Biomedical subjects

C S de Vries

Publications and source records attributed to C S de Vries.

At least 19 recordsLinked to original sources

PubMed2007

Systemic lupus erythematosus prevalence in the UK: methodological issues when using the General Practice Research Database to estimate frequency of chronic relapsing-remitting disease.

PURPOSE: The purpose of this study was to calculate the prevalence of systemic lupus erythematosus (SLE) between 1992 and 1998 using the General Practice Research Database (GPRD) METHODS: We identified all individuals who had contributed at least 3 years of data to the GPRD and who had a diagnosis of SLE with supporting evidence of their diagnosis. We calculated the annual age- and sex-specific prevalence of SLE. Additionally, we stratified the prevalence by years of data contributed to the GRPD. RESULTS: In males the point estimate of the prevalence of SLE increased from 7.5/100,000 (CI(95) 6.3, 8.8) to 10.1/100,000 (CI(95) 7.8, 12.2) but this rise was not statistically significant. However, prevalence appeared to increase significantly amongst females from 42.6/100,000 (CI(95) 39.6, 45.6) in 1992 to 70.8/100,000 (CI(95) 65.1, 76.6) in 1998. This increase was mainly amongst women aged 50-79 and in those contributing more than 5 years of data and could not be explained by increasing incidence of SLE or decreasing mortality during the study period. CONCLUSIONS: We found an increasing prevalence of SLE that could not be explained by increasing incidence or decreasing mortality. This is almost certainly an artefact caused by the increased likelihood of detecting or confirming cases of chronic relapsing-remitting diseases with increasing time contributed to the GPRD.

Adolescent↗

PubMed2005

Myocardial infarction risk and hormone replacement: differences between products.

OBJECTIVES: To establish the risk of myocardial infarction (MI) in users of hormone replacement therapy (HRT) compared with non-users and to compare the risk between different HRT regimens. METHODS: A population-based cohort and case-control study, and a case-control study nested within a cohort of HRT users, using the UK General Practice Research Database. Differences between HRT regimen, mode of administration and duration and recency of use were examined whilst adjusting for confounding. RESULTS: In the cohort and case-control study, 4537 cases of MI were identified in 2.62 million observed women years, cases were age-matched to 27,220 controls. In both studies, current and past HRT use were associated with reduced risk estimates for MI compared with no prior use. MIs were less likely to be fatal amongst women who had used HRT than amongst never users (OR(adj) 0.58; 95% CI 0.45-0.75). No difference in risk was seen between current and past use, oral and transdermal HRT or between different regimens (p>0.44). In the nested study, no difference was found in the association with MI risk between different oestrogen-progestogen combinations or between different combinations and tibolone. Unopposed oestrogen use was not associated with a decrease in risk compared with combined HRT. CONCLUSIONS: These results are consistent with previous observational studies in supporting the hypothesis that use of postmenopausal HRT is associated with a decrease in risk of acute myocardial infarction (AMI). Case fatality differed between HRT users and non-users, suggesting a protective effect of HRT. This study does not demonstrate a difference between regimens.

Adult↗

PubMed2004

Venous thromboembolism associated with cyproterone acetate in combination with ethinyloestradiol (Dianette): observational studies using the UK General Practice Research Database.

PURPOSE: To derive risk estimates for venous thromboembolism (VTE) in women prescribed cyproterone acetate combined with ethinyloestradiol (CPA/EE), a drug licensed in the UK for the treatment of women with acne or hirsutism. CPA/EE provides a treatment option for women with polycystic ovary syndrome (PCOS). CPA/EE has been associated with an increased risk of VTE. METHODS: Using the General Practice Research Database, we conducted cohort and case-control analyses in all women aged 15-39 and then nested in a population of women of the same age with acne, hirsutism or PCOS. RESULTS: The incidence rate ratio (IRR) for VTE in women exposed to CPA/EE versus conventional combined oral contraceptives (COCs) was significantly raised (all women: 1.92; 95% CI: 1.22,2.88; nested: 2.51; 95% CI: 1.07,5.75). Using exposure to conventional COCs as the reference, the adjusted odds ratio (ORadj) for VTE associated with CPA/EE was 1.45 (95% CI: 0.80,2.64) in all women and 1.71 (95% CI: 0.31,9.49) in women with acne, hirsutism or PCOS. CONCLUSIONS: The risk of VTE associated with CPA/EE use does not differ significantly from that associated with the use of conventional COCs. These data are reassuring and together with knowledge of the risks associated with other treatments for acne, in particular, should influence prescribing practice.

