Use of nonsteroidal anti-inflammatory drugs and risk of fractures

In animal models, prostaglandin synthesis has been found to mediate bone metabolism. Nonsteroidal anti-inflammatory drugs (NSAIDs), given their inhibitory effects of prostaglandin synthesis, may play a role in the prevention of osteoporosis. The primary objective of this study is to describe and quantify the fracture risks of patients exposed to NSAIDs in a representative general medical practice setting. A retrospective cohort study was conducted in a general medical practice setting in the UK (using data from the General Practice Research Database). Regular NSAID users (who received three or more NSAID prescriptions), aged 18 years or older, were compared with matched control patients and incidental NSAID users. The study comprised 214,577 regular NSAID users, 286,850 incidental NSAID users, and 214,577 control patients. The relative rate of nonvertebral fractures during regular NSAID treatment compared with control was 1.47 (95% confidence interval [CI] 1.42-1. 52) and that of hip fracture 1.08 (0.98-1.19). No differences in nonvertebral fractures were found between the regular and incidental NSAID users (RR = 1.04; 95% CI 0.99-1.09). The rate of nonvertebral fractures among users of diclofenac (RR = 1.00; 95% CI 0.93-1.08) and naproxen (RR = 0.91; 95% CI 0.82-1.00) was similar to that of ibuprofen. The results of this study are not supportive of clinically significant effects of NSAIDs on bone metabolism.

Use of sympathomimetic drugs leads to increased risk of hospitalization for arrhythmias in patients with congestive heart failure

BACKGROUND

Sympathomimetic agents have a direct positive chronotropic effect on heart rate and may cause hypokalemia, even when administered by inhalation. In selected patients (e.g., patients with congestive heart failure [CHF]) this can lead to arrhythmias. Despite the potential adverse effects of these agents, they are used frequently in patients with CHF, due to a high incidence of respiratory comorbidity. This study investigates the effects of sympathomimetics on the incidence of hospitalizations for arrhythmias in patients with CHF.

METHODS

In a cohort of 1208 patients with a validated hospital discharge diagnosis of CHF, we identified 149 cases with a readmission for arrhythmias, and compared these in a nested matched case-control design with 149 controls from the remainder of the cohort with no hospital readmission for any cardiac cause. Conditional logistic regression was used to calculate the risk for hospitalization for arrhythmias associated with exposure to sympathomimetic agents, expressed as odds ratios.

RESULTS

Of 149 case patients, a total of 33 (22.1%) were treated with any sympathomimetic agent, and 6 patients (4.0%) were treated with systemic sympathomimetics. The use of any sympathomimetic drug was associated with an increased risk of admission for arrhythmia (odds ratio, 4.0; 95% confidence interval, 1.0-15.1). For systemic sympathomimetic drugs, the corresponding odds ratio was 15.7 (95% confidence interval, 1.1-228.0).

CONCLUSIONS

The results of this study strongly suggest an increased risk of hospitalization for arrhythmias in patients with CHF treated with sympathomimetic drugs. Sympathomimetics should be given under close surveillance to patients with CHF.

Long-term oral contraceptive use increases breast cancer risk in women over 55 years of age: the DOM cohort

The role of past oral contraceptive use in the development of breast cancer is unclear, particularly in postmenopausal women. The authors investigated this relationship among pre- and postmenopausal middle-aged women in a nested case-control study within the population-based DOM cohort, Utrecht, the Netherlands. Among a total population of 12,184 women followed up for an average of 7.5 years, 309 breast cancer cases aged 42 to 63 years, diagnosed from November 1982 through May 1996, and 610 controls were examined. Overall, duration of oral contraceptive use was not clearly related to breast cancer. In women older than 55 years, however, oral contraceptive use for more than 10 years was associated with a 2-fold increased risk of breast cancer (odds ratio (OR) 2.1, 95% confidence interval (CI) 1.1-4.0). We conclude that long duration of oral contraceptive use increases the risk of breast cancer in women over 55 years of age but not in younger women.

Differences in attitudes, knowledge and use of economic evaluations in decision-making in The Netherlands. The Dutch results from the EUROMET Project

OBJECTIVE

To investigate differences in attitudes, knowledge and actual use of economic evaluations in different groups of decision-makers, and to compare the results from the Netherlands with the overall European results of the European Network on Methodology and Application of Economic Evaluation Techniques (EUROMET) project.

DESIGN AND SETTING

Members of the EUROMET group conducted interviews and surveys with politicians, regulators, hospital pharmacists and physicians in The Netherlands. Three approaches of investigation could be adopted: (i) a postal questionnaire survey, (ii) semi-structured interviews, and (iii) a focus-group approach.

MAIN OUTCOME MEASURES AND RESULTS

In the Netherlands, decision-makers generally have a positive attitude towards economic evaluations. Nevertheless, their actual use and knowledge of economic evaluations are still limited. Hospital pharmacists and regulators are more objective than physicians and politicians, who also base their judgements on other societal values. Hospital pharmacists and regulators have a greater knowledge of economic evaluations, and they use them more often than the other groups. Most decision-makers do not want to base their decisions strictly on a cost-effectiveness ranking alone. Our findings were similar to the findings in other European countries.

CONCLUSIONS

Decision-makers prefer to make their own broad comparisons of advantages and disadvantages, and do not base their decisions solely on a single summary measure.

Cyclical etidronate use is not associated with symptoms of peptic ulcer disease

OBJECTIVE

To investigate whether the alkylbisphosphonate etidronate is associated with an increased risk of gastrointestinal symptoms.

METHODS

We conducted an observational follow-up study on a possible relationship between etidronate use and the risk of gastrointestinal symptoms in a cohort of 2754 women over 50 years of age. The study was performed with data on drug prescriptions obtained from the PHARMO database in the Netherlands. Women were included when they used either cyclical etidronate (n = 1050) or estrogen (n = 1704) for at least 14 days. They were followed-up for incident use of antiulcer drugs while on exposure medication.

