Discussion
PIP was observed in between 44 and 53% of fallers over the age of 70 years presenting to our ED using Beers and STOPP33 criteria, respectively. The significant prevalence of PIP in this group has not previously been reported. Falls in an older patients presenting to ED should trigger a medication review as part of a comprehensive assessment. Our study revealed a high prevalence of PIP in this cohort with no substantial improvements in prescribing following the event. A mixed picture was seen in admitted patients, with some reduction in benzodiazepine prescribing, but other improvements were not evident. Polypharmacy was identified in 63% of fallers and was strongly predictive of PIP, where the odds of PIP increased nearly 4-fold. A higher co-morbidity score significantly increased the likelihood of PIP with a linear association of comorbidity and PIP, reflecting a higher prevalence of PIP in patients with multiple comorbid conditions; thus compounding the falls risk associated with multiple comorbidities.
A high prevalence of psychotropic prescribing was also observed in our group despite a median age of 82 years: 17.5% anxiolytics, 15% antipsychotic medication, 30% hypnosedatives and 26% antidepressants. Furthermore, the incidence of new initiation of psychotropic medications increased in the 12 months post-fall. With new initiation of 15% of hypnosedatives and 9.1% of anxiolytics observed during the 12 months post-fall. Exploring the cause of this increased psychotropic prescribing post-fall was outside the scope of this study and requires further research. As falls are associated with the development of fear of falling, leading to isolation and depression this may account for this observation. Benzodiazepines are a particular issue as one of the main medication risk factors for falls and fractures in older people as a result of their negative impact on cognition, gait and balance. The pharmacodynamics of benzodiazepines alters with advancing age, as the concentration producing half of a full response (EC50) for sedation reduces by 50% with advancing age. Newer hypnosedatives such as Zolpidem, a non-benzodiazepine sedative-hypnotic also produces clinically significant balance and cognitive impairment upon awakening from sleep. The use of these newer drugs is associated with higher risks than was previously recognised. Psychotropic medication should be avoided in older patients due to the substantial increased risk of falls.
Our results compare with 36% PIP using STOPP30 criteria in the national HSE-PCRS population and 41% for the local population. Long-acting benzodiazepine prevalence rates in the over 70 s were higher in our catchment area (9%) and our study cohort (10.7%) than in population studies from Ireland (5.2%), the UK (4%) and the Netherlands (5%).
Reducing PIP in older populations will require implementation of enhanced methods to regularly assess drug effectiveness, dosage, duration, interactions and adverse symptoms. Although withdrawal of long-term benzodiazepines is challenging, due to dependency, phased discontinuation programmes and intervention strategies can be successful. Indicators for appropriate initiation of benzodiazepines prescribing may prove a more realistic method to reduce prescribing in this area. Reduction of polypharmacy is associated with a 31% reduction of falls risk. In the UK, the National Service Framework for older people recommends regular medication reviews. Patients taking four or more drugs should be reviewed every 6 months and those taking fewer medications should be reviewed annually. These standards were incorporated into the National Institute for Clinical Excellence (NICE) standards of the assessment and prevention of falls in 2004. Polypharmacy does not imply inappropriate prescribing but it is consistently associated with the risk of PIP. Reducing the number of drugs used by older people would be expected to reduce the risk of PIP and reduce direct and indirect associated costs. Information technology systems and computerised decision supports may provide the infrastructure to monitor prescribing in older patients more effectively in the future. Interventions to reduce PIP and associated falls in older populations also require closer integration between hospital, primary care and pharmacy.
Limitations
The limitations of this study include the lack of detailed diagnostic information, precluding the application of all Beers and STOPP criteria. The STOPP/Beers criteria are based exclusively on all dispensed medications; however, there may be some differences in prescribing versus dispensing, which were not captured. The database does not include over-the-counter (OTC) medications; however, it is important not to underestimate the importance of OTC medications, such as antihistamines and other sedating OTC medications, an important consideration in falls risk assessment. OTC medications can also lead to significant drug–drug interactions (e.g. ginkgo biloba and St Johns Wort with warfarin resulting in increased bleeding risks). This study is limited geographically to one large centre and to medical cardholders. Replication in other geographical sites would be important for generalisability. Data capture was dependent on the registration of a fall at the time of triage. It is possible that some cases of falls were missed. Patients with syncope and transient loss of consciousness were not specifically captured. Correlation with other risk factors for falls such as frailty, cognitive impairment, history of previous falls, cardiac arrhythmia, poor eyesight and the use of walking aids were outside the scope of this study and warrant further evaluation by prospective study.