Acne Vulgaris↗

PubMed2004

Utilisation of hormone replacement therapy in the United Kingdom. A descriptive study using the general practice research database.

OBJECTIVE: To determine prevalence and patterns of hormone replacement therapy (HRT) utilisation in women in the UK. DESIGN: Prospective observational study. SETTING: UK general practice. POPULATION: Women from general practices throughout the UK. METHODS: The study period was 1 January 1992 to 31 December 1998. Age-specific prevalence was calculated for each year. Trends in prescribing patterns were described over time. A sub-cohort of 'new starters' on HRT was identified to establish patterns of use, including duration of use and switching of preparations. Characteristics of the sub-cohort were compared with a reference group of non-HRT users. MAIN OUTCOME MEASURES: Prevalence, prescribing patterns and differences in characteristics between HRT users and non-HRT users. RESULTS: Among women aged 45-64, prevalence of HRT use increased from 18.6% in 1992 to 27.7% in 1998. Secular trends were observed away from prescribing combined-sequential preparations and towards use of combined-continuous preparations. Among the prescriptions for combined HRT products, only 4.3% contained medroxyprogesterone acetate (MPA). A total of 45.7% of women without a record of a hysterectomy and 53.8% of women with a record of a hysterectomy used HRT for at least three years. When women were partitioned by year of starting HRT, there was a trend of increasing duration of use across the seven years. Some women without a record of a hysterectomy were receiving unopposed oestrogen without progestogen supplementation. CONCLUSIONS: Within the past decade, use of HRT has increased among women in the UK with large numbers of women using HRT for long periods and treatment often tailored to the individual.

Cohort Studies↗

PubMed2004

A drug utilisation study of antidepressants in children and adolescents using the General Practice Research Database.

AIMS: To characterise prescribing patterns of antidepressants (ATDs) to children and adolescents aged < or =18 years in the UK. METHODS: Subjects issued at least one ATD prescription between 1 January 1992 and 31 December 2001 were identified from the UK General Practice Research Database. Prescribing patterns, annual prevalence, morbidity patterns, and time to discontinuation of ATD use were identified. RESULTS: A total of 24,976 subjects received 93,091 prescriptions; 51,868 (55.7%), 38,429 (41.3%), and 2708 (2.9%) prescriptions were for tricyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs), and other ATDs respectively. ATD prevalence increased 1.7-fold from 1992 to 2001. TCA prevalence decreased by 30% from 3.6 to 2.5 per 1,000; SSRI prevalence increased 10 times from 0.5 to 4.6 per 1,000. In new ATD users aged < or =10 years, the most common diagnosis associated with TCA use was nocturnal enuresis (75.1%); in those aged > or =15 years, it was depression (45.8%). Depression was also associated with SSRI use (69.0%). For new users with depression, the median treatment durations for TCAs and SSRIs were 30 and 58 days respectively. TCA users were more likely to terminate treatment than SSRI users (TCAs v fluoxetine: 1.40, 95% CI 1.32 to 1.47; non-fluoxetine SSRIs v fluoxetine: 1.01, 95% CI 0.96 to 1.07). CONCLUSIONS: SSRIs have gained popularity for the treatment of depression compared with TCAs. TCAs are still used despite their lack of efficacy in prepubertal depression and their moderate effect in adolescents. However, >50% of subjects discontinue treatment after two months, with TCA users stopping earlier than SSRI users.

Adolescent↗

PubMed2003

Differences in the use of combined oral contraceptives amongst women with and without acne.

