Added therapeutic value of new drugs approved in Brazil from 2004 to 2016

This study aimed to assess the level of therapeutic innovation of new drugs approved in Brazil over 13 years and whether they met public health needs. Comparative descriptive analysis of therapeutic value assessments performed by the Brazilian Chamber of Drug Market Regulation (CMED) and the French drug bulletin Prescrire for new drugs licensed in Brazil, from January 1st 2004 to December 31st 2016. The extent to which new drugs met public health needs was examined by: checking inclusions into government-funded drug lists and/or clinical guidelines; comparing Anatomical Therapeutic Chemical Classification (ATC) codes and drug indications with the list of conditions contributing the most to the national disease burden; and assessing new medicines aimed to treat neglected diseases. 253 new drugs were approved. Antineoplastics, immunossupressants, antidiabetics and antivirals were the most frequent. Thirty-three (14%) out of 236 drugs assessed by the Brazilian chamber and sixteen (8.2%) out of 195 assessed by the French bulletin Prescrire were considered innovative. Thirty-six drugs (14.2%) were selected for coverage by the Brazilian Unified National Health System (SUS), seven of which were therapeutically innovative, and none were aimed to treat neglected disease. About 1/3 of the drugs approved aimed to treat conditions among the top contributors to Brazil's disease burden. Few therapeutically innovative drugs entered the Brazilian market, from which only a small proportion was approved to be covered by the SUS. Our findings suggest a divergence between public health needs, research & development (R&D) and drug licensing procedures.

The impact of quality-of-life data in relative effectiveness assessments of new anti-cancer drugs in European countries

PURPOSE

The aim of this study is to investigate the role of health-related quality-of-life (QoL) data in relative effectiveness assessments (REAs) of new anti-cancer drugs across European jurisdictions, during health technology assessment procedures.

METHODS

Comparative analysis of guidelines and publicly available REAs in six European jurisdictions of anti-cancer drugs approved by EMA between 2011 and 2013.

RESULTS

Fourteen anti-cancer drugs were included, adding up to 79 REAs. Whilst all guidelines state that QoL is a relevant endpoint to determine the relative effectiveness of new cancer drugs, QoL data were included in only 54% of the 79 reports and their impact on the recommendations was limited.

CONCLUSIONS

Whilst national guidelines recognize the relevance of QoL to determine the relative effectiveness of new anti-cancer drugs, this is not well-reflected in current assessments. Developing and implementing into REAs specific evidence requirements for QoL data would improve the use of this patient-centred outcome in future reimbursement and pricing decisions.

Risk of infections in patients with gout: a population-based cohort study

To investigate the risk of various types of infections (pneumonia and urinary tract infection (UTI)), and infection-related mortality in patients with gout compared with population-based controls. A retrospective cohort study was conducted using data from the UK Clinical Practice Research Datalink (CPRD). All patients with a first diagnosis of gout and aged >40 years between January 1987-July 2014, were included and matched with up to two controls. Time-varying Cox proportional hazards models were used to estimate the risk of infections and mortality. 131,565 patients and 252,763 controls (mean age: 64 years, 74% males, mean follow-up of 6.7 years) were included in the full cohort. After full statistical adjustment, the risk of pneumonia was increased (adj. HR 1.27, 95% CI 1.18 to 1.36), while the risk of UTI (adj. HR 0.99, 95% CI 0.97 to 1.01) was similar in patients compared to controls. No differences between patients and controls were observed for infection-related mortality due to pneumonia (adj. HR 1.03, 95% CI 0.93 to 1.14) or UTI (adj. HR 1.16, 95% CI 0.98 to 1.37). In conclusion, patients with gout did not have decreased risks of pneumonia, UTI or infection-related mortality compared to population-based controls.

Relative effectiveness assessments of oncology medicines for pricing and reimbursement decisions in European countries

BACKGROUND

There is a debate on the added clinical value of new, expensive, anticancer treatments. Among European decision makers, the relevance of commonly used end points in trials, especially overall survival (OS), progression-free survival (PFS) and quality of life (QoL), varies, leading to the available evidence being valued differently. This research studies the extent to which the value of end points for cancer medicines differs among European decision makers.

METHODS

We compared guidelines and relative effectiveness assessments (REAs) of medicines for pricing or reimbursement decisions in England, France, Germany, The Netherlands, Poland, and Scotland. Anticancer medicines that received marketing authorization in Europe between 2011 and 2013 with at least four available national REAs were evaluated. A total of 79 REAs were included.

RESULTS

Health technology assessment (HTA) guidelines indicate a preference for clinically and patient relevant end points such as OS and QoL above surrogate end points. Most guidelines do not specify whether PFS is considered a surrogate or patient-relevant end point. The number of REAs included per jurisdiction varied between 7 (The Netherlands) and 18 (Germany). OS data were included in all REAs and were the preferred end point by HTA agencies, but these data were not always mature or robust. QoL data are included in only 54% of the REAs, with a limited impact on the recommendations. PFS data are included in 70% of the REAs, but the extent to which HTA agencies find PFS relevant varies.

CONCLUSIONS

European decision-making on relative effectiveness of anticancer medicines is affected by a gap in requested versus available clinical evidence, mainly because the regulator is willing to accept some degree of clinical uncertainty. A multi-stakeholder debate would be essential to align concrete robust evidence requirements in oncology and a collectively shared definition for relevant clinical benefit, which will benefit patients and society in general.

Can a Joint Assessment Provide Relevant Information for National/Local Relative Effectiveness Assessments? An In-Depth Comparison of Pazopanib Assessments

BACKGROUND

In many European jurisdictions, relative effectiveness assessments (REAs) of pharmaceuticals are performed during the reimbursement decision-making process. International collaboration in the production of these assessments may prevent the duplication of information in various jurisdictions. A first pilot of a joint REA (pazopanib for the treatment of renal cell carcinoma) was published in 2011.

OBJECTIVE

The objective was to investigate how well the methods used in the joint REA match the methods used in the national/local assessments on the same topic.

METHODS

National/local assessments from European jurisdictions, available in English language, were identified through a literature search and an e-mail request to health technology assessment organizations. Data were abstracted from joint and national/local assessments using a structured data abstraction form. Results were compared for differences and similarities.

RESULTS

In total, five national/local reports were included (Belgium, England/Wales, France, The Netherlands, and Scotland). The general methods (indication, main comparator, main end points, main trial) were similar. The details of the assessment (e.g., exact wording of indication, additional comparators, additional trials included, and method of indirect comparison), however, varied. Despite these differences, the joint REA included nearly all comparators, end points, trials, and methods of analysis that were used in national/local REA reports.

CONCLUSIONS

This study has shown overlap in the methods national/local REA bodies in Europe have chosen for a pazopanib REA for renal cell carcinoma, except for the use and methods of indirect comparisons. Although some additional comparators and outcomes differed between national/local REAs, they can be captured in a comprehensive joint REA.

