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Biomedical subjects

R M Herings

Publications and source records attributed to R M Herings.

At least 19 recordsLinked to original sources
PubMed2001

Tendon disorders attributed to fluoroquinolones: a study on 42 spontaneous reports in the period 1988 to 1998.

OBJECTIVE: Fluoroquinolone antibiotics have been associated with tendinitis and tendon rupture. In this paper we report on the followup of 42 spontaneous reports of fluoroquinolone-associated tendon disorders. METHODS: This study is based on cases of fluoroquinolone-associated tendon disorders reported to the Netherlands Pharmacovigilance Foundation Lareb and the Drug Safety Unit of the Inspectorate for Health Care between January 1, 1988, and January 1, 1998. By means of a mailed questionnaire, we collected information on the site of injury, onset of symptoms, treatment, and course of the tendon disorder as well as information on possible risk factors and concomitant medication. RESULTS: Of 50 mailed questionnaires, 42 (84%) were returned. The data concerned 32 patients (76%) with tendinitis and 10 patients (24%) with a tendon rupture. Sixteen cases (38%) were attributed to ofloxacin, 13 (31%) to ciprofloxacin, 8 (19%) to norfloxacin, and 5 (12%) to pefloxacin. There was a male predominance, and the median age of the patients was 68 years. Most of the reports concerned the Achilles tendon, and 24 patients (57%) had bilateral tendinitis. The latency period between the start of treatment and the appearance of the first symptoms ranged from 1 to 510 days with a median of 6 days. Most patients recovered within 2 months after cessation of therapy, but 26% had not yet recovered at followup. CONCLUSION: These reports suggest that fluoroquinolone-associated tendon disorders are more common in patients over 60 years of age. Ofloxacin was implicated most frequently relative to the number of filled prescriptions in the Netherlands.

Adult↗
PubMed2001

Antipsychotic-induced extrapyramidal syndromes. Risperidone compared with low- and high-potency conventional antipsychotic drugs.

AIM: To compare the risk of extrapyramidal syndromes (EPS) between patients using risperidone and those using low-potency conventional antipsychotic drugs (APDs) in outpatient clinical practice, as measured by the use of anticholinergic medication. We tried to replicate results from previous clinical trials that compared risperidone with high-potency APDs. METHOD: Data was obtained from the PHARMO database containing filled prescriptions of 450,000 community-dwelling people in The Netherlands from 1986 to 1998. From the patients aged 15-54 years who had been newly treated with APDs, we defined mutually exclusive cohorts according to the APD first prescribed to a patient. APD exposure was followed until the first prescription of anticholinergic medication and was censored when APD prescribing was interrupted or switched. We estimated relative risks between risperidone and commonly used low-potency and high-potency APDs using Cox proportional hazards models, adjusting for age, gender, dose and other potential confounders. RESULTS: In 4094 patients who had been newly prescribed antipsychotic drugs, the overall incidence rate of anticholinergic drug therapy was 556 per 1000 person-years, which was dose dependent. Prescribed doses of all antipsychotics were low. While, in accordance with previous trials, risperidone showed a lower risk of EPS than the high potency APDs such as haloperidol (RR 0.26; 95% CI 0.10-0.64), we did not observe a lower EPS rate than low-potency APDs (risperidone vs thioridazine RR 1.73, 95% CI 0.49-6.13; risperidone vs pipamperone RR 2.50, 95% CI 0.78-8.04). CONCLUSION: The reduced EPS rates observed when comparing risperidone with high-potency antipsychotics such as haloperidol may not apply to comparisons with low-potency drugs.

Adolescent↗
PubMed2001

Evaluating adverse cardiovascular effects of drug treatment for benign prostatic hyperplasia (BPH): methodological considerations.

