Читать книгу Pathy's Principles and Practice of Geriatric Medicine - Группа авторов - Страница 308

The geriatric syndromes, which could be considered preventable adverse events if they arise de novo in older people in the hospital and are not related solely to the progression of disease:

 Functional decline

 Loss of mobility

 Urinary or faecal incontinence

 Delirium

 Severe constipation

 Pressure sores

 Falls

 Malnutrition and/or dehydration

 Depression

Other common adverse events in older people:

 Hospital‐acquired infection (in older patients, notably aspiration pneumonia and catheter‐associated infections)

 Adverse drug events

 Venous thromboembolism

 Procedure‐related complications

As with other adverse events in the hospital, at first glance, the incidence of adverse drug events seems to increase with age, but there is some evidence that they are directly related to complexity and comorbidity rather than age alone. Recent studies have estimated the incidence of adverse drug events in older people in the hospital to be between 31.9 and 37%.³⁴ As with all estimates of hospital‐associated risks, this figure depends very much on the definitions and methodologies used. Nevertheless, even when relatively strict definitions are used, adverse drug events are the most common adverse events to affect hospitalized patients of all ages.³⁵

People over 60 are the highest users of medications, receiving 59% of dispensed prescriptions in the UK.³⁶ Polypharmacy is an important issue – one‐fifth of people age 70 years take five or more medications.³⁷ Virtually all older patients who are admitted to the hospital are given drug treatment of some description. It would be unusual for an older patient not to have been taking any medications prior to admission or for these not to have changed in some way by the time of discharge.

Adverse drug events are also a significant cause of hospital admission in older people (estimated at 6.5% of admissions, with a median length of stay of 8 days³⁸). Furthermore, patients admitted because of an adverse drug event have a significant chance (17.7%³⁹) of subsequent readmission due to further adverse drug events. Box 11.2 shows the common types of medication‐related problems that may occur at different stages of the hospital admission process in an older person.

Outside the hospital, the highest users of medications are care home residents. A recent study in the UK showed that the incidence of medication errors in nursing home residents was as high as 69.5%.⁴⁰ The categories of error found were similar to those in Box 11.2 – they included prescribing, monitoring, dispensing, and administration errors. The underlying causes of the errors in both hospitals and care homes relate to common underlying patient safety themes: system failures, individual errors, communication problems within and between healthcare teams and the patient, and assessment or diagnostic skills and procedures not tailored to the individual.

Certain categories of drugs are more problematic than others for older people, notably anticoagulants, opiates, and other centrally acting medications. Several efforts have been made to identify groups of medications that pose a particular risk so that they can be more easily avoided in this population, such as those categories of drugs included in the Beers criteria.⁴¹ The fact that common treatments such as oxygen and intravenous fluids should be treated the same way as other drugs is sometimes forgotten, but these are potentially dangerous treatments (particularly for older patients) and should be administered with due caution. The physiological changes associated with normal ageing and the pathological changes associated with disease processes common among older people in the hospital all impact the risks associated with giving medications to this population. These changes have effects on the pharmacokinetics and pharmacodynamics of virtually all medications.

Frail elderly people are rarely included in large pharmaceutical trials, which in turn may result in harm because findings from clinical trials involving younger patients may be incorrectly extrapolated to older patients. The changes that occur with age also have practical implications in terms of drug regimens, administration, and concordance; for example, swallowing difficulties, arthritis, and cognitive or visual impairment need to be taken into consideration when prescribing and administering drugs to these complex patients.

As with all patient‐safety issues in older people, adverse drug events do not occur in isolation – they are closely linked to the geriatric syndromes in both cause and effect. The unique characteristics of the frail elderly again play a part here. Because of the frequently nonspecific ways in which adverse drug events present in these patients (often in the form of the geriatric syndromes described above, particularly delirium or falls), they often go unrecognized — and rather than the causative agents being stopped, more medications are added, causing further adverse effects. This can lead to a vicious circle known as the prescribing cascade.⁴²