account the patient-centred causes of DRPs. The Drug-Associated Risk Tool (DART) was developed to identify hospitalised patients at greater risk of DRPs and in need of clinical pharmacy services, i.e. medication reviews. As a self-administered questionnaire for patients, the screening tool assesses items concerning the patients’ medical information in combination with their opinions and concerns about the pharmacotherapy whilst not increasing the workload of any caregiver.
In this thesis, the DART was validated regarding its ability to discriminate between patients with lower and higher numbers of DRPs. Issues concerning the patients’ current pharmacotherapy were identified with a medication review with pooled data on drug regimens, diagnoses, laboratory values, and structured patient interviews. The medication reviews combined implicit and explicit criteria of inappropriate prescribing to balance the benefits and drawbacks of each approach. This thesis looked into the performance of the criteria used and reports on the number of DRPs identified with each method. The structured patient interview was newly developed by combining a remunerated public pharmacy interview on adherence with questions on concerns about the medication. This thesis describes the benefits of the patient interview by presenting the type of DRPs identified and weighs it against the additional clinical pharmacy resource requirements. The DART validation study also necessitated the use of a tool to estimate the potential relevance of pharmacists’ interventions. With the translation and subsequent reliability testing of the French tool CLEO, this thesis reports on the performance of a validated German version. CLEOde may help German-speaking pharmacists to estimate the potential relevance of their own interventions in three distinct dimensions: Patient-centred clinical, cost-focusing economic, and institution-based organisational. The study focused on interrater and test–retest reliability of CLEOde and presented an overview of clinical pharmacists’ activity within three Swiss-German hospitals. This thesis also critically evaluated the performance of another tool for risk stratification and patient prioritisation concerning one specific drug-related problem: The RISQ-PATH score and its ability to predict drug-induced QT-prolongation and heart arrhythmias.
The thesis encompassed the execution of medication reviews, including patient interviews, for 110 geriatric patients within a study period of 10 months, identifying 595 DRPs estimated to be of minor to lifesaving relevance. The performed patient interviews identified over one third of all DRPs with insufficient patient knowledge and incomplete patient documentation as most the prominent and not otherwise identifiable causes. This thesis reports an average time of 16.6 minutes needed for the individual structured patient interviews. The ability of the DART to distinguish between patients with low and high numbers of current DRPs was demonstrated: Cluster analysis and subsequent discriminant function analysis allowed for an item reduction to five questions associated with the number of DRPs. These questions allow targeting patients who would benefit most from direct engagement and bedside interventions. CLEOde was used by 10 clinical pharmacists working in three hospitals during 13 days of routine clinical pharmacy services to estimate the relevance of 324 performed pharmacists’ interventions. The use of CLEOde was seen as appropriate, acceptable, feasible, and precise. Statistical analysis showed good interrater reliability and excellent test–retest reliability for the clinical and economic dimension, whereas the organisational dimension achieved poor interrater and fair test–retest reliability. By critically examining the association between the RISQ-PATH scores and the measured QTc intervals, we identified an already previously present prolonged QTc interval as moderating variable, necessitating subgroup generation for score interpretation. These results also allowed this thesis to articulate a simple code of practice when handling drugs with the potential to prolong the QTc interval.
This thesis, entitled “Drug-Related Problems: Assessments of Risk and Relevance,” presents a validated self-administered patient questionnaire to stratify for drug-related risk, a validated assessment to estimate the relevance of drug-related problems, a structured patient interview to identify issues on drug-related adherence, handling, and concerns, and a valid score to detect patients at risk of drug-induced QT-prolongation.