Use of benzodiazepines and benzodiazepine-related drugs among 223 patients with an acute hip fracture in Finland: Comparison of benzodiazepine findings in medical records and laboratory assays

Abstract

Background and objective: CNS drugs are a risk factor for falls and fractures among older people. Our aim was to describe the use of benzodiazepines and benzodiazepine-related drugs among patients admitted to two Finnish hospitals as a result of an acute hip fracture, and to analyse the concordance of benzodiazepine findings from different data sources.

Patients and methods: We studied the use of benzodiazepines and benzodiazepine-related drugs by (i) asking the patient or his/her relatives about his/her use of hypnotics; (ii) checking the patient's medical records; and (iii) analysing for the presence of benzodiazepines in serum and urine. Blood and urine samples were taken at admission. Detection of benzodiazepines in serum and urine was achieved by the fluorescence polarisation method. Concordance in benzodiazepine findings between medical records and laboratory results was estimated by calculating the degree of agreement (kappa) and described graphically using a Venn diagram.

Results: A total of 223 patients were enrolled in the study. Of these, 71% were women. The mean age of women was 80.5 years (SD: 10) and of men, 73 years (SD: 12) [p < 0.0001]. Thirty percent of the patients reported that they used hypnotics. Benzodiazepine in serum or urine was detected in 83 (37%) patients. Over half of the patients coming from residential homes (53%) and institutions (54%) were benzodiazepine-positive. For home dwellers the proportion of patients that were benzodiazepine-positive was 29%. In 48% (40/83) of the benzodiazepine-positive patients, the type of benzodiazepine could not be identified because of a lack of drug records regarding benzodiazepines. A total of 113 (51%) patients used benzodiazepines or benzodiazepine-related drugs when both laboratory results and medical drug records were taken into account. Thirty-nine percent of these patients were home dwellers, 69% came from residential care and 76% from institutional care. The concordance between medical records and laboratory results expressed as overlap area was 32% in men and 59% in women, 38% in community-dwelling patients, 63% in residential home patients, and 68% in patients from institutions.

Conclusion: Half of patients with an acute hip fracture used benzodiazepines or benzodiazepine-related drugs. The highest prevalences were found in institutional and residential care where it should be well known that the use of CNS drugs increases the risk of hip fracture. Concordance of benzodiazepine findings was moderate in all patients and poorest among men. Concordance was poorer among home dwellers than among those living in residential homes and institutions. Analysing benzodiazepine in serum seems to be the most reliable method for ascertaining benzodiazepine exposure. This laboratory test could be performed routinely when the elderly patient is admitted to hospital because of a fall or, at least, in case of hip fracture. Then, if needed, the patient should be informed about the risks of benzodiazepine use, and further falls and fractures could be prevented.