BACKGROUND: Cyproterone acetate combined with ethinyl estradiol (CPA/EE) provides a treatment option for women with acne, hirsutism or polycystic ovary syndrome (PCOS). CPA/EE may be prescribed as an oral contraceptive (OC), but is not licensed as such in the UK. The use of CPA/EE steadily increased after its introduction to the UK market in 1987, but there was a marked increase in its share of the OC market after 1995. METHODS: Using the General Practice Research Database, utilization patterns of CPA/EE and conventional oral contraceptives were compared in women aged 15-39 years, with or without acne or PCOS. RESULTS: Between 1994 and 1998, CPA/EE accounted for an increasing proportion of all OC use. The proportion of CPA/EE prescribed to women with acne declined between 1994 and 1998, whereas that prescribed to women with PCOS remained constant. The age-specific use of CPA/EE by women with acne or PCOS almost doubled. After 1995, there was a marked increase in the use of products containing levonorgestrel by women with acne or PCOS. CONCLUSIONS: A large proportion of CPA/EE is prescribed to women with acne and/or PCOS, although this proportion decreased between 1992 and 1998. This has important implications in CPA/EE risk assessment studies.

Acne Vulgaris↗

PubMed2003

The risk of venous thromboembolism in women prescribed cyproterone acetate in combination with ethinyl estradiol: a nested cohort analysis and case-control study.

BACKGROUND: Cyproterone acetate combined with ethinyl estradiol (CPA/EE) is licensed in the UK for the treatment of women with acne and hirsutism and is also a treatment option for polycystic ovary syndrome (PCOS). Previous studies have demonstrated an increased risk of venous thromboembolism (VTE) associated with CPA/EE compared with conventional combined oral contraceptives (COCs). We believe the results of those studies may have been affected by residual confounding. METHODS: Using the General Practice Research Database we conducted a cohort analysis and case-control study nested within a population of women aged between 15 and 39 years with acne, hirsutism or PCOS to estimate the risk of VTE associated with CPA/EE. RESULTS: The age-adjusted incidence rate ratio for CPA/EE versus conventional COCs was 2.20 [95% confidence interval (CI) 1.35-3.58]. Using as the reference group women who were not using oral contraception, had no recent pregnancy or menopausal symptoms, the case-control analysis gave an adjusted odds ratio (OR(adj)) of 7.44 (95% CI 3.67-15.08) for CPA/EE use compared with an OR(adj) of 2.58 (95% CI 1.60-4.18) for use of conventional COCs. CONCLUSIONS: We have demonstrated an increased risk of VTE associated with the use of CPA/EE in women with acne, hirsutism or PCOS although residual confounding by indication cannot be excluded.

Acne Vulgaris↗

PubMed2002

Concomitant prescribing of benzodiazepines during antidepressant therapy in the elderly.

A follow-up study was performed in two ambulatory cohorts aged > or =65 to investigate whether the prevalence and incidence of anxiolytic/hypnotic benzodiazepine drug prescribing is comparable between users of serotonin reuptake inhibitors (SSRIs) and users of tricyclic antidepressants (TCAs). The prevalence and incidence of benzodiazepines during antidepressant therapy was estimated among users of TCAs and SSRIs. Coprescribing of benzodiazepines occurred in 53% of the TCA users and 57% of the SSRI users (prevalence RR 1.1; CI(95) 0.9-1.2). The average duration of benzodiazepine drug use was >65 days per 100 days of antidepressant use. During SSRI therapy, significantly more people started benzodiazepine drug therapy than during TCA therapy (incidence rate ratio (RR) 1.7; CI(95) 1.2-2.4). Analyses repeated 5 years later yielded similar results (overall incidence RR(MH) 1.6; CI(95) 1.3-2.0). These data indicate that SSRI use is associated with a significantly higher chance of starting benzodiazepines compared with TCA use.

Aged↗

PubMed2002

Prescribing of gastroprotective drugs among elderly NSAID users in The Netherlands.