RESULTS

The mean ages were 72 years and 59 years in the etidronate and estrogen groups, respectively. In total, there were 95 women with incident prescriptions for gastrointestinal events after a median duration of follow-up of 2.7 months (range 0.1-19.4 months). The crude relative risk of a gastrointestinal event for etidronate compared with estrogen use was 1.2 [95% confidence interval (95% CI) 0.8-1.8]. Adjusted for baseline age, use of corticosteroids, salicylates and nonsteroidal anti-inflammatory drugs, the relative risk reversed to 0.6 (95% CI 0.4-1.2).

CONCLUSION

The use of cyclical etidronate is not associated with an elevated risk of symptoms of peptic ulcer disease.

Characteristics of current benzodiazepine users as indicators of differences in physical and mental health

The relationship between characteristics of benzodiazepine exposure and health-status was examined in order to investigate risk profiles of benzodiazepine users. In the only pharmacy of a Dutch community of 13,500 inhabitants, all current benzodiazepine users that presented with a benzodiazepine prescription in November 1994 were invited to participate. On the basis of the RAND-36 questionnaire, summary scores for both physical and mental health were calculated, the Physical Component Summary (PCS) and the Mental Component Summary (MCS). After dichotomization with a cut-off point indicating seriously impaired health and after the combination of the PCS and MCS, four different categories of health status could be identified. We used logistic regression to study the relation between these four different groups with respect to benzodiazepine exposure. In total a group of 360 current benzodiazepine users was studied. Results showed that almost one-third of the participants had no significant impaired health; this group was further classified as reference group. We classified three other groups: one with physical problems (31%), one with mental problems (18%), and one with a combination of the two (22%). Multivariate analysis showed differences in risk factors for an impaired health status. The group with impaired physical health was associated with self-reported indication for muscle relaxation, hypnotic use, and a high CDS (Chronic Disease Score). The group with impaired mental health was associated with more frequent consulting of a mental health care specialist and with a low sense of self-efficacy. The group with both impaired physical as well as mental health was associated with a higher incidence of widowhood, a lower sense of self-efficacy, a high CDS, using benzodiazepines more than prescribed, and reporting depression as reason for their benzodiazepine use. In particular, two groups need critical examination: a group of apparently healthy users with long-term benzodiazepine use; and a frail group with impaired physical and mental health and using a higher dose than prescribed. Patient counseling and management of these four groups can be tailored to the specific needs of each group.

Selective prescribing of spasmolytics

BACKGROUND

Daily clinical practice often differs largely from the clinical trial setting, so extrapolation of outcomes from trial data, such as safety, effectiveness, and economic outcomes, can be deceptive. Prescribers may intend to treat a selected group of patients with new drugs; this practice could result in significant bias in assessing outcomes of these agents during their use in daily clinical practice.

OBJECTIVE

To evaluate what type of patient received tolterodine compared with the spasmolytic drugs previously marketed (oxybutynin, flavoxate, emepronium).

DESIGN

An observational, follow-up study.

SETTING

Eighteen collaborating community pharmacies.

PATIENTS

Aged > or = 18 years, noninstitutionalized; initial therapy with tolterodine, oxybutynin, flavoxate, or emepronium.

RESULTS

Tolterodine was often used as a second-line and even as a third-line treatment, and was prescribed to a "polluted" population in terms of concomitant psychotropic medication. Tolterodine users were 7.5 times more likely to have received another spasmolytic drug (RR 7.5, 95% CI 4.8 to 11.9). In addition, these patients more frequently used antiparkinsonian drugs (RR 4.1, 95% CI 1.6 to 10.4) as well as antipsychotic drugs (RR 2.9, 95% CI 1.4 to 6.2). There was a small difference in concomitant use of antidepressants and benzodiazepines between patients receiving tolterodine versus those taking other spasmolytic drugs.

CONCLUSIONS

Tolterodine is prescribed for a population differing from that receiving previously marketed spasmolytic drugs. Selective prescribing should recognized when evaluating new drugs in daily clinical practice. Policy makers, such as pharmacy and therapeutics committees, should consider this aspect in their formulary decisions since selective prescribing can lead to unjustified conclusions about a drug's therapeutic effects (e.g., efficacy, safety, cost-effectiveness).

Use of oral corticosteroids and risk of fractures

Treatment with oral corticosteroids is known to decrease bone density but there are few data on the attendant risk of fracture and on the reversibility of this risk after cessation of therapy. A retrospective cohort study was conducted in a general medical practice setting in the United Kingdom (using data from the General Practice Research Database [GPRD]). For each oral corticosteroid user aged 18 years or older, a control patient was selected randomly, who was matched by age, sex, and medical practice. The study comprised 244,235 oral corticosteroid users and 244,235 controls. The average age was 57.1 years in the oral corticosteroid cohort and 56.9 years in the control cohort. In both cohorts 58.6% were female. The most frequent indication for treatment was respiratory disease (40%). The relative rate of nonvertebral fracture during oral corticosteroid treatment was 1.33 (95% confidence interval [CI], 1.29-1.38), that of hip fracture 1.61 (1.47-1.76), that of forearm fracture 1.09 (1.01-1.17), and that of vertebral fracture 2.60 (2.31-2.92). A dose dependence of fracture risk was observed. With a standardized daily dose of less than 2.5 mg prednisolone, hip fracture risk was 0.99 (0.82-1.20) relative to control, rising to 1.77 (1.55-2.02) at daily doses of 2.5-7.5 mg, and 2.27 (1.94-2.66) at doses of 7.5 mg or greater. For vertebral fracture, the relative rates were 1.55 (1.20-2.01), 2.59 (2.16-3.10), and 5.18 (4.25-6.31), respectively. All fracture risks declined toward baseline rapidly after cessation of oral corticosteroid treatment. These results quantify the increased fracture risk during oral corticosteroid therapy, with greater effects on the hip and spine than forearm. They also suggest a rapid offset of this increased fracture risk on cessation of therapy, which has implications for the use of preventative agents against bone loss in patients at highest risk.