Safety review in 10,008 users of lansoprazole in daily practice

Purpose-Soon after the introduction of the proton pump inhibitor, lansoprazole, a 4-year observational follow-up study was started to evaluate the safety of this drug in naturally-occurring groups of patients in The Netherlands. Results of this study were compared with clinical trial data and the limited published data from observational studies.Methods- prospective, observational study in which patients with a new episode of lansoprazole use were followed during the medication period for a maximum of 2 years. All (adverse) events during use were documented by the prescriber, irrespective of possible association with lansoprazole therapy.Results- total of 805 general practitioners (GPs) and 266 specialists provided a total of 10,008 lansoprazole users with a broad range of diagnoses. Of all patients, 17.4% reported one or more adverse events. The profile and frequency of reported adverse events was consistent with results from clinical trials and other observational studies. The most frequently reported adverse events were diarrhoea, headache, nausea, skin disorders, dizziness and generalized abdominal pain/cramps. There was no new evidence of rare adverse events. Furthermore, no lansoprazole-related unlabelled adverse events of clinical significance were recorded.Conclusions- Although the patterns of use of lansoprazole in daily practice deviated to some extent from the diagnoses in the information leaflet, lansoprazole was found to have a highly acceptable safety profile in this large naturally-occurring group of users. Reporting rates were higher soon after introduction of lansoprazole before falling to a lower stable level. Copyright (c) 2000 John Wiley & Sons, Ltd.

Use of organic nitrates and the risk of hip fracture: a population-based case-control study

CONTEXT

Use of organic nitrates has been associated with increased bone mineral density. Moreover, a large Danish case-control study reported a decreased fracture risk. However, the association with duration of nitrate use, dose frequency, and impact of discontinuation has not been extensively studied.

OBJECTIVE

Our objective was to evaluate the association between organic nitrates and hip fracture risk.

METHODS

A case-control study was conducted using the Dutch PHARMO Record Linkage System (1991-2002, n = 6,763 hip fracture cases and 26,341 controls). Cases had their first admission for hip fracture, whereas controls had not sustained any fracture after enrollment. Current users of organic nitrates were patients who had received a prescription within 90 d before the index date. The analyses were adjusted for disease and drug history.

RESULTS

Current use of nitrates was not associated with a decreased risk of hip fracture [adjusted odds ratio (OR) = 0.93; 95% confidence interval (CI) = 0.83-1.04]. Those who used as-needed medication only had a lower risk of hip fracture (adjusted OR = 0.83; 95% CI = 0.63-1.08) compared with users of maintenance medication only (adjusted OR = 1.17; 95% CI = 0.97-1.40). No association was found between duration of nitrate use and fracture risk.

CONCLUSIONS

Our overall analyses showed that risk of a hip fracture was significantly lower among users of as-needed organic nitrates, when compared with users of maintenance medication. Our analyses of hip fracture risks with duration of use did not further support a beneficial effect of organic nitrates on hip fracture, although residual confounding may have masked beneficial effects.

Dyspepsia in chronic psychiatric patients

INTRODUCTION

We report on dyspeptic complaints among patients hospitalized in the long-stay ward of a general psychiatric hospital.

METHODS

A representative sample of the patients was interviewed using a structured questionnaire.

RESULTS

Eighty percent of the patients reported one or more symptoms of dyspepsia, and 68 % reported symptoms of reflux-like dyspepsia.

CONCLUSION

Significant positive associations were found for dyspepsia complaints and clozapine (OR = 3.4), laxatives (OR = 4.4), and heavy smoking (OR = 2.3).

ADR related questions received by a telephone medicines information service and ADRs received by a spontaneous ADR reporting system: a comparison regarding patients and drugs

A telephone medicines information service (telephone service) has been available in the Netherlands since 1990. Patients can anonymously and free of charge ask a pharmacist all kinds of questions related to medication use. An analysis of the questions (n=7541) received by this service in 1994 showed that 28% of the questions predominantly related to adverse drug reactions (ADRs). A comparison was made between questions concerning ADRs received by the telephone service and suspected ADRs reported to the regionalized ADR reporting system LAREB regarding characteristics of the associated patients and medicines. In both systems approximately two out of three patients were women. LAREB received relatively more reports concerning patients of 60 years and older, whereas the telephone service received relatively more questions from patients aged 20-40 years. For most classes of medicines the observed proportion of encounters at both systems differed from the expected proportion estimated by the number of prescriptions in the same year. Antidepressants in particular were more frequently encountered at both systems than expected. There were clear differences between the telephone service and LAREB regarding the classes of medicines encountered. Reports of suspected ADRs submitted to LAREB more frequently involved antibiotics, antirheumatic products, anti-asthmatics, antihypertensives and topical antifungals, whereas questions concerning ADRs received by the telephone service significantly more frequently concerned drugs acting on the central nervous system (anxiolytics/hypnotics/sedatives, antidepressants and antipsychotic drugs) and corticosteroids. We are setting up further studies to investigate whether telephone services can serve as an additional tool in postmarketing surveillance for identifying potential drug safety issues.

Reduction in the therapeutic intensity of abortive migraine drug use during ACE inhibition therapy--a pilot study

INTRODUCTION

Since a few case reports have demonstrated some beneficial effects of angiotensin converting enzyme (ACE) inhibitors in migraine prevention, we were interested in studying the impact of ACE inhibitors and angiotensin II receptor antagonists (Ang II) on the consumption of specific abortive migraine drugs and, therefore, indirectly on the frequency of migraine attacks.

METHODS

Data from a large prescription database involving 95 patients initiating a specific abortive migraine drug (ergotamine or a triptan) and subsequently treated with either an ACE inhibitor or angiotensin receptor antagonist (index group: ACE/Ang II) or diuretic (reference group) were analysed. The effects of ACE/Ang II inhibition as well as diuretic therapy on reducing the frequency of migraine attacks were assessed by measuring the mean consumption of abortive migraine drug use, in DDDs per month ('therapeutic intensity'), before, during and after ACE/Ang II or diuretic therapy. A 'therapeutic fluctuation intensity estimate' of abortive migraine drug use for all patients was likewise calculated.

RESULTS

On an individual level, the therapeutic intensity (TI) fluctuation estimate, 'during' relative to 'before' ACE diuretic therapy, was significantly larger for the ACE/Ang II group (62% reduction) than for the diuretic group (24% reduction) (p = 0.02). For patients who continued abortive migraine drug use during and after ACE/Ang II or diuretic therapy, a significantly larger reduction in this estimate was observed during ACE/Ang II inhibition (68.9%) compared to during diuretic therapy (10.5% increase) (p = 0.004). The TI fluctuation estimate, after relative to 'during', had increased by 50.3% after ACE/Ang II inhibition and had reduced by 22.2% after diuretic treatment (p = 0.1).

