Polypharmacy in geriatric patients: too little or too much?

Abstract

This thesis deals with accidents happening in usual care regarding medication use. The evaluation of polypharmacy during geriatric assessment is described. Finally, the di-lemmas in the treatment of frequently present cardiovas-cular diseases are discussed. In chapter 1.1 a case report is presented about dirt in a fax machine causing a grey stripe on a faxed prescription of trazodone. This obliterated part of the prescription, lead-ing to an instruction label with a fourfold increase of the daily dose resulting in an anxious patient with dementia collapsing after the first dose. In chapter 1.2 it is described how a patient becomes intoxicated with valproic acid due to accidental over-dosing after a transfer from a nursing home. The cause was an incorrect combination of the amount and concentration of valproic acid prescribed, proba-bly because accidentally the wrong solution was marked during electronic prescribing. Chapter 1.3 describes a prospective study about discrep-ancies in the drug use of geriatric outpatients as reported by the patient and their caregivers, the GP and the phar-macy. Included were 120 patients. In 90 patients there was at least one discrepancy between the medication reported by the patient and the GP(75%). Twenty-nine patients (24.2%) ex-perienced possible medication discrepancy adverse pa-tient events. In chapter 2.1 the effects of admission to a geriatric ward on medication use are retrospectively analysed. A com-parison is made between the 724 patients admitted in 1985 versus the 258 patients admitted during 2002. The main difference shown between drug use before and after admission, was an increase in the amount of drugs used, especially because of the prescription of vitamins. Chapter 2.2 describes that medications were frequently discontinued because the diagnosis was no longer rele-vant (39% of discontinued medication), adverse events (33%) and better pharmacotherapeutical options (22%). Since also frequently medications were added because of new diagnoses (69.2%), osteoporosis prophylaxis (15%) and improvements in pharmacotherapy (10.6%), after geriatric assessment patients used a higher mean number of drugs (4.6 before CGA versus 5.4 after CGA). Chapter 2.3 describes the prevalence of under-treatment in geriatric outpatients. Before CGA, 170 patients were undertreated (32.9%), after CGA 115 (22.3%). Contraindications were present in 102 of the patients(19.8%) and more frequent in undertreated pa-tients. Correction of all under-treatment regardless of the presence of contraindications would have increased the number of drugs with 97 used to a mean of 6.8 drugs in the whole population, and to 7.5 in the population still un-dertreated after CGA. In chapter 2.4 the prevalence and clinical relevance of drug-drug interactions (DDIs) in the 807 geriatric outpa-tients visiting the day clinic in 2004 are described. In 300 patients, 44,5% of patients using more than one drug, 398 potential DDIs were identified. In 172 patients,25,5% of all patients using more than one drug, drug combinations were found with either adverse drug reactions possibly due to combinations of culprit drugs or inadequate reac-tion to therapy. A prospective exploratory pilot study is described in chapter 2.5. After CGA, 40 patients and their caretakers were questioned and if necessary visited at home to as-sess whether changes in medication advised after CGA were reported to be followed. The medication use was adjusted completely as the geriatricians had prescribed in 77.5 % of the patients. Of the changes in medication ad-vised after CGA, 90% were reported to be followed. Only the presence of a caretaker who checked medication use was associated with complete adherence to drug therapy. In chapter 3.1 the treatment of hypertension in geriatric outpatients, 80 years or older, is described and compared with the patients included in the landmark HYVET trial. During 2004, 141 of the 147 patients in this age group with hypertension in the history were treated with antihyperten-sive medication (95.9%). Of these patients, 52 (35.4 %) would have been eligible for HYVET, 95 patients (64.6%) would have been excluded . The 147 geriatric patients included in our study showed more co-morbidity than the HYVET population e.g. dementia, strokes and cardiovas-cular disorders besides hypertension. Adequate blood pressure control defined as the target pressures of HYVET, was seen in 50.3 % of the patients. The patients who would have been excluded from HYVET had similar levels of blood pressure control as the patients who would have been included. The only significant difference be-tween the patients who showed an adequately controlled blood pressure and those who did not was the mean num-ber of antihypertensive medications: 2.2 ( 1.0) versus 1.8 ( 1.1) respectively. In chapter 3.2 the contraindications for anticoagulation in elderly patients with atrial fibrillation are reviewed. It is de-scribed how higher age is associated with under-treatment. Patients with a higher risk of stroke also show higher rates of bleeding complications. The bleeding risk in usual care is higher than in trials. Published bleeding rates reflect selection bias, describing mainly relatively healthy elderly patients. The use of stratification schemes for stroke risk and for bleeding risk will have to be implemented. In chapter 3.3 it is shown that in geriatric outpatients with atrial fibrillation, risk factors for stroke favouring the use of anticoagulants and contraindications to cumarins fre-quently coexist in the same patients. After CGA, 73 (52%) of the 141 patients with continuing chronic or paroxysmal AF were continued on cumarins. Extra risk factors sup-porting the use of warfarin, as well as contraindications to the use of cumarins were present in 110 patients (78.0%). Neither the presence of risk factors or the presence of contraindications was associated with cumarin use. Only increasing age was significantly associated with the chance not to be prescribed anticoagulants.