BACKGROUND: Use of non-steroidal anti-inflammatory drugs (NSAIDs) is associated with an increased risk of gastrointestinal toxicity, in particular when risk factors are present. METHODS: A study was performed to investigate concomitant prescribing of gastroprotective agents (H2-receptor antagonists, proton pump inhibitors, or misoprostol) in an ambulatory cohort of NSAID users aged 65 years and over. The prevalence of concomitant prescribing was studied, as well as the prophylactic prescribing of gastroprotective drugs. A stepwise logistic regression was performed to determine predictive variables of prophylactic and concomitant gastroprotective drug prescribing. RESULTS: Co-prescribing of gastroprotective drugs occurred in 1522 (23%) (of which 944 concerned prophylactic prescribing) of the NSAID users (n = 6557), with an average duration of 67 days per 100 days of NSAID use. Co-prescribing of gastroprotective drugs varied among individual NSAIDs. Concomitant use of oral corticosteroids (ORadj 2.4; Cl95 2.0-2.9), coumarins (ORadj 1.6; Cl95 1.3-2.0), and low dose aspirin (ORadj 1.6; Cl95 1.4-1.9) were significantly associated with both prophylactic and concomitant prescribing of gastroprotective agents during NSAID therapy. DISCUSSION: Despite current guidelines recommending gastroprotective drug prescribing among high risk groups, the rate of concomitant prescribing of gastroprotective agents in NSAID users aged 65 years and over is low. Feedback to prescribers should be given to improve prescribing practices in this high risk group.

Aged↗

PubMed2001

Effect of diuretics on fetal growth: A drug effect or confounding by indication? Pooled Danish and Scottish cohort data.

AIMS: The diabetogenic effect of diuretics, as well as the indication for prescribing them, may impact on fetal growth. We analysed whether the purchase of prescription drugs for diuretics during pregnancy was associated with measures of fetal growth. METHODS: During 1991-98 all women who purchased prescription drugs for diuretics during pregnancy were identified in the Northern Jutland Prescription Database (NJDP), Denmark, and in the Medicines Monitoring Unit's Database (MEMO), Scotland. Information on birth weight and gestational age was obtained from the Danish Birth Registry, the Danish Hospital Discharge Registry and the Scottish Tayside Neonatal Database. Information on diabetes, hypertension and prepregnancy weight were obtained by hospital record review in a sample of women in the Danish cohort. Women who did not purchase prescription diuretics during pregnancy were used as a reference group in both cohorts. RESULTS: Danish women who purchased prescription loop diuretics during pregnancy gave birth to infants with higher birth weights than women who did not use diuretics; mean difference 104.7 g (95% CI; 2.6, 206.9). However, the high prevalence of diabetes (10.3%) among Danish women who purchased prescription loop diuretics during pregnancy might explain this result. Both the Danish and the Scottish women who purchased prescription diuretics during their pregnancy were at increased risk of preterm delivery (< 37 completed weeks); ORs: 1.8 (CI; 1.2, 2.7)NJDP, 1.9 (CI; 0.9, 4.3)MEMO. The proportion of hypertension among women who purchased prescription thiazides was 15.8%, and the risk of having an infant with a birth weight (BW) < 2500 g was increased; ORs: 2.6 (CI; 1.4, 5.0)NJDP, 2.4 (CI; 0.8, 7.8)MEMO. CONCLUSIONS: Prescribing diuretics during pregnancy was associated with differences in birth weight and incidence of preterm delivery. Confounding by indication may explain the findings.

Benzothiadiazines↗

PubMed2000

Drug utilisation in Dutch nursing homes.

