Bastiaan Sallevelt

15 General Introduction Moreover, the risk-benefit balance in older multimorbid patients is often uncertain, which can complicate treatment choices [43,44]. Evidence-based guidelines for older patients with multimorbidity and polypharmacy are often lacking since they are largely underrepresented in clinical trials [45–48]. Although regulatory agencies are developing strategies to cover existing knowledge gaps in pharmaceutical patient care and drug product design for older people, the most currently available clinical practice guidelines are still single-disease oriented [45,49]. As a result, guideline recommendations are usually drawn from results in younger adults without multimorbidity or polypharmacy. In addition, difficulties may arise in communicating with older patients (e.g. due to cognitive impairment or hearing problems), impeding clear patient information, instruction for medication use and shared decision-making throughout the prescribing process. Lastly, frequent changes in medical conditions and co-medication make appropriate prescribing subject to highly dynamic factors in older patients over time, requiring close monitoring of pharmacotherapy. Monitoring is further compromised by involving multiple prescribers in patients with polypharmacy, which requires intensive collaboration between healthcare professionals to ensure adequate follow-up. Explicit tools for appropriate prescribing in older patients Due to the knowledge gap in single-disease-oriented clinical practice guidelines about optimal pharmacotherapy in older patients, several explicit tools have been developed to facilitate appropriate prescribing in this population [50]. Most explicit screening tools provide lists of drugs – often concerning concomitant diseases or medical conditions – frequently involved in drug-related harm in older people [51–53]. Although explicit screening tools are based on the best available evidence for the benefit-risk balance in older people, they do not consider individual patients’ needs and preferences and require clinical consideration. Therefore, these drugs are often referred to as ‘potentially’ inappropriate in older people. The Beers Criteria were the first list of explicit criteria developed to detect potential inappropriate prescribing in older people [54]. However, the Beers Criteria have several limitations that impede their use outside the United States [55]. For this reason, the Screening Tool of Older Person’s Prescriptions (STOPP) and the Screening Tool to Alert to Right Treatment (START) criteria were developed in Ireland (2008). This version was updated in 2015 by a European expert team resulting in STOPP/ START version 2 comprising 114 explicit criteria [56,57]. In contrast to other explicit screening tools, STOPP/START also includes potential drug omissions to detect under-prescribing. Hence, the STOPP/START criteria are the most widely used and extensively studied explicit screening tool for older patients in Europe [58]. Applying the STOPP/START criteria has been shown to reduce potentially inappropriate prescribing and adverse drug reactions while lowering healthcare costs in older 1