Medication-related problems and psychotropic drug use in vulnerable older populations : a focus on acute hospital admissions and cognitive impairment

Abstract: The ageing process involves several physiological changes that affect both pharmacodynamics and pharmacokinetics and that, in combination with a heavier disease burden and more extensive use of medicines, put older people at higher risk of medication-related problems and associated clinical outcomes. The older population is often treated as a homogenous group, when in fact there are factors that render certain individuals more vulnerable to adverse drug effects and other types of medication-related problems. Older people encountered in the acute medical care setting and/or individuals with varying degrees of cognitive impairment are especially vulnerable in that context. The overall aim of this thesis was to describe and understand medication use in certain vulnerable subgroups of older people, which in turn might identify suitable target populations in which medication-related problems can be prevented or managed through interventions or similar efforts.Paper I presented, in the form of a study protocol, a clinical pharmacist intervention intended to reduce the risk of medication-related readmission to hospital among people aged 75 years or older during transitions of care. Based on 300 participants from the intervention study, approximately 50% had been readmitted to hospital within 180 days of being discharged from the hospital. Both heart failure and cognitive impairment, the latter identified through a four-item test, were predictors of early readmission. Altogether, the study population seems relevant for the purpose of the intervention; whether the intervention model is effective remains to be determined.Based on the same sample of study participants, paper II found that approximately one third of the 300 index hospital admissions were possibly medication related. Moreover, possibly medication-related hospital admissions were negatively associated with the fewest positive/correct answers on the four-item screening tool for cognitive impairment, which suggests that those clinical events might be less prevalent among people with cognitive impairment when exploring the association cross-sectionally. Both papers III and IV were registry-based studies, and their overall objective can be summarized as to describe psychotropic drug use and associated factors among older people with major neurocognitive disorder (NCD). Paper III focused on differences between major NCD subtypes, whereas paper IV compared people with major NCD against matched references from the total older population. In brief, overall psychotropic drug use was notably higher among people with major NCD, although generally in line with national treatment guidelines in terms of individual drugs of choice. The use of hypnotic drugs was also extensive in the reference group, and deprescribing efforts seem warranted, although longitudinal studies that focus on long-term use could provide a better picture of the potential problem. Nursing home stay was also positively associated with psychotropic drug use for all classes of psychotropic drugs, and the difference was most prominent for antipsychotic drugs. In that context, over 1,200 people in the reference population, most of them nursing home residents, had filled prescriptions for antipsychotic drugs, a figure indicating that the management of neuropsychiatric symptoms might also be an issue among older people who, due to various circumstances, have not been examined and diagnosed with neurocognitive disorders. Regarding major NCD subtypes, individuals with Lewy body dementia had, except for antidementia drugs, higher odds of psychotropic drug use than did those with Alzheimer’s disease. For example, the odds of antipsychotic drug use were more than twice as high, which is a worrying figure given that people with Lewy body dementia are extremely sensitive to the adverse effects of those specific drugs.In conclusion, this thesis illustrates the heterogeneity of demographics and drug use among older people and indicates that certain types of medication-related problems may be more relevant in certain older subpopulations. Medicines appear to be involved in many hospital admissions of older people, and the acute medical setting and subsequent care transitions are likely an important focus of pharmaceutical interventions. However, psychotropic drugs are probably not a major issue in that specific context. Efforts to reduce psychotropic drug use are likely more relevant to people with major NCD, especially in the nursing home setting. Antipsychotic drug exposure among persons with Lewy body dementia could be one such focus, especially since there are other better-balanced pharmacological treatment options for these individuals in terms of efficacy and safety profile.