CONCLUSIONS

A clear reduction in the TI of abortive migraine drug use during the use of ACE inhibitors as compared to diuretic treatment was observed. Our findings may indirectly support a positive effect of ACE/Ang II inhibition on the frequency and severity of migraine attacks, as observed in other studies and reports.

Incidence and determinants of antidepressant drug use in migraine patients

The purpose of this retrospective, follow-up study was to characterise the use of antidepressant medication in a defined migraine population and evaluate the determinants thereof. Data was obtained from the PHARMO-RLS prescription database. Our migraine population (2,517 people) included patients having commenced specific migraine drugs, ergotamine or sumatriptan, for the first time from January 1 1992 to December 31 1998. The corresponding date was termed the 'index date'. Non-migraine patients, those not having used any medication specific for migraine, were selected and equally matched (n=2,517). The cumulative incidence of initiating antidepressant treatment was estimated during two-year observation periods prior to and after the index date. Several demographic and comedication characteristics were assessed as potential determinants of antidepressant drug use within the migraine population. Other determinants included usage patterns ("therapeutic intensity") of ergotamine and sumatriptan, defined as the absolute number of Defined Daily Doses (DDDs) dispensed per patient during one year prior to initiation of antidepressant therapy. A total of 300 migraine patients (11.9%) and 213 non-migraine patients (8.5%) had initiated antidepressant treatment in the two-year period prior to or in the two-year period after the index date (RR adj 1.4; 95% CI 1.2-1.7). The cumulative incidence of initiation of antidepressant treatment for the migraine population was 3.0% per year prior to and 3.2% per year after the initiation of specific migraine analgesia. The concomitant use of benzodiazepines (RR adj 4.7; 95% CI 3.5-6.3), migraine prophylactic medication (RR adj 2.1; 95% CI 1.6-2.8) and heavy therapeutic intensity use of specific migraine analgesia, defined as >/=150 DDDs per year were highly predictive of antidepressant drug use within the migraine population. In conclusion, compared to the non-migraine population, the initiation of antidepressant treatment was only slightly higher in the migraine population. A number of determinants within the latter were found to be strongly associated with antidepressant drug use, the nature of which most likely reflects an increased severity of migraine whereby therapeutic needs are higher.

Migraine prophylactic medication usage patterns in The Netherlands

This study aims to investigate usage patterns of specific migraine prophylactic medications in ergotamine and triptan patients commencing this treatment for the first time during 1 January 1992 until 31 December 1998. Usage patterns of specific migraine prophylactic drugs were evaluated for each patient by accessing data from a large prescription database and were characterized as continued, switch or stop use during the patient observation period. Several patient and medication-related factors were explored in order to identify a possible relationship with the specific usage pattern defined. Approximately 75% of the study population (n = 729) had terminated (stop or switch) prophylactic treatment after 1 year. Age < 40 years (relative risk (RR) 1.9; 95% confidence interval (CI) 1.2-3.2) and the concomitant use of non-steroidal anti-inflammatory drugs (RR 3.2; 95% CI 1.2-5.5) or specific abortive migraine drugs resulted in a faster onset of treatment modification (switch). Overall, migraine prophylactic treatment is used for a relatively short period, probably attributable to the common limitations associated with migraine prophylaxis, such as poor compliance and/or limited therapeutic efficacy. Patterns of use can be influenced by a variety of factors, including age, type of prescriber and certain co-medication. Patient interview studies are required to clarify these issues further.

Single use of sumatriptan: a patient interview study

OBJECTIVE

To investigate the possible reasons associated with the use of a single prescription of sumatriptan.

BACKGROUND

A few population-based studies concerning the usage patterns of sumatriptan have revealed a relatively high incidence (approximately 40%) of sumatriptan users who utilize only a single prescription of the drug.

DESIGN AND METHODS

Using automated prescription data from 11 community pharmacies, we identified single and multiple sumatriptan prescription recipients. The data were collected from May 1, 1998, to April 30, 2000. Several patient- and medication-related variables possibly associated with single recipiency of sumatriptan were analyzed. In addition, single recipients of sumatriptan were invited for an interview and asked a number of questions related to their clinical status and their experience with the medication.

RESULTS

Four hundred ninety-five, first-time users of sumatriptan were identified during the patient selection period, of whom 38% were single recipients of sumatriptan. Of the latter, 102 patients were considered eligible for interview. Reasons for terminating treatment after only 1 prescription included: inefficacy and/or occurrence of side effects, 78% (n=79); uncertain diagnosis of migraine, 39.2% (n=40); and reduction in headache frequency, 33.3% (n=34). Almost half of the population had terminated treatment without having consulted their physician. More than half relied upon the use of over-the-counter (OTC) analgesics after having tried sumatriptan. Compared to multiple users of sumatriptan, single recipients were far less likely to have used another form of migraine treatment prior to (odds ratio, 0.35; [95% confidence interval, 019 to 0.67]) and after (odds ratio, 0.34 [95% confidence interval, 0.19 to 0.63]) initiating sumatriptan. Furthermore, single recipients had demonstrated an increased tendency towards benzodiazepine use prior to receiving sumatriptan (odds ratio, 1.80 [95% confidence interval, 1.00 to 3.28]).

CONCLUSIONS

Single use of a sumatriptan prescription reveals some issues that may impact negatively the provision of effective migraine management. These include: rapidly developing dissatisfaction with the treatment provided and a lower tendency to seek out medical care. Our results also suggest that the drug may be used (inappropriately) as a diagnostic tool.

The effectiveness of hydroxy-methylglutaryl coenzyme A reductase inhibitors (statins) in the elderly is not influenced by apolipoprotein E genotype

We aimed to assess whether the effectiveness of statins in the prevention of myocardial infarction, stroke and total mortality is influenced by apolipoprotein E (apoE) genotype in an elderly population. We used data from the Rotterdam Study, a prospective population-based cohort study in the Netherlands which started in 1990 and included 7983 subjects aged 55 years and older. Subjects who were treated with cholesterol lowering drugs at baseline or with a serum total cholesterol > or = 6.5 mmol/l at baseline were included. We compared the incidence of myocardial infarction, stroke and total mortality in subjects who received > or = 2 years of statin treatment with that in subjects who had been treated for less than 2 years, and in untreated subjects, using a Cox proportional hazard model with cumulative statin use defined as time-dependent covariates. The adjusted relative risk of all-cause mortality was 0.79 [95% confidence interval (CI) 0.51-1.22] and of myocardial infarction and stroke 0.50 (95% CI 0.28-0.91) for subjects treated with statins for > or = 2 years compared to untreated subjects. The adjusted relative risks for subjects with the epsilon4 allele were 0.91 (95% CI 0.45-1.84) for all-cause mortality and 0.63 (95% CI 0.23-1.78) for myocardial infarction and stroke. In subjects without the epsilon4 allele, adjusted relative risks were 0.71 (95% CI 0.41-1.24) for all-cause mortality and 0.46 (95% CI 0.22-0.95) for myocardial infarction and stroke. We found a protective effect of statins on the risk of myocardial infarction and stroke that was independent of apoE genotype. The protective effect of statins on total mortality was not statistically significant, but did not seem to differ between subjects with different apoE genotypes.

