Factors associated with antipsychotic drug use in residential care: changes between 1990 and 1997

Abstract

Background: There is limited information from population-based studies about the rates of antipsychotic drug use in residential and nursing homes in the UK, and associated adverse effects.

Objectives: To examine the relationship between antipsychotic drug prescription, cognitive impairment and disturbed behaviour in this population over time, and to identify possible adverse consequences of their use.

Methods: Two censuses of the residential and nursing home population aged 65 years and older in Leicestershire, carried out in 1990 and 1997. A questionnaire was completed by care staff for each resident, including information on demographic details, physical functioning, cognitive impairment, behaviour disturbance, urinary incontinence, falls, mobility, daytime alertness (1997 only), and prescribed medication.

Results: The prevalence of staff-rated moderate or severe cognitive impairment increased from 38.0% in 1990 to 44.3% in 1997. The prevalence of staff-rated disturbed behaviour decreased from 11.8% in 1990 to 10.4% in 1997. Cognitive impairment was strongly associated with disturbed behaviour in both years. The prescription rate of antipsychotic drugs increased from 17.8% in 1990 to 21.9% in 1997. There was no significant change in the prescription rates to cognitively impaired residents between 1990 and 1997 (29.1% vs 30.7%). In residents without cognitive impairment, the prescription rate rose from 10.7% to 15.0%. Antipsychotic drug use was independently associated with: younger age, type of home (1990 only), cognitive impairment, offensive behaviour, lower ADL dependency (1990 only), antidepressant drug use, reported urinary incontinence and greater mobility. There was no association with increased liability to falls or drowsiness. In the cognitively unimpaired residents, antipsychotic drug use was not associated with urinary incontinence in 1997, and there was an association with increased drowsiness in that year.

Conclusions: The only significant change in antipsychotic drug prescribing practice in this population over the period covered by this study was an increase in the prescription rate in cognitively unimpaired residents in 1997, possibly related to mental hospital closures. Urinary incontinence was the principal adverse effect of antipsychotic drug use observed in the group as a whole. Changes in the adverse effects associated with antipsychotic drug use may be a function of the increasing frailty.