Risk factors for the development of adverse drug events in hospitalized patients

Adverse drug events in hospitalized patients lead to increased morbidity, mortality and costs. Early detection of adverse drug events could aid in the prevention of these adverse outcomes. A cost-effective system for the early detection of adverse drug events should focus on high risk patients. A study was set up with the primary aim to identify characteristics that are associated with the development of adverse drug events (ADEs) in hospitalized patients. ADE reports were gathered from physicians and nurses (spontaneous reports) and from patients after intensive ward interviews by hospital pharmacists. All patients admitted to the internal medicine wards of two Dutch hospitals, during a two month period, were included. The following characteristics were analyzed for their potential relationship to the occurrence of ADEs: age (categorized), gender, number of drugs prescribed during hospital stay, types of drugs used and changes in drug use on admission. Age was found to be inversely associated with the development of ADEs (OR 0.36, CI 0.21-0.61 for age category > 80 years; OR 0.56; CI 0.31-1.02 for age category 75-80 years and OR 0.69; CI 0.42-1.11 for age category 60-74 years). Furthermore, statistically significant associations were found for the number of drugs prescribed per hospitalized patient (for the class of 4-6 drugs per patient OR 2.61, CI 1.32-5.18), for newly prescribed drugs (OR 6.65, CI 2.63-16.81) and for the cessation of drugs on hospital admission (OR 1.50, CI 1.02-2.20). The use of gastrointestinal drugs (OR 2.13, CI 1.32-3.45), central nervous system drugs (OR 1.66, CI 1.07-2.57) and antibiotics (OR 2.44, CI 1.65-3.60) were associated with the development of ADEs, when compared to all other drugs taken by the patients. In this study, the most important risk factors are the number of drugs used per patient and the starting of a new drug during hospitalization. As most hospitalized patients start new drug therapies while in hospital, this seems an inappropriate focus. However, careful monitoring of patients using more than 7 drugs at a time may be possible in a cost-effective system for the early detection of ADEs.

Use of oral corticosteroids in the United Kingdom

Administration of oral corticosteroids is associated with the development of osteoporosis and an increased risk of fractures. However, the size of the treated sub-population who would benefit from preventive therapy remains uncertain. The objective of this study was to investigate the usage pattern of oral corticosteroids in a large sample representative of the general population in England and Wales. Information was obtained from the General Practice Research Database (GPRD) which contains medical records of general practitioners. Oral corticosteroid users were patients aged 18 years or older who received one or more prescriptions for oral corticosteroids. Over 1.6 million oral corticosteroid prescriptions were issued to the cohort of 244 235 oral corticosteroid users. At any point in time, oral corticosteroids were being used by 0.9% of the total adult GPRD population. The highest use (2.5%) was by people between 70 and 79 years of age. Respiratory disease was the most frequently recorded indication for oral corticosteroid treatment (40%). Patients with arthropathies were most likely to use long-term, continuous treatment, and patients with chronic obstructive pulmonary disease least likely (19.3% and 6.1%, respectively, used oral corticosteroids for more than 2 years). The overall use of bone-active medication (oestrogens, bisphosphonates, vitamin D, and calcitonin) during oral corticosteroid treatment was low (between 4.0% and 5.5%). The current population in the UK at risk of developing corticosteroid-induced fractures might be as large as 350 000. Identification of these patients will be important for implementing preventive strategies in a cost-effective manner.

Control of blood pressure and risk of stroke among pharmacologically treated hypertensive patients

BACKGROUND AND PURPOSE

Despite improved control of blood pressure during the last decades in the United States, a considerable proportion of treated hypertensives have not achieved target blood pressure levels. We estimated the proportion of strokes occurring among treated hypertensive patients that may be attributable to uncontrolled blood pressure.

METHODS

A population-based case-control study was conducted among treated hypertensive members of Group Health Cooperative of Puget Sound. Cases were treated hypertensive patients who sustained a first fatal or nonfatal, ischemic (n=460) or hemorrhagic (n=95) stroke during 1989-1996. Controls were a random sample of stroke-free, treated hypertensive Group Health Cooperative enrollees (n=2966), similar in age to the stroke cases. Multiple measurements of blood pressure and other cardiovascular risk factors were collected from medical records. Logistic regression was used to estimate the risk of ischemic stroke and hemorrhagic stroke associated with uncontrolled blood pressure, defined as diastolic blood pressure >90 mm Hg or systolic blood pressure >140 mm Hg. The fraction of strokes attributable to uncontrolled blood pressure among treated hypertensives was calculated.

RESULTS

Blood pressure was uncontrolled in 78% of ischemic stroke cases, 85% of hemorrhagic stroke cases, and 65% of controls. After adjustment for potential confounders, uncontrolled blood pressure among treated hypertensive patients was moderately associated with ischemic stroke (risk ratio=1.5 [95% CI, 1.2 to 1. 9]) and strongly related to hemorrhagic stroke (risk ratio=3.0 [95% CI, 1.7 to 5.4]). We estimated that 27% (95% CI, 11% to 39%) of the ischemic strokes and 57% (95% CI, 26% to 75%) of the hemorrhagic strokes among treated hypertensive patients were attributable to uncontrolled blood pressure. Overall, 32% (95% CI, 14% to 45%) of all strokes were attributable to uncontrolled blood pressure.

CONCLUSIONS

A considerable proportion of incident strokes among treated hypertensive patients may be prevented by achieving control of blood pressure.