Incidence and determinants of migraine prophylactic medication in the Netherlands

OBJECTIVE

To estimate and examine the incidence and determinants of initiation of migraine-prophylactic therapy as well as the corresponding drug of choice over a period of 5 years following the use of specific abortive migraine drugs.

METHODS

By accessing data from a large prescription database, an identification of patients treated with ergotamine or a triptan from 1 January 1994 to 31 December 1998 was made. The cumulative incidence of initiation of migraine-prophylactic drugs (beta-blockers, serotonin antagonists, specific calcium antagonists, amitriptyline, clonidine and valproic acid) was estimated in patients following the use of ergotamine or a triptan. An assessment of the migraine-prophylactic drug of first choice was also performed. A few baseline determinants were analysed to highlight a possible association with the initiation of prophylactic therapy: age, gender, type of abortive migraine drug use and year of prophylaxis. Additional determinants included the analysis of drug-utilisation patterns, such as the consumption and switch patterns of abortive migraine drug use as well as co-medication use prior to prophylaxis. For this particular analysis a reference group (patients not having commenced prophylaxis) was selected from the initial study population.

RESULTS

After having satisfied eligibility criteria, a total of 3999 first-time users of ergotamine and triptans were included of whom 479 (12%) had initiated migraine-prophylactic therapy. This corresponded to an incidence density of 6.0 per 100 person-years and was highest for patients younger than 45 years and for multiple abortive migraine drug users. The incidence fell considerably from 12.0 person-years in 1994 to 5.1 person-years in 1998. More than half of the patients had been prescribed a beta-blocker as the migraine-prophylactic drug of first choice by both general practitioners and neurologists. The use of antidepressants and/or benzodiazepines and oral contraceptives was significantly higher in patients starting prophylaxis compared with those who did not. The consumption of abortive migraine drug use (4.0 defined daily doses per month vs 3.7 defined daily doses per month), and switch patterns (27.1% vs 30.9%) were similar for patients starting and not starting prophylaxis.

CONCLUSION

The overall incidence of initiation of migraine-prophylactic therapy following the use of abortive migraine analgesics was 6.0% per year and fell considerably during 5 years of the study. Beta-blockers were the migraine-prophylactic drugs of first choice for general practitioners and neurologists. In our study we could not determine any factors clearly associated with the initiation of migraine prophylaxis besides prior use of antidepressants and benzodiazepines. A future assessment of the usage patterns of migraine-prophylactic drugs may provide detailed information concerning the effectiveness and tolerability.

The Dutch cohort of sildenafil users: baseline characteristics

OBJECTIVE

To identify a Dutch cohort of sildenafil users and describe their baseline characteristics.

PATIENTS AND METHODS

Each pharmacy in The Netherlands (n = 1571) was asked to identify prospectively the first 20 sildenafil prescriptions in their pharmacy over 1 year, and to complete and return a registration form. The collected data included patient characteristics, the details of the sildenafil prescription (date, prescriber, number of prescriptions, dosing), and the use of co-medication by the patient in the year preceding the sildenafil prescription.

RESULTS

Data were collected from 4460 sildenafil prescriptions during the year under study, relating to 3477 individual patients. Most of the cohort had cardiovascular morbidity or diabetes. Sildenafil seems to have been used by a new, previously untreated population of patients with erectile dysfunction. In addition, 69 men were identified who could have been using nitrates and sildenafil concomitantly.

CONCLUSION

A cohort of patients using sildenafil was identified and characterized; they appeared to be representative of sildenafil users in The Netherlands. This cohort will be followed prospectively to evaluate the medical status (particularly cardiovascular) of the patients with time.

Psychotropic drug use in intellectually disabled group-home residents with behavioural problems

Little is known about psychiatric and behavioural factors associated with psychotropic drug use and how appropriately these drugs are prescribed in settings for people with intellectual disabilities. The aim of this study was to measure the point prevalence of psychotropic drug use in a problem-behaviour group (PBG) consisting of intellectually disabled residents of group homes compared to a random group (RG), and to gain insight in possible factors that are associated with group membership. From all group homes in the Netherlands, 573 problematic residents were selected by the staff (one resident from each home) and 1479 residents were randomly sampled from all of the homes. Mental health problems were measured using the Reiss Screen for Maladaptive Behaviour and the Psychopathology Instrument for Mentally Retarded Adults. The response rate in the PBG was 68.9 % and in the RG 71.7 %. Psychotropics (excluding anticonvulsants) were used by 52.6 % of the PBG and by 22.8 % of the RG. Young age, psychotic, anxiety, and aggression symptoms were significantly associated with the PBG, as was the use of antipsychotics and antidepressants. The PBG more often used multiple (three or more) drugs (17.3 %) than the RG (7.3 %). A low prevalence of antidepressants or mood stabilisers, antipsychotics, and anxiolytics was found in residents with affective, psychotic, or anxiety symptoms. We conclude that psychotropic drug use in the PBG compared to the RG was high. It is likely that the group-home staff finds it difficult to deal with young people with socially disruptive behaviour, which is underlined by our finding of high prevalence of antipsychotics and multiple-drug therapy in the PBG. Finally, our findings suggest that a considerable number of residents with psychiatric or behavioural symptoms are undertreated.

Epidemiology of fractures in England and Wales

Records from the General Practice Research Database were used to derive age- and gender-specific fracture incidence rates for England and Wales during the period 1988-1998. In total, 103,052 men and 119,317 women in the sample of 5 million adults sustained a fracture over 10.4 million and 11.2 million person-years (py) of follow-up. Among women, the most frequent fracture sites were the radius/ulna (30.2 cases per 10,000 py) and femur/hip (17.0 per 10,000 py). In men, the most common fracture was that of the carpal bones (26.2 per 10,000 py); the incidence of femur/hip fracture was 5.3 per 10,000 py. Varying patterns of fracture incidence were observed with increasing age; whereas some fractures became more common in later life (vertebral, distal forearm, hip, proximal humerus, rib, clavicle, pelvis), others were more frequent in childhood and young adulthood (tibia, fibula, carpus, foot, ankle). The lifetime risk of any fracture was 53.2% at age 50 years among women, and 20.7% at the same age among men. Whereas fractures of the proximal femur and vertebral body were associated with excess mortality over a 5 year period following fracture diagnosis among both men and women, fractures of the distal forearm were associated with only slight excess mortality in men. This study provides robust estimates of fracture incidence that will assist health-care planning and delivery.

Spontaneous lapses in dosing during chronic treatment with selective serotonin reuptake inhibitors

BACKGROUND

In previous research, lapses in dosing of paroxetine or sertraline were associated with significantly more discontinuation symptoms and deterioration of depressive symptomatology compared with fluoxetine.