When studying the effects of drug exposure in diseases with a long asymptomatic clinical course, exposure classification may be biased by the gradually developing "visibility" of the disease. Benign prostatic hyperplasia (BPH) is such a disease. We found that cardiovascular morbidity is two times more prevalent in patients starting drug treatment for BPH when compared to age-matched population controls. This resulted in a difference of cardiovascular prognostic factors between the exposed and non-exposed. This feature can jeopardize the validity of non-randomized comparisons of drug effects. Moreover, the existence of non-treatment strategies, disease under-reporting, and an elderly population with a high baseline risk of experiencing (cardiovascular) outcome events were encountered as methodological problems. When studying adverse cardiovascular effects in patients using BPH products in a non-randomized fashion, an important question is whether we can measure in the database all relevant prognostic factors and use the information for statistical adjustment. This question is an important challenge to observational research and once again stresses the need for control of possible biases in choosing an appropriate study design.

5-alpha Reductase Inhibitors↗
PubMed2001

Fluoroquinolone use and the change in incidence of tendon ruptures in the Netherlands.

INTRODUCTION: Shortly after their introduction, fluoroquinolones were associated with reports of tendinitis and tendon rupture. During the past years, the number of reports has risen, possibly because of an increased use of fluoroquinolones. In this study, we describe the use of fluoroquinolones in the Dutch community and the possible public health effects of an association between fluoroquinolone use and tendon ruptures. METHODS: In the PHARMO drug database we identified all prescriptions for fluoroquinolones in the period 1991-1996. The incidence of fluoroquinolone use was expressed as the number of fluoroquinolone episodes per 1000 inhabitants in one year, and extrapolated to the Dutch population after standardisation on age and gender. The annual incidence of non-traumatic tendon ruptures in the period 1991-1996 was calculated with data from the nation-wide hospital registry. The expected number of fluoroquinolone attributable tendon ruptures was calculated on the basis of the use of fluoroquinolones, the number of non-traumatic tendon ruptures and an assumed relative risk of 1.5-10. RESULTS: In 1996, approximately 251,000 patients experienced 318,000 episodes of fluoroquinolone use in the Netherlands. Females used more often fluoroquinolones than males, and the number of episodes increased exponentially with age. In the period 1991 through 1996, the absolute number of fluoroquinolone episodes increased by 160%, from 122,000 to 318,000. The absolute number of hospitalised tendon ruptures increased with 28%, from 768 in 1991 to 984 in 1996. Assuming a relative risk of 1.5 to 10.0, 1 to 15 tendon ruptures could be attributed to fluoroquinolone use in 1996. Only 7% of the observed increase could be attributed to the increased use of fluoroquinolones. If the total increase of hospitalised non-traumatic tendon ruptures would be attributable to the increase in fluoroquinolone use, this would mean that the risk of non traumatic tendon ruptures to fluoroquinolones would be more than 250 times the risk during non-use. CONCLUSION: In the Netherlands, a large simultaneous increase in non-traumatic tendon ruptures and fluoroquinolone use was observed in the period between 1991 to 1996. Assuming a relative risk of 1.5 to 10.0 for tendon ruptures during fluoroquinolone use, only 0.5 to 7% of the increase in non-traumatic tendon ruptures could be attributed to the increased fluoroquinolone use. The increase in the incidence of non-traumatic hospitalised tendon ruptures in the Netherlands is not likely to be explained solely by the increased use of fluoroquinolones.

Adult↗
PubMed2001

Determinants of pharmacists' interventions linked to prescription processing.