[Clinical researchers and pharmaceutical industry. The examples of troglitazone and mibefradil]

A newly introduced drug may find many obstacles in its path. The intensity of marketing of new drugs can have unwanted effects. When new drugs are prescribed for a population that differs widely from that in clinical trials, unforeseen side effects can occur. The examples of troglitazone and mibefradil illustrate these mechanisms. It is the responsibility of the drug manufacturers and prescribers to let new drugs gradually find their therapeutic position. Otherwise exaggeration of untoward effects may lead to the speedy and possibly premature withdrawal of the drugs.

Benzodiazepine pathways in the chronically ill

The association between patterns of use of benzodiazepines and chronic somatic morbidity was examined by applying the Chronic Disease Score (CDS). In the only pharmacy in a Dutch community, 6921 patients with data available covering a 10-year period (1983-1992) were included. In 1992, two-thirds of the patients had a CDS of 0, indicating no chronic morbidity. Patients with chronic morbidity showed a twofold risk of a history of benzodiazepine use. Within the group of benzodiazepine users, longer exposure to benzodiazepines as well as a history of different benzodiazepines were associated with a higher risk of chronic morbidity. Duration of episodes of use and daily dose were not found to be significantly associated with chronic disease. A pattern of increased benzodiazepine use showed a higher risk of chronic morbidity compared with benzodiazepine users with a stable use. Moreover, a history of benzodiazepine use was found to predict a sharp increase in chronic morbidity. We found a clear association between previous and actual use of benzodiazepines and chronic somatic disease. Benzodiazepine use may be induced by sleeping difficulties and anxiety problems caused by the chronic disease.

Venous thromboembolism among new users of different oral contraceptives

New use of third generation oral contraceptives is associated with a four-fold increased risk of venous thromboembolism compared with users of second generation oral contraceptives, particularly among young, healthy women.

Neighbourhood characteristics and use of benzodiazepines in The Netherlands

This paper analyses the relationship between individual and neighbourhood characteristics and the use of benzodiazepines within a Dutch city. It is hypothesized that the proportion of users is lower in more socially integrated and less deprived neighbourhoods. Hypotheses have been tested by using multi-level analysis to distinguish between composition and context effects. Age and gender have a clear relation to the use of benzodiazepines and neighbourhood differences in the proportion of users are partly the effect of population composition by age and gender. The proportion of users is higher in neighbourhoods with a higher percentage of one-parent families, with a lower percentage of social rented housing and with a larger number of rooms per person. The strength of the relation between age and use is influenced by neighbourhood characteristics. Neighbourhood variation in the amount used only depends on population composition.

Asthma exacerbations during first therapy with long acting beta 2-agonists

Long-acting beta 2-agonists (LBA) have become an important therapeutic strategy in the treatment of asthma. There is, however, debate whether LBA increase the risk of asthma exacerbations (AE). We studied whether the risk of AE was increased in patients starting LBA therapy and whether the risk was associated with severity. Patients, aged 5-49 years, who were firstly prescribed LBA between 1992 and 1995, and who had at least two consecutive prescriptions of LBA, were selected from the PHARMO-RLS database. The exposure period was the interval between the first and last dispensing of the first exposure episode. The year before the onset was the control period. Single short courses of oral glucocorticosteroids or antibiotics were used as proxy indicators for AE. Severity indicators, assessed in the 6 months before initiation of LBA, were used to classify patients' severity. A total of 788 patients met the inclusion criteria (men: 45.1%, median age: 35). The incidence rate of AE increased significantly (p < 0.001) with severity from 1.7 to 2.4 and 1.1 to 2.7 AE per person year in index and control period, respectively. The risk was merely elevated among patients who start LBA therapy without being treated with other anti-asthma drugs before (RR 1.4, 95% CI 1.0-2.2). First starters of LBA showed no overall change in incidence of AE when compared with the year before starting treatment. A total of 6.9% of patients used LBA as step-one therapy. These patients suffer, in contrast to the whole population, a 40% increased risk of having AE. Although this could be due to confounding, we recommend being reluctant to prescribe LBA to patients who have not been treated before with other anti-asthma drugs.

Signalling possible drug-drug interactions in a spontaneous reporting system: delay of withdrawal bleeding during concomitant use of oral contraceptives and itraconazole

AIMS

In spontaneous adverse drug reaction reporting systems, there is a growing need for methods facilitating the automated detection of signals concerning possible adverse drug reactions. In addition, special attention is needed for the detection of adverse drug reactions resulting from possible drug-drug interactions. We describe a method for detecting possible drug-drug interactions using logistic regression analysis to calculate ADR reporting odds ratios.

METHODS

To illustrate this method, we analysed the adverse drug reaction 'delayed withdrawal bleeding' resulting from a possible interaction between itraconazole and oral contraceptives in reports received by the Netherlands Pharmacovigilance Foundation LAREB between 1991 and 1998.

RESULTS

In total 5,503 reports were included in the study. The odds ratio, adjusted for year of reporting, age and source of the reports, for a delayed withdrawal bleeding in women who used both drugs concomitantly compared with women who used neither oral contraceptives, nor itraconazole, was 85 (95% CI: 32-230).

CONCLUSIONS

Since spontaneous reporting systems can only generate signals concerning possible relationships, this association needs to be analysed by other methods in more detail in order to determine the real strength of the relationship. This approach might be a promising tool for the development of procedures for automated detection of possible drug-drug interactions in spontaneous reporting systems.

Women with angina pectoris receive less antiplatelet treatment than men

In a study investigating the prevalence of underprescription of platelet therapy for women with angina pectoris, the complete medication histories of patients were examined and indicators of possible comorbidity and comedication were recorded. A higher percentage of women than men were not treated with any form of antithrombotic treatment (37% versus 18%), suggesting a serious, and possibly hazardous, undertreatment with acetylsalicylic acid (ASA) in women compared with men.