OBJECTIVE: To quantify and evaluate drug utilisation in a sample of Dutch nursing homes. METHODS: A retrospective analysis of computerised medication data of 2355 residents aged 65 years and over from six nursing homes in the Netherlands was performed. For each therapeutic drug group, the number of users was determined. The ten therapeutic groups used most frequently were investigated further. For these, patient characteristics, use of therapeutic subgroups, the average daily dosages and the chronicity of drug use were determined. Chronicity was expressed as the percentage of treatment days divided by the number of residents' days in the nursing home. RESULTS: During the study period, 89%, 77% and 56% of the study population used a drug from the anatomical therapeutic chemical (ATC) main group N (nervous system), A (alimentary tract and metabolism) and C (cardiovascular system), respectively. Eight of the ten therapeutic drug groups prescribed most frequently were used for more than 50% of the time. In particular, psycholeptic drugs, diuretics and laxatives were used chronically (83%, 81%, and 80% of the nursing home stay, respectively). Except for a few drug groups, such as laxatives and diuretics, the prescribed daily dosages were relatively low. Twenty-eight percent of the residents received loop diuretics; these were prescribed in relatively high dosages. CONCLUSION: Drug utilisation in the nursing homes was high and many drugs were used chronically. In view of the risk of possible adverse effects and drug-drug interactions, the prescribing and dosage of psycholeptic drugs, laxatives, loop diuretics and ulcer-healing drugs should be re-evaluated, carefully.

Aged↗

PubMed1999

Prescription data as a tool in pharmacotherapy audit (I). General considerations.

This article discusses how prescription data that are available from pharmacies can be used as a tool to support the improvement of prescribing behaviour. For the optimal use of prescription data in pharmacotherapeutic audit, the specific aim of the audit meeting must be clear. Next, appropriate measures (quality of drug choice, volume, cost) have to be selected for the presentation and discussion of prescribing. For several aims of audit meetings, suggestions for adequate measures are given. For each stage of behavioural change the article describes why and how prescription data can provide a useful contribution. Finally, recommendations are given regarding prerequisites for the optimal use of prescription data. Important factors are that the prescription data should sufficiently cover the physicians' patient population, information regarding the extent of repeat prescribing is needed, and the prescribing of drugs with multiple indications can cause difficulties with the interpretation of the graphs. With this information in mind, feedback on prescribing can be tailored to the audit groups' needs and targeted to the intervention that is pursued.

Attitude of Health Personnel↗

PubMed1999

Prescription data as a tool in pharmacotherapy audit (II). The development of an instrument.

In many countries, prescription data are used as an instrument to provide feedback on prescribing. This article describes the development and implementation of a computer program as a tool for pharmacotherapy audit meetings and it illustrates the possibilities of such a program. The program was developed to support the optimisation of prescribing in the various stages of behavioural change. It enables pharmacists to make sophisticated overviews of prescribing by physicians in their audit group and furthermore, pharmacists can conduct drug utilisation studies or pharmaco-epidemiological studies in their own patient population. Forty percent of Dutch pharmacies have purchased the computer program since its introduction; it was distributed together with a technical handbook and a course book, which elaborated on the types of graphs available and their interpretation. An educational course was developed regarding the optimal selection and interpretation of graphs. Examples of prescription data as a tool to support various aims of audit meetings are given. The program is acknowledged as a welcome contribution to pharmacotherapy audit and to the pharmacists' advisory role in pharmacotherapy.

Attitude of Health Personnel↗

PubMed1999

The quality of Dutch hospital drug formularies: evaluation of technical features and organisational information.

INTRODUCTION: Hospital drug formularies (HDFs) are widely used tools to help influence clinicians' prescribing behaviour. Besides the therapeutic quality of HDFs, the available information and the way in which this is presented are key factors in HDFs' success or failure to influence prescribing behaviour and enhance prescribing quality. This research evaluates the technical features and organisational information of Dutch HDFs. METHODS: Seventy-two (75%) of all Dutch HDFs were evaluated based on criteria retrieved from international literature and additional criteria drafted by occupational groups working with HDFs. Aspects that were studied were physical appearance and layout, practicability with respect to the available information and how easily this could be retrieved from the HDFs, information regarding drug choice policies such as seamless care, and the available type of therapeutic and pharmaceutical information. RESULTS: Thirty-three (46%) of the HDFs were less than 3 years old. Physical appearance of all HDFs was very well looked after. Two (3%) HDFs were disease-oriented rather than drug-oriented. Changes from pre-admission therapy were addressed in 30 (42%) of the HDFs, but other seamless care policies were addressed in less than 20% of the HDFs. Finally, less than 50% provided therapeutic information that clinicians indicated as important. DISCUSSION: Although Dutch HDFs are technically practicable with respect to user-convenience, practice-oriented features are capable of improvements. Furthermore, Dutch HDFs lack important clinical information for daily practice. To enhance seamless care across healthcare, generic prescribing and prescribing on admission from and discharge to any other sectors should be addressed more specifically.