AIM OF STUDY: The role of pharmacists in today's healthcare is changing rapidly. As they are close to the prescribing process, pharmacists are in the position to identify and adjust prescribing errors before dispensing. The objective of this study was to identify relevant determinants of interventions directly linked to prescription processing in community pharmacy. METHODS: As part of a yearly continuing education programme, all community pharmacies in the region of 'Zealand' (N = 23) in the south-west of The Netherlands kept detailed records of all interventions directly linked to prescription processing during one week in May 1998. For every patient involved in an intervention, a control-patient was matched on pharmacy practice, date, gender and age. RESULTS: A total of 39,357 prescriptions were evaluated by the 23 pharmacies during the one-week intervention programme. Out of these, one out of 10 resulted into an intervention. Being a first prescription in a new treatment episode was found to be a significant determinant (OR 1.75, 95 CI% 1.18-2.33). Variables reflecting drug therapy complexity (> 3 prescribers, > 15 prescriptions in 3 months before, > 3 different medications) showed all ORs higher than 1.00, but not significant. When looking at the individual drug categories, anti-infectives, respiratory drugs and cardiovascular medicines came out as important drug classes for intervention risk. We could not find any association between the number of signals per pharmacy and the number of interventions. CONCLUSION: The 'whistle-blower' model of pharmacy based interventions is a valid one but needs a targeted and integral way of implemented thinking and use of information technology. In such an environment, interventions are a logical step of in-process quality control in the drug usage system.

Aged↗
PubMed2001

Long-term therapy with spironolactone.

OBJECTIVE: To evaluate the duration of therapy with spironolactone in daily practice. METHOD: A retrospective follow-up of a cohort of patients with a first prescription for spironolactone between January 1, 1990 and December 31, 1996 and at least one hospital discharge for CHF in the preceding year. RESULTS: 243 patients met the inclusion criteria and were followed until the end of data collection. The average starting dosage of spironolactone was 55 mg. 143 patients (58.8%) discontinued spironolactone therapy before the end of follow-up. 98 patients (40.8%) discontinued within 6 months of follow-up. Of the 137 patients (56.4%) who did use spironolactone and an ACE-inhibitor concomitantly, only 45 (32.8%) continued this combination until the end of follow-up. The remainder of the patients discontinued either the ACE-inhibitor (10.9%) or spironolactone (12.4%) or both (43.8%). CONCLUSION: While the reasons for discontinuation remain unclear, our data suggest that it is difficult to keep patients on both drugs. It is not certain whether these findings from past spironolactone use can be extrapolated to future use. Patients in the general population received higher average spironolactone dosages compared to the RALES study (55 mg vs. 26 mg), possibly resulting in more adverse effects and partly explaining the high discontinuation rate.

Adult↗
PubMed2001

Risk of extrapyramidal syndromes with haloperidol, risperidone, or olanzapine.

OBJECTIVE: To compare the risk of extrapyramidal syndrome (EPS) between risperidone, olanzapine, and haloperidol, taking into account patients' past antipsychotic drug use and past EPS. METHODS: Data were obtained from the PHARMO-database, containing filled prescriptions of 450,000 community-dwelling people in the Netherlands from 1986 through 1999. We defined cohorts of first-time users of haloperidol, risperidone, or olanzapine aged 15 to 54 years. In the first 90 days of treatment, we assessed the occurrence of EPS, defined as first use of any antiparkinsonian agent. We estimated relative risks of EPS for risperidone and olanzapine versus haloperidol using a Cox proportional hazards model. Patients were subdivided according to prior use of antipsychotic and antiparkinsonian drugs. RESULTS: We identified 424 patients starting treatment with haloperidol, 243 with risperidone, and 181 with olanzapine. Prior use of antipsychotic plus antiparkinsonian medication was significantly more frequent among users of risperidone and olanzapine than in those using haloperidol (36.2%, 40.3%, and 4.5%, respectively; p < 0.001). Within most subgroups of comparable treatment history, patients using risperidone and olanzapine showed reduced risks of EPS compared with haloperidol, although some of these findings did not reach statistical significance (RR 0.03-0.22). However, this was not observed for patients using risperidone who had experienced EPS in the past (RR 1.30; 95% CI 0.24 to 7.18). CONCLUSIONS: In general, we observed reduced risks of EPS for risperidone and olanzapine compared with haloperidol within subgroups of patients with a similar treatment history. However, the added value of risperidone in patients who have experienced EPS in the past needs further study.