AIMS

To evaluate dosing lapses in patients chronically treated with selective serotonin reuptake inhibitors (SSRIs) in uncontrolled circumstances.

METHOD

In a prospective observational study we evaluated compliance data in chronic users of SSRIs using electronic drug exposure monitors.

RESULTS

During a 3-month follow-up we found that 50/69 (72.5%) patients missed at least one dosing day and 20/69 (29.0%) missed two or more consecutive days.

CONCLUSIONS

About 30% of patients treated with short-acting SSRIs had dosing lapses of 2 or more days, which, as described in prior studies, is long enough to result in clinically relevant deterioration of mental status.

Pyrazinamide use as a method of estimating under-reporting of tuberculosis

OBJECTIVE

To develop a method of validating the notification of active tuberculosis by physicians in the Netherlands.

METHOD

The chemotherapeutic agent pyrazinamide was used as a marker for the occurrence of tuberculosis. On the basis of defined daily doses (DDD) of pyrazinamide dispensed to out-patients, an estimate was made of the number of patients with tuberculosis in the Netherlands in the period 1994-1998. DDD is a technical unit of measurement and does not necessarily reflect the recommended or actual dose used. Usually it is based on the average dosage per day for the main indication in adults with normal organ function. The Dutch Drug Information Project (GIP) of the Health Care Insurance Board (CVZ) provided the DDD data. Based on the notification of tuberculosis patients to the Netherlands Tuberculosis Register (NTR) we calculated how much pyrazinamide (measured in DDDs) these patients would have used depending on their body weight.

RESULTS

The number of DDDs prescribed according to the GIP pharmacy records differed by only 8% from the number of DDDs calculated on the basis of notification to the NTR; 6889 patients should have been registered instead of 6349.

CONCLUSION

The close correlation between the use of pyrazinamide as measured by the GIP and NTR provides strong evidence that in the Netherlands tuberculosis is reported in conformity with the guidelines for notifiable diseases. The method was simple to apply and may deserve follow-up in other countries.

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.

Determinants of multiple psychotropic drug use in patients with mild intellectual disabilities or borderline intellectual functioning and psychiatric or behavioral disorders

Prevalence rates of psychotropic drug use in people with intellectual disabilities are high and pharmacotherapy is often attempted with multiple drugs. The presence of disruptive behavior is an important factor associated with the use of psychotropic drugs in this population. We wanted to gain insight into prevalence and determinants of multiple psychotropic drug use among patients with mild intellectual disabilities or borderline intellectual functioning with psychiatric or behavioral disorders. Therefore, data on psychotropics and possible determinants of use were retrospectively collected during 1992-1997 in a specialized closed ward of a Dutch general psychiatric hospital. We defined multiple drug use as concomitant prescription (regular or as needed) of a combination of benzodiazepines/tranquilizers/antipsychotics/anticonvulsants/anti-depressants. Multiple drug use, seen in 48% of the patients, was associated with a long duration of stay, psychosis, aggressive, bizarre, attention-seeking behavior and involuntary measures. We conclude that it is likely that difficulties in the management of socially disruptive behavior are often countered by multiple drug prescription.

Determinants of signal selection in a spontaneous reporting system for adverse drug reactions

AIMS

Detection of new adverse drug reactions (ADR) after marketing is often based on a manual review of reports sent to a Spontaneous Reporting System (SRS). Among the many potential signals that are identified, only a limited number are important enough to require further attention. The goal of this study is to gain insight into factors contributing to the selection and dissemination of possible signals originating from the SRS maintained by the Netherlands Pharmacovigilance Foundation.

METHODS

In a case control design, all signals (n = 42) disseminated to the Medicines Evaluation Board from the second quarter of 1997 until the third quarter of 2000, which could be expressed as a combination of a single ATC code and a single WHO preferred term, were included. For each case, four controls were matched in time. Logistic regression analysis was used to investigate the influence of various factors, such as the fact whether the ADR or drug is new, the strength of the association, the seriousness of the reaction and the documentation of the reports.

RESULTS

Multivariate analysis showed that the presence of a 'serious report' (Odds Ratio 3.8, 95% CI 1.3, 11.0), a WHO 'critical term' (OR 4.7, 95% CI 1.8, 13), the ADR being unlabelled (OR 6.1, 95% CI 2.3, 16) and the presence of a disproportionate association (OR 3.5, 95% CI 1.4, 8) were all independently associated with signal selection. The number of reports and the time after marketing of the drug had no influence.

CONCLUSIONS

This study showed that selection of signals is based on both qualitative and quantitative aspects. Knowledge of these factors may improve the efficiency of the underlying signal selection process.

The association between antihypertensive drug therapies and plasma lipid levels in the general population

OBJECTIVE

To assess the association between different antihypertensive drug regimens and plasma lipid levels in the general population.

METHODS

The Monitoring Project on Cardiovascular Risk Factors was conducted from 1987 to 1991 as a cross-sectional study in The Netherlands. Antihypertensive drug-users and untreated hypertensives were selected. After exclusion of users of cholesterol-lowering drugs 2997 subjects remained for the analysis. The plasma lipid concentrations of the users and non-users of antihypertensives were compared by multiple linear regression.

RESULTS

In the univariate analysis patients using beta-blockers had lower high-density lipoprotein (HDL) concentrations (1.13 mmol/l, P < 0.05) and higher cholesterol ratios (5.74, P < 0.05) than untreated hypertensives (Total cholesterol = 6.07 mmol/l, HDL = 1.20 mmol/l and ratio = 5.44). Patients using diuretics had higher total cholesterol levels (6.34 mmol/l) and higher HDL levels (1.26 mmol/l) compared to untreated hypertensives. After adjustment for possible confounders these differences were smaller and no longer statistically significant. After adjustment we found a significant lower HDL cholesterol (mean difference of -0.10 mmol/l, P < 0.05) for users of a combination of a beta-blocker and a diuretic.

CONCLUSIONS

Although randomised, controlled trials have demonstrated that antihypertensive drugs may influence plasma lipid levels we observed no substantial association for single antihypertensive drug therapy in the general population. The combination of a diuretic and a beta-blocker was associated with a worse lipid profile.

Reduction in the intensity of abortive migraine drug use during coumarin therapy

OBJECTIVE

To investigate the impact of coumarin therapy on migraine attack frequency.

BACKGROUND

Sporadic case reports and clinical studies have described beneficial effects of coumarin therapy on migraine severity.

DESIGN AND METHODS

A retrospective follow-up study based on a prescription database covering a population of 450 000 was conducted. All patients using an abortive migraine drug (ergotamine or sumatriptan) and subsequently treated with either coumarin (index group) or low-dose acetylsalicylic acid (control group) were analyzed. The impact of coumarin and low-dose acetylsalicylic acid on the frequency of migraine attacks was assessed by measuring the intensity of ergotamine and sumatriptan use, in defined daily doses per month per patient, before and during coumarin or acetylsalicylic acid treatment. In addition, a "therapeutic intensity reduction" was determined for each patient.

