This expert consensus should provide prescribers with an epidemiological tool, a guideline and a list of alternative therapies.

What is already known about this subject • Several studies have shown that inappropriate medications induce adverse health outcomes in the elderly. • The hypothesis of Beers et al. that these inappropriate medications increase the likelihood of adverse drug reactions is debated and checked in patients admitted to hospital. What this study adds • Inappropriate medications do not seem to be the major cause of adverse drug reactions in the elderly. • More than the inappropriateness of the drugs themselves, it is the inappropriate use of drugs that is to be tackled when treating the elderly. • The main preventable factor is the reduction in the number of drugs given. Aim To study the occurrence of adverse drug reactions (ADRs) linked to inappropriate medication (IM) use in elderly people admitted to an acute medical geriatric unit. Methods All the elderly people aged ≥ 70 years admitted to the acute medical geriatric unit of Limoges University hospital (France) over a 49‐month period were included, whatever their medical condition. For all the patients, clinical pharmacologists listed the medications given before admission and identified the possible ADRs. The appropriateness of these medications and the causal relationship between drugs (either appropriate or not) and ADRs were evaluated. Results Two thousand and eighteen patients were included. The number of drugs taken was 7.3 ± 3.0 in the patients with ADRs and 6.0 ± 3.0 in those without ADRs (P < 0.0001). Sixty‐six percent of the patients were given at least one IM prior to admission. ADR prevalence was 20.4% among the 1331 patients using IMs and 16.4% among those using only appropriate drugs (P < 0.03). In only 79 of the 1331 IM users (5.9%) were ADRs directly attributable to IMs. The IMs most often involved in patients with ADRs were: anticholinergic antidepressants, cerebral vasodilators, long‐acting benzodiazepines and concomitant use of two or more psychotropic drugs from the same therapeutic class. Using multivariate analysis, after adjusting for confounding factors, IM use was not associated with a significant increased risk of ADRs (odds ratio 1.0, 95% confidence interval 0.8, 1.3). Conclusion Besides a reduction in the number of drugs given to the elderly, a good prescription should involve a reduction in the proportion of IMs and should take into consideration the frailty of these patients.

Hospitalisation in geriatric services results in a reduction in potentially inappropriate medication use. Improved pharmacological education of practitioners, especially with regard to drug adverse effects, is desirable to improve management of geriatric patients.

The size of the elderly population has been increasing steadily for several years. Individuals in this age group often have several concomitant diseases that require treatment with multiple medications. These drugs, for various reasons and especially as a consequence of potential accumulation, may be associated with adverse reactions. Of the numerous factors that can favour the occurrence of these adverse drug reactions, the most important are the pathophysiological consequences of aging, particularly as these apply to the very old. Although absorption of drugs is not usually reduced in the elderly, diffusion, distribution and particularly elimination decline with age. Furthermore, while hepatic metabolic function is fairly normal, renal function is usually markedly depressed in very old individuals, and this can translate into clinical consequences if it is not taken into account. This is why, before administration of any drug in the elderly, evaluation of glomerular filtration rate is essential. Validated estimations such as those obtained from the classical Cockcroft-Gault formula or from more recent methodologies are required. In addition to reductions in various organ functions, factors connected with very old age such as frailty, falls, abnormal sensitivity to medications and polypathology, all of which tend to be more common in the last years of life, all directly impact on adverse drug reaction occurrence. Given these characteristics of the elderly population, the best way to reduce the prevalence of adverse drug reactions in this group is to limit drug prescription to essential medications, make sure that use of prescribed agents is clearly explained to the patient, give drugs for as short a period as possible, and periodically re-evaluate all use of drugs in the elderly.

Paraoxonase 1 (PON1), an A-esterase with peroxidase-like activity present on the surface of HDL, decreases the peroxidation of LDL. Serum PON1 activity (PON1a) decreases with aging and in disorders associated with a high risk of adverse cardiovascular events (acute myocardial infarction, diabetes mellitus, and chronic renal failure). The implication of vascular factors in Alzheimer-type dementia (ATD) is strongly suspected. We measured PON1a by spectrophotometry using the paraoxon substrate in 180 healthy subjects (controls; mean age: 75.3 +/- 8.9 years; 98 women) and 154 patients admitted for cognitive testing. According to criteria, 45 patients had mild cognitive impairments (MCI; mean age: 75.6 +/- 9.3 years; 28 women), 60 had ATD (mean age: 75.6 +/- 8.3 years; 47 women), and 49 had vascular dementia (VaD; mean age: 77.5 +/- 7.2 years; 33 women). Mean PON1a was lower in VaD (0.25 +/- 0.1 U/mL) than in controls or ATD (both 0.41 +/- 0.2 U/mL, p < 0.01). Mean PON1a values in MCI (0.34 +/- 0.2 U/mL) and ATD (0.41 +/- 0.2 U/mL) were not significantly different. In multiple linear regression, PON1a was negatively correlated with male sex, age, and VaD, and positively correlated with ATD (each correlation p < 0.001). As shown in other high-risk cardiovascular disorders, PON1a seems to be a reliable marker of VaD. Its modification in Alzheimer's disease supports the implication of vascular risk factors in this type of dementia.