Comparison of patient questionnaires, medical records, and plasma assays in assessing exposure to benzodiazepines in elderly subjects.

OBJECTIVE: Exposure in pharmacoepidemiologic studies can rely on various sources such as medical records, patient questionnaires, or plasma samples, which do not always concur. This study endeavored to compare sources of information on current exposure to benzodiazepines in elderly subjects. METHODS: In a study in a hospital admissions department, 1136 elderly subjects included in a case-control study each completed a structured questionnaire. In addition, an inspection of the medical records of each subject was performed, as well as screening of a plasma sample (high-pressure liquid chromatography--diode array detector) for current exposure to benzodiazepines. RESULTS: Benzodiazepines were found in the plasma of 33% of 1013 patients, in the records of 31% of patients, and in the questionnaires of 36% of 797 respondents. With use of the plasma results as a standard, questionnaires had 11% false positives and 28% false negatives; medical records had 14% false positives and 23% false negatives. The kappa for concordance between questionnaires and records was 0.63. Most of the errors were related to the unexpected presence in plasma of clorazepate, commonly used as a hypnotic agent. CONCLUSIONS: Patient recall and medical records are not reliable measures of current exposure to benzodiazepines in elderly persons, although this unreliability may be more marked with certain drugs used as hypnotic agents.

Benzodiazepines and hip fractures in elderly people: case-control study.

OBJECTIVE: To determine whether benzodiazepines are associated with an increased risk of hip fracture. DESIGN: Case-control study. PARTICIPANTS: All incident cases of hip fracture not related to traffic accidents or cancer in patients over 65 years of age. 245 cases were matched to 817 controls. SETTING: Emergency department of a university hospital. MAIN OUTCOME MEASURES: Exposure to benzodiazepines and other potential risk or protective factors or lifestyle items. RESULTS: The use of benzodiazepines as determined from questionnaires, medical records, or plasma samples at admission to hospital was not associated with an increased risk of hip fracture (odds ratio 0.9, 95% confidence interval 0.5 to 1.5). Hip fracture was, however, associated with the use of two or more benzodiazepines, as determined from questionnaires or medical records but not from plasma samples. Of the individual drugs, only lorazepam was significantly associated with an increased risk of hip fracture (1.8, 1.1 to 3.1). CONCLUSION: Except for lorazepam, the presence of benzodiazepines in plasma was not associated with an increased risk of hip fracture. The method used to ascertain exposure could influence the results of case-control studies.

Benzodiazepine use in patients hospitalized in a department of internal medicine: frequency and clinical correlates.

PURPOSE: Misuse and overuse of benzodiazepines (BZD) are common. Several studies have shown that benzodiazepines are frequently used in hospitalized patients, but fewer studies have been conducted to investigate whether BZD use increases during the hospital stay or whether patients have already taken BZD before admission. OBJECTIVE: To assess the prevalence of benzodiazepine use in hospitalized patients and to determine characteristics associated with this use. METHODS: Prospective study over a 4-month period based on all admissions to a department of internal medicine. The main outcome was the prevalence of benzodiazepine use at admission, during hospital stay and at discharge. RESULTS: Of 444 patients admitted, 147 (33%) used at least one benzodiazepine which was in 75% of the cases, short-elimination half-life BZD used as hypnotic. Of 105 (23.6%) patients using BZD at admission, 23 (5.2%) stopped BZD during hospital stay or when leaving hospital. The in-hospital prevalence of BZD use was 30% (133 patients). In 28 (6.3%) patients without BZD at baseline, BZD was introduced during the hospital stay then stopped at discharge in 18 (4%) patients. The prevalence of BZD use at discharge was 23.9% (106 patients). In multivariate analyses, BZD use was significantly associated with number of drugs taken during hospitalization (OR: 1.13; 95% CI: 1.03-1.24), and current neuropsychiatric diseases (OR: 2.12; 95% CI: 0.86-5.23), but not with gender, age or length of stay. CONCLUSION: Prevalence of BZD use appeared to be fairly high among hospitalized patients. There were very few new BZD users during hospital stay, most of whom were stopped at discharge. Most treatments were started before hospital, and continued during and after hospital stay without clear reevaluation.

Adverse drug reactions in a department of systemic diseases-oriented internal medicine: prevalence, incidence, direct costs and avoidability.

OBJECTIVE: Adverse drug reactions (ADRs) are a major cause of hospital admission and in-hospital morbidity. Departments of internal medicine are at the forefront of this problem. To increase the knowledge base, we did a study of the frequency, hazard function, avoidability, and cost of ADRs as a cause for admission in internal medicine, or when occurring after admission. METHODS: This prospective cohort study was based on all admissions to an internal medicine unit over a 4-month period. Patients were intensively followed in order to assess any ADR occurring during the hospital stay. Causality, direct costs, and preventability were assessed. RESULTS: Of 444 admissions (2569 patient-days), 156 ADRs occurred in 116 patients (26.1% of all admissions); 95 (21.4%) of these had ADRs at admission, which were the reason for admission in 32 (7.2%). Twenty-one patients (4.7%) presented with 26 ADRs during hospitalization. The in-hospital ADR incidence rate was 10.1 per 1000 patient-days. The cost of ADRs leading to hospitalization was estimated at Euro 11,357 per hospital bed per year. Eighty percent of ADRs could be considered preventable. CONCLUSION: ADRs in hospitalized patients are common and often preventable. Since most ADRs occurred before admission, prevention strategies should preferentially target primary health care providers.

Is reporting rate a good predictor of risks associated with drugs?

AIMS: Uncertainty as to relative under-reporting plagues the comparisons of spontaneous reporting rates as a tool for decision-making in pharmacovigilance. However, it is generally accepted that under-reporting should be reasonably similar for similar drugs sharing the same indication, country and period of marketing. To test this, we compared the adverse drug reaction reporting rates to the French regional pharmacovigilance centres for six pairs of identical drug marketed at the same time by different companies under different brand names (co-marketing). METHODS: All reaction reports were related to sales, to compute reporting rate; within each pair, the reporting rate ratio and its confidence interval were calculated. RESULTS: The rate ratios were all between 0.76 and 1.33. Two of them were significantly different from 1 (1.28; 95% C.I. [1.01; 1.60] and 1.33; 95% C.I. [1.06; 1.74]). CONCLUSIONS: These small differences in reporting rates would not warrant regulatory action and support the usual assumption of similar reporting for similar drugs.