Adverse drug events in hospitalized patients. A comparison of doctors, nurses and patients as sources of reports

OBJECTIVE

This study investigated the relative value of adverse drug events reported by doctors, nurses and patients.

METHODS

The study was conducted on a total of four wards: the paediatric and internal medicine wards (including geriatric patients) of two peripheral hospitals in The Netherlands. Adverse drug events were collected by spontaneous reporting (doctor and nurse reports) and by daily ward visits, during which the patients were interviewed by a hospital pharmacist (patient reports). Criteria for relative value of the reported adverse drug events were the number of potentially serious reactions, the number of reactions not mentioned in the patient information leaflet and the number of reactions reported to new drugs (5 years or less on the Dutch market). No formal causality assessment was applied.

RESULTS

Over a period of 2 months in 1996 (Hospital I) and 2 months in 1997 (Hospital II) a total of 620 patients were included in the study and adverse drug events were reported in 179 (29%) of these cases. Doctors reported a statistically significant larger number of serious (26% of all doctor reports; odds ratio (OR) 3.2; confidence interval (CI) 1.2-8.7) and unknown (39%; OR 2.5; CI 1.0-6.0) adverse drug events than patients themselves during the daily ward visit. Doctors also reported more serious and unknown adverse drug events than nurses. Adverse reactions to new drugs were reported during the daily ward visit only (8% of all daily ward visit reports).

CONCLUSION

This study reconfirms that doctors are the main source for reports of serious and unknown adverse drug events in hospitalized patients. However, patients themselves seem to report more adverse reactions to new drugs (during the daily ward visit). By focusing on patients using new drugs, the daily ward visit might become cost-effective. This needs to be explored in future studies.

Determinants of psychotropic drug usage in a general intensive care unit

During a 3-month period, determinants of psychotropic drug utilization (sex, age, length of stay, reason for admission, disease severity) and data on psychotropic consumption (type of medication--antidepressants, benzodiazepines and antipsychotics--dosage and length of treatment) were retrospectively collected in a general intensive care unit of a Dutch university hospital. Daily exposure to psychotropics was standardized in number of Defined Daily Doses (DDD). Benzodiazepines were used by 35.8% of all patients (137) during their stay in the ICU whereas 17.5% of all patients used a neuroleptic agent. Antidepressants were hardly prescribed. High doses of benzodiazepines (9.9 DDDs) and low doses of antipsychotics (0.5 DDDs) were prescribed, which probably reflect the unusual nature of this critically ill group of patients compared with the reference group for DDD's. Clear patterns of determinants of psychotropic drug use in ICU patients were found and both benzodiazepines, antipsychotics and combined use of these agents could be associated with the determinants assessed. The time patterns we found in terms of length of stay give clues for further investigations in order to rationalize psychotropic drug use in the management of severely ill and complex patients.

NSAIDs associated with increased risk of congestive heart failure in elderly patients taking diuretics

BACKGROUND

Both diuretics and nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used, in particular among the elderly. The use of NSAIDs may decrease the efficacy of diuretics and induce congestive heart failure (CHF) in patients treated with diuretics.

OBJECTIVE

To investigate the risk of CHF associated with combined use of diuretics and NSAIDs in patients older than 55 years.

METHODS

We conducted a study in a base cohort of 10,519 recipients of diuretics and NSAIDs identified in the PHARMO database during the period from 1986 through 1992. The incidence density of hospitalizations for CHF during exposure to both diuretics and NSAIDs (index) was compared with that during exposure to diuretics only (reference).

RESULTS

We found an overall increased risk of hospitalization for CHF during periods of concomitant use of diuretics and NSAIDs compared with use of diuretics only (crude relative risk, 2.2; 95% confidence interval, 1.7-2.9). After adjusting for cofactors including age, sex, history of hospitalization, and drug use, a 2-fold increased risk remained (relative risk, 1.8; 95% confidence interval, 1.4-2.4).

CONCLUSION

Use of NSAIDs in elderly patients taking diuretics is associated with a 2-fold increased risk of hospitalization for CHF, especially in those with existing serious CHF.

Usage patterns of benzodiazepines in a Dutch community: a 10-year follow-up

Only a few longitudinal studies have addressed benzodiazepine use over time. We therefore conducted a 10-year follow-up study (1983-1992) on usage patterns of benzodiazepines in a Dutch community of 13 500 people. Use decreased during the time of the study. Twelve (1983) to ten (1992) percent of the inhabitants was a recipient at least once a year of a benzodiazepine prescription. The use by gender showed more women using more prescriptions as men. Women were not prescribed more DDDs per prescription as men. Individual benzodiazepines showed differences in use by gender. Use increased with age among both women and men. Most of the users were 55 years or older. One out of three patients was either an incidental user (1-30 days use in one calendar year), a regular (31-180 days), or a long term user (more than 180 days). The use of long half-life hypnotics decreased, the use of the short half-life ones showed an increase. Behind a stable overall trend we found strong fluctuations in use of individual benzodiazepines.

Non-puerperal lactation associated with antidepressant drug use

AIMS

The aim of the present study was to estimate the relative risk of non-puerperal lactation in patients using antidepressants in general, and specifically for serotonergic (selective serotonin reuptake inhibitors (SSRIs) and clomipramine) and non-serotonergic antidepressants.

METHODS

All suspected adverse drug reactions in women and reported from January 1986 until August 1996 to the Netherlands Pharmacovigilance Foundation, a spontaneous adverse drug reaction reporting programme, were analysed. Adverse drug reaction (ADR) reporting odds ratios, defined as the ratio of the exposure odds among reported cases of non-puerperal lactation to the exposure odds of reported other ADRs, were calculated adjusted for age and year of reporting.