RESULTS

The study population consisted of 92 patients; 35% had been prescribed coumarin and 65% had been prescribed low-dose acetylsalicylic acid after the initiation of ergotamine or sumatriptan. Two thirds of the study population was treated with ergotamine. Overall, ergotamine and sumatriptan use for the coumarin cohort decreased from 6.4 defined daily doses per month prior to coumarin treatment to 3.0 defined daily doses during coumarin treatment, compared with a reduction from 5.2 defined daily doses per month to 4.4 defined daily doses per month for the low-dose acetylsalicylic acid cohort (P>.05). The therapeutic intensity of ergotamine and sumatriptan use was significantly decreased by 40% for the coumarin cohort, compared with 4.7% for the low-dose acetylsalicylic acid cohort (P=.004).

CONCLUSIONS

We observed that coumarin treatment was clearly associated with a reduction in the therapeutic intensity of abortive migraine drug use in comparison with low-dose aspirin treatment. This suggests that, overall, the coumarin cohort had experienced a substantial reduction in the frequency of migraine attacks during anticoagulation treatment. Our findings, as well as those of others, justify a controlled clinical trial to further establish the effects of coumarin therapy on migraine severity and its possible role in the prophylactic management of patients suffering from migraine.

Cardiovascular drug use and hospitalizations attributable to type 2 diabetes

OBJECTIVE

To investigate cardiovascular drug use and hospitalizations attributable to type 2 diabetes from 1 year before until 6 years after the start of oral antidiabetic therapy.

RESEARCH DESIGN AND METHODS

In this cohort study, 2,584 patients with type 2 diabetes were selected from the PHARMO Record Linkage System, comprising pharmacy records and hospitalizations for all 320,000 residents of six Dutch cities. Patients with type 2 diabetes were identified as incident oral antidiabetic drug users between 1992 and 1997. Nondiabetic subjects were 1:1-matched for age, sex, pharmacy, and index date and received no insulin, oral antidiabetic drugs, or glucose-testing supplies.

RESULTS

Patients with type 2 diabetes were more likely to use cardiovascular drugs (RR 1.28 [95% CI 1.23-1.34]) and to be hospitalized because of cardiovascular diseases (1.54 [1.33-1.78]) after the start of oral antidiabetic therapy than nondiabetic subjects. Differences between patients with type 2 diabetes and nondiabetic subjects lessened from 1 year before until 6 years after the start of oral antidiabetic therapy, reflected by decreasing attributable risks for diuretics, beta-blockers, calcium channel blockers, and cardiac and antithrombotic drugs. The difference in use of angiotensin-converting enzyme inhibitors and lipid-lowering drugs increased. Cardiovascular hospitalizations attributable to type 2 diabetes were approximately 50% in the years close to the start of oral antidiabetic treatment and decreased to approximately 33% in the following years.

CONCLUSIONS

Although cardiovascular drug use and hospitalizations remained increased in patients with type 2 diabetes after the start of oral antidiabetic therapy, cardiovascular drug use attributable to type 2 diabetes decreased after the start of oral antidiabetic therapy, especially beta-blockers, whereas cardiovascular hospitalizations first decreased and then stabilized.

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.

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.

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.

Patterns of ergotamine and sumatriptan use in the Netherlands from 1991 to 1997

The objective of this study was to assess usage patterns of ergotamine and sumatriptan over a period of 6 years, primarily to evaluate the impact that sumatriptan has had on the prescription of ergotamine. This study used ergotamine and sumatriptan prescription data representing inhabitants of eight cities in the Netherlands and covering the period of 1991-1997. The yearly incidence of new users between 1991 and 1997 was estimated for both drugs as well as for the drug of first choice to be prescribed to patients initiating specific abortive migraine treatment with either ergotamine or sumatriptan. Intra-individual ergotamine and sumatriptan usage patterns, characterized by single (incidental), continuous (rate of retention) or switch use, were examined for five patient cohorts, each for a follow-up period of 1 year. During the year of sumatriptan introduction (1991-1992), the overall incidence of new use for both drugs was highest (5.4 per 1000 inhabitants). Hereafter, a substantial reduction of more than 50% was observed. From 1992 to 1996, the yearly incidence of ergotamine first-time use was significantly higher than that of sumatriptan and up to 1996 ergotamine was more than twice as likely than sumatriptan to be prescribed to patients initiating specific abortive treatment. Hereafter, sumatriptan was as likely as ergotamine to be prescribed as the drug of first choice, which coincided with the full reimbursement of sumatriptan tablets. Overall, neurologists were more likely than general practitioners (GPs), to prescribe sumatriptan as the drug of first choice. Approximately half of the total study population were identified as single-time users. This phenomonen occurred more frequently in the ergotamine cohorts. The sumatriptan cohorts displayed a slight yet significant stronger retention rate compared with the ergotamine cohorts. The overall impact of sumatriptan on ergotamine use in The Netherlands was marginal, predominantly due to GP's adherence to migraine treatment guidelines and reimbursement policies concerning sumatriptan tablets. Overall, incidental use was relatively high and may reflect the reported difficulties in diagnosing migraine, lack of patient-doctor consultation, or that anticipated benefits of the drug were not achieved. Further study is required to clarify these issues.

Public health impact of adverse bone effects of oral corticosteroids

AIMS

The objective of this study was to estimate the number of fractures attributed to oral corticosteroid use.

METHODS

Information was obtained from the General Practice Research Database which contains medical records of general practitioners in the UK. The total number of corticosteroid-related fractures during a course of treatment was estimated using the formula for attributable risk among the exposed.

RESULTS

A total of 244 235 patients was prescribed an oral corticosteroid. The rate of hip fractures increased exponentially with age in both males and females. The excess number of hip fracture cases among females aged 85 years or older using 7.5 mg prednisolone per day or more was 1.4 cases per 100 patients per year. About 47% of all hip and 72% of all vertebral fractures that occurred can be attributed to oral corticosteroid use. Among 10 000 female users of higher doses, 99.7 nonvertebral, 31.6 hip and 45.8 vertebral fractures can be attributed to use of oral corticosteroids.

CONCLUSIONS

The targeting of high-risk patients will be important for implementing preventative strategies in a cost-effective manner.

Factors associated with non-response in proton pump inhibitor users: a study of lansoprazole therapy

BACKGROUND

Proton pump inhibitors (PPI) demonstrate high healing rates of 85-98% in clinical trials. Due to the limited knowledge regarding response and non-response to lansoprazole in daily practice and for the reason that resistance to PPIs is scarce, we investigated factors possibly associated with non-response.

METHODS

Data were used from a prospective, open label, observational follow-up study in which 10,008 lansoprazole users were followed over time. The study was designed according to the SAMM guidelines. A matched nested case-control design was used to compare non-responding (cases) and responding (controls) lansoprazole users. Non-response was defined as worsening or non-improvement of symptoms at the first evaluation after at least 8 weeks of use, response as disappearance or improvement of symptoms within 8 weeks of use. Controls were matched for the evaluating physician.