Adolescent↗
PubMed2001

An epidemiological approach to assess the economic burden of NSAID-induced gastrointestinal events in The Netherlands.

OBJECTIVE: To use the population attributable risk (PAR) to estimate the treatment costs resulting from nonsteroidal anti-inflammatory drug (NSAID)-induced gastrointestinal (GI) morbidity. DESIGN: Two case-control studies with the following outcomes: (i) the start of therapy with gastroprotective agents (GPAs) and (ii) hospitalisations for GI events. SETTING: Community-dwelling inhabitants of defined areas in The Netherlands covering the period 1989 to 1998. All analyses were performed from the perspective of a third-party payer. METHODS: Risk and exposure data were obtained from the Dutch PHARMO system, a population-based register of drug-dispensing records and hospital records. The PAR was estimated based on stratum-specific prevalence estimates of NSAID use and the corresponding odds ratios (ORs) obtained from the case-control studies. Cost data were obtained from Dutch national hospital discharge records and tariffs. Annual treatment costs of NSAID-induced GI events were calculated based on the PAR in the sample population and extrapolated to the total population using national demographic data. RESULTS: The adjusted ORs for starting GPA use and hospitalisation for GI events were 6.6 [95% confidence interval (CI): 5.5 to 7.8] and 5.0 (95% CI: 4.0 to 6.2), respectively, in NSAID users compared with controls. Variation of OR with age among NSAID users suggested that prevention of GI events is most efficient among the elderly. The total annual cost (1998 values) of GPA use and hospitalisations for GI events attributable to the use of NSAIDs was 59 million euro (EUR) [95% CI: EUR38.5 million to EUR98 million]. More than 65% of these NSAID-induced costs, EUR38 million, can be attributed to long term users of NSAIDs, representing only 9.3% of all users of NSAIDs. CONCLUSIONS: The PAR can be used to estimate the costs of drug-induced morbidity and changes in costs resulting from substitutions with other drugs. For each EUR1.00 spent on NSAIDs, an additional EUR0.68 (excluding costs for prophylactic treatment) can be added for the treatment of GI adverse events.

Adolescent↗
PubMed2000

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.

Aged↗
PubMed2000

Influence of question structure on the recall of self-reported drug use.

Epidemiological studies often rely on self-reported information as a source of drug exposure. Several studies have evaluated the accuracy of self-reported information on drug use. The influence of question structure on the accuracy of recall, however, has not been studied extensively in these studies. In this study we examined the recall accuracy of questionnaire information on drug use in a ongoing public health survey with special attention to the influence of question structure on sensitivity of recall. A sample of 372 hypertensive subjects for whom questionnaire information and pharmacy records were available was examined. Self-reported information on drug use was obtained through questions about medications used for a specific condition and one final open-ended question. This information was compared with the pharmacy medication history. About 71% of all drugs that were currently in use according to the pharmacy records were recalled through the self-administered questionnaire, and 94% of all drugs mentioned in the questionnaire could be traced in the pharmacy records. Recall sensitivity was higher for questions about medications used for a specific indication (88%) than for the open-ended question (41%). The type of drug that was used might have caused part of this difference in recall. We conclude that questionnaire structure might be of influence on the accuracy of recall of self-reported drug use, and more attention should be paid to the structure of questions on drug use.

Adult↗
PubMed2000

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.

Aged↗
PubMed2000

Use of prevalence and incidence measures to describe age-related prescribing of antidepressants with and without anticholinergic effects.

To evaluate whether physicians avoid prescribing highly anticholinergic antidepressants (AAD) in the elderly, a population-based retrospectively data analysis was performed using databases from a Dutch health insurance company. Data collected on approximately 240,000 persons covered the period from 1 July 1993 to 1 January 1996. The prevalence and the incidence (number of new starters) of antidepressant use was measured over 1994 and 1995. Use of AAD was proportionally higher in the elderly in terms of both prevalence and incidence rates; the ratio of starters of AAD versus starters of non-AAD in 1994 increased steadily with age (from 0.54 in the age group 20-29 to 1.15 in the age group 60-69). In 1995 these incidence ratios decreased (0.41 to 0.99, respectively); however, the decrease was higher in the younger age groups. The data indicate that in the population studied, physicians do not refrain from prescribing highly anticholinergic agents to older patients despite their potential adverse drug reactions in this age group. This study also indicates that prevalence and incidence rates can be extracted from reimbursement data and give insight into actual prescribing practices.