RESULTS

Thirty-eight cases of non-puerperal lactation were reported, of which 15 were associated with the use of antidepressant drugs. In general, antidepressants were associated with a higher risk of non-puerperal lactation in comparison with other drugs (ADR reporting odds ratio 8.3 [95%CI: 4.3-16.1]). Serotonergic antidepressants (selective serotonin reuptake inhibitors (SSRIs) and clomipramine) were associated with a higher risk (OR 12.7 [95%CI: 6.4-25.4]), whereas other antidepressants were not (OR 1.6 [95%CI: 0.2-11.6]), compared with all other drugs.

CONCLUSIONS

Our results indicate that serotonergic antidepressants are associated with an approximately eight times higher risk of non-puerperal lactation compared with other antidepressants. This effect is probably mediated by an indirect inhibition effect of serotonin on the dopaminergic transmission. This finding is in line with the occurrence of other antidopaminergic effects, such as extrapyramidal symptoms, in patients using serotonergic antidepressants.

Incidence of antidepressant drug use in older adults and association with chronic diseases: the Rotterdam Study

A follow-up study was conducted among men and women aged 55 years and over living in the community in order to estimate the incidence of initiation of antidepressant drug use and the association with chronic diseases. The study population consisted of 7,812 individuals. Overall, the incidence density for starting therapy with an antidepressant drug was 13.5 per 1000 person-years. The cumulative incidences after 1, 2 and 3 years were 1.3, 2.7 and 4.0%, respectively. The incidence in women was almost twice that in men and slightly higher in participants older than 70 years than in those younger than 70 years. The majority of the antidepressants prescribed were tricyclic antidepressants (65%), followed by selective serotonin reuptake inhibitors (23%) and other (12%) antidepressants. Only a minority (23%) received a dose considered effective for the indication of depression. Selective serotonin reuptake inhibitors were more often prescribed in an adequate dosage (68%) than were tricyclic antidepressants (12%) and other antidepressants (8%). Of the chronic diseases studied, only osteoarthritis and a history of stroke were predictors of initiation of antidepressant drug use after adjustment for age, sex and medical consumption. Hypertension, history of myocardial infarction, diabetes mellitus, rheumatoid arthritis, glaucoma, cognitive impairment and Parkinson's disease were not associated with future antidepressant drug use. No relevant differences were observed with respect to the choice of type of antidepressant drug among patients with chronic diseases. The present study indicates that each year antidepressant drug therapy is initiated in approximately 1.3% of the elderly. In general, the presence of chronic somatic diseases was not predictive of initiation of antidepressant drugs. Tricyclic antidepressants in this age group and in patients with certain chronic diseases may not be the optimal choice given their side-effects profile and drug-drug and drug-disease interactions. The predominance of these agents in the present study calls for further attention.

Channeling of three newly introduced antidepressants to patients not responding satisfactorily to previous treatment

The demand for knowledge about differences in effectiveness, tolerability, safety, and economic outcomes between and within groups of antidepressant drugs when used in routine daily clinical practice is growing. For gaining this knowledge, observational pharmacoepidemiologic studies are often the most feasible option. However, the results of such studies can only be valid if either patient baseline characteristics associated with the outcome under study are similar or if differences can be adjusted for in the analysis. The aim of this study was to evaluate to what extent and for what type of patients three antidepressant drugs recently introduced in The Netherlands (mirtazapine, sertraline, and venlafaxine) were prescribed during the first year after their introduction and whether there were differences compared with longer-available antidepressant drugs. For this purpose, prescription drugs histories from 20 pharmacies serving a population of approximately 200,000 persons were analyzed. One year after their introduction, the newly introduced antidepressant t drugs accounted for approximately 6% of new uses of all antidepressant drugs. In comparison to longer-available antidepressant, the newly introduced antidepressant drugs were more often prescribed for patients with prior prescriptions of another antidepressant drug (rate ratio [RR] 2.7 [95% confidence interval [CI], 2.3-3.0]), for patients with prior prescriptions of other psychotropic medicines (RR 1.3 [95% CI, 1.1-1.4), and by psychiatrists (RR 1.9 [95% CI, 1.6-2.2]). In addition, the newly introduced antidepressant drugs seemed to be more often, although not significantly, prescribed for patients who had been hospitalized on a psychiatric ward (RR 1.5 [95% CI, 0.9-2.5]). No differences were observed with regard to age and gender distribution, the total number of medicines prescribed, and prescriptions of any cardiovascular or gastrointestinal medicine. These finding suggest that a significant proportion of the patients receiving one of the newly introduced antidepressant drugs did not respond satisfactorily to previous pharmacologic treatment. This channeling phenomenon may have important consequences for the interpretation of observational comparisons between different antidepressant drugs after their introduction.

Assessing asthma management from interviews of patients and family physicians

Directed self-care is recommended in asthma. Adequate patient education and follow-up are nevertheless necessary to optimize outcomes. We compared the agreement between detailed information on asthma history and management, collected from the patient and the family physician, to validate the files of physicians and to assess patients' knowledge, attitude, and behavior concerning asthma. A sample of 54 asthma patients were interviewed in detail about use of medications and self-care practice; 36 family physicians (FPs) were interviewed concerning asthma therapy, history, and attitudes of the same patients. Forty-eight percent of the patients expressed negative attitudes toward inhaled corticosteroids, for reasons of safety or lack of efficacy. Less than 20% of the patients made regular use of a peak flow meter. Eighty-three percent of the patients usually obtained prescriptions for asthma therapy from their FP, but on average, only 40% of these prescriptions were provided during visits specific to asthma. FPs were not optimally informed of actual treatments and outcomes and had poor perception of patients' attitudes toward treatment. Nonetheless, in about 30% of the patients, FPs identified risk factors for adverse outcome, such as depression and family conflicts. A majority of interviewed patients had a negative perception of anti-inflammatory therapy, specifically relating to issues of safety and efficacy. Peak flow meters were seldom used and therapy was commonly prescribed outside visits specific to asthma. Despite being centrally involved in the care of asthma patients, FP did not optimally assess therapy and outcomes. The findings suggest suboptimal education and health status in this asthma population.