RESULTS

A total of 186 non-responders and 372 responders to PPI treatment were identified as cases and controls. Age of over 60 years, heavy smoking and previous use of PPIs were significantly more common in non-responding patients compared with responding patients. There were no differences found between the reported diagnosis regarding response.

CONCLUSION

In daily clinical practice, previous use of PPIs, heavy smoking and an age > 60 years were significantly associated with non-response to treatment with lansoprazole. Previous use of PPIs in non-responding patients might suggest resistance to PPIs. The knowledge that non-response drives non-response may encourage physicians to follow PPI users with previous PPI use more closely.

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.

Pharmacoepidemiology and gastroenterology: a close couple

The discipline of pharmacoepidemiology has always been strongly linked with the problem of gastrointestinal injury caused by non-steroidal anti-inflammatory drugs, and has led to a close liaison between gastroenterology and pharmacoepidemiology.

AIM

This paper discusses three important areas of pharmacoepidemiological interest relevant to gastroenterologists: confounding by indication and channeling bias, drug exposure patterns, and postmarketing surveillance studies. (i) Drug prescribing is associated with a patient's prognosis and disease status, called indication for treatment. These patient disease characteristics can drive drug channeling in risk populations and create confounded drug-effect associations. (ii) Drug exposure is the result of the 'natural' experiment of pharmacotherapy over time. Reliable information on the time-sequence of events in relation to drug exposure is required to evaluate both beneficial and adverse effects of drug therapy. (iii) Postmarketing surveillance studies provide intensive learning about drug effects when large spectra of patients with various medical backgrounds, prognoses, co-morbidity, and the like, are exposed to the drug. Information on drug use and patient outcomes in 'real life' populations is necessary to bridge normal practice experiments with randomized clinical trials.

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.

Determinants of change in the intention to use benzodiazepines

OBJECTIVE

To examine attitudes and beliefs associated with changes in the intention to use benzodiazepines during the six-month period after first benzodiazepine use.

DESIGN

Population-based 6-month follow-up with 3 measurement points (baseline, 2 weeks after inclusion, 6 months after inclusion).

SETTING

Starting or initial benzodiazepine users were included during a period of 4 months from November 1994 in the only pharmacy of a Dutch community of 13,500 people.

MEASURES

Variables proposed by the Model of Planned Behaviour and the Health Belief Model. Drug exposure data from automated pharmacy records.

RESULTS

At baseline, the intention to use benzodiazepines was primarily predicted by the perceived norm of the general practitioner regarding benzodiazepine use, and by the participants' own attitudes. After fourteen days, the determinants of change in the intention to use benzodiazepines were the initially perceived norm of the general practitioner and the change in the severity of participants' illnesses. After six months, the change in the severity of the illness and the perceived health benefits of benzodiazepines at the time of inclusion were the main determinants of the change in the intention to use benzodiazepines between the second and third measurement point. The intention to use benzodiazepines showed a decrease during follow-up. The three intention measures were significant predictors of actual benzodiazepine use during the year following baseline assessment.

CONCLUSION

The study sheds light on interesting determinants of decrease or increase in the intention to use during the six-month period after first benzodiazepine use.

Use of inhaled corticosteroids and risk of fractures

Treatment with systemic corticosteroids is known to increase the risk of fractures but little is known of the fracture risks associated with inhaled corticosteroids. A retrospective cohort study was conducted using a large UK primary care database (the General Practice Research Database [GPRD]). Inhaled corticosteroid users aged 18 years or older were compared with matched control patients and to a group of noncorticosteroid bronchodilator users. Patients with concomitant use of systemic corticosteroids were excluded. The study comprised 170,818 inhaled corticosteroid users, 108,786 bronchodilator users, and 170,818 control patients. The average age was 45.1 years in the inhaled corticosteroid, 49.3 years in the bronchodilator, and 45.2 years in the control groups. In the inhaled corticosteroid cohort, 54.5% were female. The relative rates (RRs) of nonvertebral, hip, and vertebral fractures during inhaled corticosteroid treatment compared with control were 1.15 (95% CI, 1.10-1.20), 1.22 (95% CI, 1.04-1.43), and 1.51 (95% CI, 1.22-1.85), respectively. No differences were found between the inhaled corticosteroid and bronchodilator groups (nonvertebral fracture RR = 1.00; 95% CI, 0.94-1.06). The rates of nonvertebral fractures among users of budesonide (RR = 0.95; 95% CI, 0.85-1.07) and fluticasone propionate (RR = 1.03; 95% CI, 0.71-1.49) were similar to the rate determined for users of beclomethasone dipropionate. We conclude that users of inhaled corticosteroids have an increased risk of fracture, particularly at the hip and spine. However, this excess risk may be related more to the underlying respiratory disease than to inhaled corticosteroid.

Association between terbinafine and arthralgia, fever and urticaria: symptoms or syndrome?

PURPOSE

The antifungal agent terbinafine has been approved for marketing in The Netherlands since 1992. Adverse drug reactions (ADRs) may occur in about 10% of the patients, the majority gastrointestinal disorders and skin reactions. Since the introduction of terbinafine, the Netherlands Pharmacovigilance Foundation Lareb received eight reports of arthralgia during the use of this drug. In four reports the additional presence of skin reactions was mentioned, two of these reports concerned urticaria. Two patients who reported arthralgia also had a fever. These reports were described in more detail, and analysed statistically in order to determine whether symptoms are interrelated.

METHODS

All reports with known gender and a reporting date between 1 March 1992 and 1 January 1999, concerning patients older than 10 years, were included. The extent to which the symptoms urticaria, fever and arthralgia were interrelated was examined by logistic regression modelling.

RESULTS

Case series as well as the results of the statistical analysis show a clustering of symptoms among reports of patients using terbinafine. Both urticaria and arthralgia were statistically significantly associated with reports on terbinafine compared to all other reports in the database.

CONCLUSION

The findings might point towards a clustering of these symptoms in patients using terbinafine. Possibly these symptoms have a shared aetiology, presumably an immunological reaction.

Prescribing patterns in patients using new antidepressants

AIMS

To study possible selective prescribing ('channelling') we compared characteristics of patients using the SSRI sertraline with patients using longer available SSRIs.

METHODS

An observational cohort study in 1251 patients being prescribed an SSRI.

RESULTS

In contrast to other studies, we found no evidence for channeling of sertraline. Sertraline was mainly prescribed for the labelled indication (depressive disorder), while older SSRIs were more often prescribed also for other indications. Time on the market was inversely associated to the proportion of patients treated for depressive disorder.

CONCLUSIONS

We found no evidence for channeling of sertraline compared with prescribing patterns of older SSRIs.