Adult↗
PubMed1999

A population-based case-cohort study of drug-associated agranulocytosis.

BACKGROUND: Agranulocytosis is a life-threatening disorder, often caused by drugs. Incidences or risks of drug-induced agranulocytosis are not well known, since it is rare. METHODS: To determine the risk of drug-associated agranulocytosis as a reason for admission to Dutch hospitals, we performed a population-based case-cohort study. Hospital discharge data came from the Dutch Centre for Health Care Information, Utrecht, which contains data on all general and university hospitals in the Netherlands. The reference cohort consisted of all persons in the catchment area of the Pharmaco Morbidity Record Linkage System (PHARMO RLS) in the Netherlands, composing a population of approximately 220 000 to 484 000 persons from 1987 through 1990. All admissions during that period with agranulocytosis or related diagnoses were included in the study (n = 923). The potential causes of agranulocytosis were assessed in all cases classified as probable or possible agranulocytosis. RESULTS: Discharge summaries were received of 753 admissions, of which 678 contained enough information for analysis. Of the 678,108 were classified as "agranulocytosis probable" or as "agranulocytosis possible." In 75 of these 108 cases, agranulocytosis had been the reason for admission. Fifteen patients had used methimazole within 10 days before developing agranulocytosis; 2, carbimazole; 9, sulfasalazine; 8, sulfamethoxazole-trimethoprim; 4, clomipramine hydrochloride; and 2, dipyrone with analgesics, yielding adjusted relative risks of agranulocytosis of 114.8 (for thyroid inhibitors combined) (95% confidence interval [CI], 60.5-218.6), 74.6 (95% CI, 36.3-167.8), 25.1 (95% CI, 11.2-55.0),20.0 (95% CI, 6.1-57.6), and 26.4 (95% CI, 4.4-11.1), respectively. CONCLUSIONS: The highest relative risks were found for thyroid inhibitors, sulfamethoxazole-trimethoprim, sulfasalazine, clomipramine, and dipyrone combined with analgesics.

Adult↗
PubMed1999

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.

Adolescent↗
PubMed1999

Agreement between self-reported antihypertensive drug use and pharmacy records in a population-based study in The Netherlands.

From 1987 to 1991, over 36,000 men and women aged 20-59 years have been examined in the Monitoring Project on Cardiovascular Disease Risk Factors in The Netherlands. Classification of the treatment status of hypertensives in this population-based study was based on self-administered questionnaires. In order to assess the accuracy of self-reported antihypertensive drug use we compared the questionnaire information with computerized pharmacy records from a sample of 372 hypertensive subjects. Most antihypertensive drugs that were mentioned in the questionnaire were present in the pharmacy medication history (93%). However, this percentage was less (76%) when a comparison was made with the calculated duration of use based on the number of units prescribed and the directions for use in the pharmacy records. About 94% of the hypertensive subjects who were using an antihypertensive drug according to the pharmacy records, also mentioned at least one antihypertensive drug in the questionnaire. Agreement between self-reported antihypertensive drug use and pharmacy records was consistently high for all classes of antihypertensive drugs. Among 321 (86%) subjects, the number and types of self-reported antihypertensive drugs were exactly the same as in the pharmacy records. In conclusion, the agreement between self-reported antihypertensive drug use and pharmacy records was high, and the self-reported questionnaire information on antihypertensive drug use can be reliably used for the classification of treatment status of hypertensive subjects in this population-based study.

Adult↗
PubMed1998

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.

Aged↗