Actual use of inhaled corticosteroids and risk of hospitalisation: a case-control study

BACKGROUND

The relationship between therapy and adverse outcome in asthma is debated especially for naturally occurring situations. This is due in part to insufficient information regarding actual use of medications.

OBJECTIVE

This study was conducted to clarify the relationship between actual intake of anti-asthma drugs and asthma hospitalisation, considered as an outcome.

METHODS

A case-control study was performed. Patients hospitalised for an asthma exacerbation were matched to community controls identified in surrounding general practices. Patients were questioned to identify prior use of anti-asthma medications, level of use of inhaled corticosteroids and attitude towards therapy.

RESULTS

Twenty-three cases and 31 matched controls were interviewed. Cases tended to have more severe asthma than controls, as judged by more frequent use of oral corticosteroids. Cases tended to make more frequent use of oral xanthines and inhaled anticholinergics, but the proportion of patients using inhaled beta 2-adrenoceptor agonists and inhaled corticosteroids was similar in both groups. Use of lower doses of inhaled corticosteroids was associated with an increased risk of hospitalisation, while higher dosage was associated with decreased risk. Cases and controls differed as to their answers to a questionnaire concerning attitudes: cases expressed less interest in optimal usage of inhaled corticosteroids than controls; they also expressed more confidence in inhaled beta 2-agonists. When both risks were combined, overconfidence in beta 2-agonists and suboptimal use of inhaled steroids, the relationship with hospitalisation was significant (OR 5.5, 95% CI 1.1; 26.1).

CONCLUSION

The results suggest that patients' attitudes to inhaled corticosteroids and actual consumption of these medications are directly related to adverse outcome in asthma.

Antiallergic and antitussive medications: extent of use and relationship to asthma exacerbations

BACKGROUND

Asthma patients are frequently exposed to antiallergic and antitussive medications, in addition to their respiratory treatment. These medications interfere with inflammatory pathways common to all atopic diseases and could affect asthma.

OBJECTIVES

To investigate associations between antiallergic and antitussive medications and the occurrence of asthma exacerbations and to assess the extent of use of these medications in asthma.

METHODS

Regular users of anti-asthma medications were identified in a drug dispensing database. A base-cohort of asthma patients was identified using age and exposure criteria. A nested case-control study was performed within the base-cohort: the outcome was defined as a new dispensing of oral corticosteroids and matched cases and controls were compared regarding exposure to antiallergic medications. Odds ratios (OR) were computed by conditional logistic regression and adjustment incorporated markers for asthma severity.

RESULTS

680 asthma patients were followed in the base-cohort for an average duration of 1390 days. Antitussives, antihistamines and nasal corticosteroids were used by respectively 40, 30 and 13 per cent of the asthma population. Among the patients, 134 cases were pair matched with controls. In these pairs, antitussives showed a significant association with asthma exacerbations, with an OR of 3.1. The association had borderline significance for antihistamines and was not significant for nasal corticosteroids. The results were not modified by adjustment for disease severity.

CONCLUSIONS

This study confirms that antitussives and antihistamines are commonly used by asthmatics and indicates that both classes are associated with increased occurrence of asthma exacerbations; assessing causality from present data is, however, difficult. Nasal corticosteroids are used less often and are not associated with the outcome. Antihistamine and antitussive medications should be more thoroughly investigated in asthma patients.

Asthma medications and disease exacerbations: an epidemiological study as a method for asthma surveillance

Recent experimental and epidemiological studies have suggested that outcomes of asthma are significantly influenced by treatment patterns. This study was conducted in order to investigate the links between treatment patterns in asthmatics and occurrence of disease exacerbations. We performed a nested case-control study in a cohort of 680 asthmatics identified between 1986 and 1991 in a drug dispensing database. After validation in a pilot study, the intermittent use of oral corticosteroids was used as a proxy for asthma exacerbations. Cases with an exacerbation (n=133) were pair-wise matched with controls. The type of medications used for the usual treatment of asthma were examined in relation to the risk of asthma exacerbation. The use of oral xanthines and inhaled fenoterol but not of inhaled salbutamol, corticosteroids, cromoglycate and ipratropium bromide was associated with an increased probability of asthma exacerbation. Within the cohort, the proportion of subjects dispensed inhaled corticosteroids rose from 12 to 27% between 1986 and 1991. The proportion of subjects using inhaled bronchodilators without inhaled corticosteroids also decreased over this period of time. The identification of markers of asthma exacerbations made it possible to link the probability of adverse outcome risk for such exacerbations with treatment patterns. This method could be useful in further development of asthma surveillance using drug dispensing databases.

Hypoglycaemia associated with use of inhibitors of angiotensin converting enzyme

The use of angiotensin-converting-enzyme (ACE) inhibitors has been associated with increased insulin sensitivity in diabetic patients. Although such an effect could be beneficial in the treatment of hypertension or congestive heart failure in diabetic patients, it might also precipitate severe hypoglycaemia. To test this hypothesis we carried out a nested case-control study, using data in the Dutch PHARMO system (1986-92), among diabetic patients treated with insulin or with oral antidiabetic drugs, who were admitted to hospital with hypoglycaemia. We identified 94 patients who had been admitted with hypoglycaemia and selected 654 controls from the same cohort. With adjustment for a wide range of potential confounding factors, hypoglycaemia was significantly associated with current use of ACE inhibitors (odds ratio 2.8 [95% CI 1.4-5.7]). Both among users of insulin and among users of oral antidiabetic drugs, use of ACE inhibitors was significantly associated with an increased risk of hospital admission for hypoglycaemia (2.8 [1.2-6.4] and 4.1 [1.4-12.2], respectively). Although ACE inhibitors have several advantages over other antihypertensive drugs in diabetes, the risk of hypoglycaemia should be taken into account. Further investigation of the mechanism is needed since as many as 13.8% of all hospital admissions for hypoglycaemia might be attributable to use of ACE inhibitors.