Costs and effects of combining stenting and abciximab (ReoPro) in daily practice

AIM

The combined use of stents and abciximab in percutaneous coronary intervention has been evaluated in the EPISTENT trial. However, the clinical and economic findings in trials are not necessarily generalisable to a general population setting. We conducted a study in daily clinical practice comparing stented and non-stented patients undergoing coronary angioplasty with abciximab administration. Furthermore, we compare our results with the findings of the EPISTENT trial.

METHODS

From 1995 to 1999, refractory unstable patients scheduled for angioplasty and receiving abciximab in a Dutch regional hospital were followed prospectively for 6 months. Total costs were considered in addition to 2 composite clinical endpoints: (1) death or myocardial infarction (MI); and (2) death, MI, or any revascularisation procedure (major adverse cardiac events, MACE).

RESULTS

Stented patients (N=101) experienced less MACE than non-stented patients (N=83) (6.9% vs. 16.9%, OR=0.37, P=0.04). The total costs were similar for stented and non-stented patients (EUR 7 844 vs. EUR 7 904, P=0.93). Adjustment for baseline characteristics yielded similar results, although significance subsided. The relative risk reduction of 44% that we found, closely resembles the 42% that was found in the EPISTENT trial.

CONCLUSIONS

In everyday practice, as in the EPISTENT trial, the addition of a stent to abciximab treatment does seem to reduce the risk of MACE by about 40% at no additional costs.

Antihypertensive drug therapies and the risk of ischemic stroke

BACKGROUND

The relative effectiveness of various antihypertensive drugs with regard to the reduction of stroke incidence remains uncertain.

OBJECTIVE

To assess the association between first ischemic stroke and use of antihypertensive drugs.

METHODS

A population-based case-control study was performed among enrollees of the Group Health Cooperative of Puget Sound. Case patients included pharmacologically treated hypertensive patients who sustained a first ischemic stroke (fatal or nonfatal; n = 380) between July 1, 1989, and December 31, 1996. Control subjects were a random sample of treated hypertensive enrollees without a history of a stroke (n = 2790). Medical record review and a telephone interview of consenting survivors were used to collect information on risk factors for stroke. Computerized pharmacy records were used to assess antihypertensive drug use.

RESULTS

Among 1237 single-drug users with no history of cardiovascular disease, the adjusted risk of ischemic stroke was higher among users of a beta-blocker (risk ratio [RR], 2.03; 95% confidence interval [CI], 1.05-3.94), calcium channel blocker (RR, 2.30; 95% CI, 1.16-4.56), or angiotensin-converting enzyme inhibitor (RR, 2.79; 95% CI, 1.47-5. 27) than among users of a thiazide diuretic alone. Among 673 single-drug users with a history of cardiovascular disease, the RRs were 1.22 (95% CI, 0.63-2.35), 1.18 (95% CI, 0.59-2.33), and 1.45 (95% CI, 0.70-3.02) among users of a beta-blocker, calcium channel blocker, and angiotensin-converting enzyme inhibitor, respectively, compared with users of a thiazide diuretic alone.

CONCLUSIONS

In this study of pharmacologically treated hypertensive patients, antihypertensive drug regimens that did not include a thiazide diuretic were associated with an increased risk of ischemic stroke compared with regimens that did include a thiazide. These results support the use of thiazide diuretics as first-line antihypertensive agents.

The interface between pharmacoepidemiology and pharmacogenetics

One of the most challenging areas of research in pharmacoepidemiology is to understand why individuals respond differently to drug therapy, both in terms of beneficial and adverse effects. Pharmacogenetics focuses on the question to what extent variability in genetic make-up is responsible for these observed differences. Pharmacoepidemiologic research can contribute to pharmacogenetics by explaining the observed variability in drug response in 'real life' patient populations with known polymorphisms in their genetic profile. Genetic pharmacoepidemiologists also are interested in the distribution of polymorphisms and correlated frequencies of responders and non-responders in the general population, and in searching for unknown genetic links to variability in drug response. In the future, we will probably have fewer drugs that suit all individuals. Genetic pharmacoepidemiology is going to play a major role in the development and evaluation of the concept of 'tailor-made' pharmacotherapy.

Detecting drug-drug interactions using a database for spontaneous adverse drug reactions: an example with diuretics and non-steroidal anti-inflammatory drugs

OBJECTIVE

Drug-drug interactions are relatively rarely reported to spontaneous reporting systems (SRSs) for adverse drug reactions. For this reason, the traditional approach for analysing SRS has major limitations for the detection of drug-drug interactions. We developed a method that may enable signalling of these possible interactions, which are often not explicitly reported, utilising reports of adverse drug reactions in data sets of SRS. As an example, the influence of concomitant use of diuretics and non-steroidal anti-inflammatory drugs (NSAIDs) on symptoms indicating a decreased efficacy of diuretics was examined using reports received by the Netherlands Pharmacovigilance Foundation Lareb.

METHODS

Reports received between 1 January 1990 and 1 January 1999 of patients older than 50 years were included in the study. Cases were defined as reports with symptoms indicating a decreased efficacy of diuretics, non-cases as all other reports. Exposure categories were the use of NSAIDs or diuretics versus the use of neither of these drugs. The influence of the combined use of both drugs was examined using logistic regression analysis.

RESULTS

The odds ratio of the statistical interaction term of the combined use of both drugs was increased [adjusted odds ratio 2.0, 95% confidence interval (CI) 1.1-3.7], which may indicate an enhanced effect of concomitant drug use.

CONCLUSION

The findings illustrate that spontaneous reporting systems have a potential for signal detection and the analysis of possible drug-drug interactions. The method described may enable a more active approach in the detection of drug-drug interactions after marketing.

Oral corticosteroids and fracture risk: relationship to daily and cumulative doses

OBJECTIVE

This study examined the effects of daily and cumulative oral corticosteroid doses on the risk of fractures.

METHODS

Information was obtained from the General Practice Research Database, which contains medical records of general practitioners in England and Wales. The study included 244 235 oral corticosteroid users and 244 235 controls.

RESULTS

Patients taking higher doses (at least 7. 5 mg daily of prednisolone or equivalent) had significantly increased risks of non-vertebral fracture [relative rate (RR)=1.44, 95% confidence interval (CI) 1.34-1.54], hip fracture (RR=2.21, 95% CI 1.85-2.64) and vertebral fracture (RR=2.83, 95% CI 2.35-2.40) relative to patients using oral corticosteroids at lower doses (less than 2.5 mg per day). Fracture risk was also elevated among people with higher cumulative exposure to oral corticosteroids over the study period, but this effect was almost wholly removed by adjustment for daily dose, age, gender and other confounding variables.

CONCLUSIONS

These findings suggest that the adverse skeletal effects of oral corticosteroids manifest rapidly and are related to daily dose. The level of previous exposure to oral corticosteroids was not a strong determinant of the risk of fracture. Preventive measures against corticosteroid-induced osteoporosis should therefore be instituted as soon after the commencement of glucocorticoid therapy as possible.