Information on drug use in the elderly: a comparison of pharmacy, general-practitioner and patient data

Management of pharmacotherapy by the pharmacist and the general practitioner can be a difficult task in elderly patients in whom there is a high concomitant, long-term drug use. Adequate information on drug use is essential in managing pharmacotherapy as well as in an accurate assessment of drug exposure in pharmacoepidemiologic studies. In this study data from computerized pharmacy records, general-practitioner registries and home interviews with 100 elderly patients were compared. Pharmacy records contained 80% of all the prescriptions found at the home interviews, while in general-practitioner data 40% could be traced. Use of drugs dispensed long ago reduced the validity of pharmacy and general-practitioner data. Data on analgesics (70% was found) and respiratory drugs (68%) were less traceable compared to cardiovascular (83%) and psychotropic drugs (81%). Automated pharmacy records are an important source of longitudinal data on drug use and will improve the assessment of drug exposure in pharmacoepidemiologic studies and optimize pharmaceutical care.

Public health problems and the rapid estimation of the size of the population at risk. Torsades de pointes and the use of terfenadine and astemizole in The Netherlands

Recently, the use of astemizole and terfenadine, both non-sedating H1-antihistamines, caused considerable concern. Several case reports suggested an association of both drugs with an increased risk of torsades de pointes, a special form of ventricular tachycardia. The increased risk of both H1-antihistamines was associated with exposure to supratherapeutic doses; for terfenadine the risk was also associated with concomitant exposure to the cytochrome P-450 inhibitors ketoconazole, erythromycin and cimetidine. To predict the size of the population that runs the risk of developing this potentially fatal adverse reaction in the Netherlands, the prevalence of prescribing supratherapeutic doses and the concomitant exposure to terfenadine and cytochrome P-450 inhibitors was studied. Data were obtained from the PHARMO data base in 1990, a pharmacy-based record linkage system encompassing a catchment population of 300,000 individuals. The results of the study showed that the prescribing of supratherapeutic doses and the concomitant exposure to terfenadine and cytochrome P-450 inhibitors was low. Furthermore, the results of a sensitivity analysis showed that the risk of fatal torsades de pointes has to be as high as 1 in 10,000 to cause one death in the Netherlands in one year.

Channelling of controlled release formulation of ketoprofen (Oscorel) in patients with history of gastrointestinal problems

STUDY OBJECTIVE

The aim was to determine if a new controlled release formulation (Oscorel) of the non-steroidal anti-inflammatory drug (NSAID) ketoprofen has been preferentially prescribed in patients with prior history of gastro-intestinal disturbances.

DESIGN

The study was a pharmacy records based comparison of the rates of prior prescribing of drugs indicated for peptic ulcer treatment in first recipients of Oscorel in 1989 versus recipients of other NSAID products.

SETTING

A representative panel of Dutch community pharmacies serving approximately 425,000 people was used.

MAIN RESULTS

Oscorel was launched in January 1989. Data on prescriptions dispensed in 1987-1988 to a total of 837 first users of Oscorel were analysed and compared with the dispensing history of a reference population including 30,787 patients who did not receive a prescription for Oscorel during 1989. Compared to the reference population, first users of Oscorel included a greater proportion of females, of patients 75 years and older, of heavy users of NSAIDs, and of patients switching among different NSAIDs. A total of 24.1% of first users of Oscorel had received peptic ulcer therapy in 1987-1988, versus 15.7% of the reference population. The rate ratio was 1.54, with 95% confidence interval of 1.36-1.74. Adjustment for stratifying variables caused only minor changes in the rate ratio, which remained stable on 1.5.

CONCLUSIONS

Oscorel appears to have been channelled into use in patients with recognised risk factors for gastrointestinal toxicity. This preferential prescribing probably resulted from expectations and claims that this product has a lower risk of such toxicity.

Utilization patterns of non-steroidal anti-inflammatory drugs in an open Dutch population

Non-steroidal anti-inflammatory drugs represent an important drug class in ambulatory care. A utilization study among half a million persons showed that 8.6% could be identified as having used one or more non-steroidal anti-inflammatory drugs (excluding salicylates) in 1987. Data were drawn from a representative sample of pharmacy records which comprise full medication histories of individual patients. Overall utilization of non-steroidal anti-inflammatory drugs was 10.8 defined daily doses/(1000 persons.day). Approximately three quarters of the patients are 'incidental' users and receive non-steroidal anti-inflammatory drugs for a relatively short time (30 days or less). Patients who were identified as 'regular' (31-210 days of therapy) and 'heavy' (greater than 210 days of therapy) users, accounted for 21.2% respectively 4.8% of all users. 'Heavy' users are responsible for 17.3% of all non-steroidal anti-inflammatory drug prescriptions. Especially the elderly and females are prone to be 'heavy' users. Five drugs account for 90.4% of all prescriptions (diclofenac, ibuprofen, naproxen, piroxicam, indomethacin). A total of 71.1% of the patients with more than one prescription for non-steroidal anti-inflammatory drugs switched in therapy. There are two classes of concomitant drug use especially relevant with respect to detecting non-steroidal anti-inflammatory drugs-associated risks: H2 blockers and antacids (belonging to anatomical therapeutic and chemical anatomic class A) and diuretics (belonging to anatomical therapeutical chemical anatomic class C). More than half of the 'heavy' users showed concomitant use of drugs in these classes.