Data Collection↗

PubMed1999

Changing prescribing in the light of tolerability concerns: how is this best achieved?

Despite our knowledge regarding the efficacy, tolerability and optimal use of drugs, suboptimal prescribing still occurs. In view of all the factors that influence prescribing, this is not surprising. The focus of drug tolerability has changed from 'choosing the best alternative' when a drug is prescribed, to a balanced decision incorporating various different treatments from separate healthcare providers. This article reviews strategies that may influence prescribing behaviour and discusses practical considerations for achieving optimal prescribing in view of tolerability concerns. The patient has a major influence on prescribing and, with the current diversification of healthcare, the patient now controls prescribing behaviour more than ever before. Communication between healthcare providers consequently assumes a vital role. If messages are to be coherent and transferable, it is increasingly important that healthcare workers communicate effectively with one another regarding patients, prescribing patterns, and drug tolerability issues.

Drug Prescriptions↗

PubMed1998

Oral contraceptive use before and after the latest pill scare in The Netherlands. Changes in oral contraceptive use and how users change.

In October 1995, a "pill scare" developed in Europe. In the Netherlands, the recommendations given were 1) to not alarm women without risk for deep vein thrombosis (DVT), and 2) to be reserved in prescribing third generation oral contraceptives (OC) for young women who were beginning OC use. To determine whether there is a change in the prescription of third generation OC after the latest pill scare, prescription data from 1/10/94 to 1/10/96, covering a population of +/- 120,000 persons, were studied with respect to OC use before and after the pill scare. Trend analyses revealed a significant decline in third generation compared with total OC prescribing only in the youngest age category (p = 0.0034). Further, switch behavior was studied. Switches from third to second generation OC were more prevalent after the pill scare than before (odds ratio = 2.63; 95% confidence interval 1.84-3.75) and switches from second to third generation OC were significantly less prevalent after the pill scare. This indicates that Dutch prescribers have reacted to the pill scare in the way that the government recommended.

Adolescent↗

PubMed1998

Constipation as an adverse effect of drug use in nursing home patients: an overestimated risk.

AIMS: To investigate whether results from case control and cross sectional studies which suggest an association between laxative use and other drug use could be confirmed in a cohort study of nursing home patients. METHODS: A prospective cohort study of 2355 nursing home patients aged 65 years and over was performed to estimate the incidence relative risk of constipation associated with drug use. The study was conducted with prescription sequence analysis of each resident's detailed pharmacy records and data on morbidity and mobility. RESULTS: Use of drugs, which according to the summaries of product characteristics (SPC) and the literature on adverse drug effects have moderately to strongly constipating properties, was associated with a relative risk of 1.59 (95% CI 1.24-2.04) for the occurrence of constipation during exposure time. Use of drugs with mildly to moderately constipating effects was not associated with laxative use (RR 1.13; 95% CI 0.93-1.38). Stratification on the level of age, gender, type of nursing (psychogeriatric or somatic), morbidity, number of medications taken and mobility showed no confounding effects of these variables on outcome measurements. These variables all acted as effect modifiers. Effect of age and number of medications taken on the relative risk was nonlinear. CONCLUSIONS: Although an association between drugs that exhibit moderately to strongly constipating effects and occurrence of constipation was found, the risk was not as high as seen in previous studies. The high prevalence of constipation in nursing home patients is only partly due to adverse drug effects.

Aged↗

PubMed1996

Auditing GPs' prescribing habits: cardiovascular prescribing frequently continues medication initiated by specialists.

OBJECTIVE: To determine to what extent general practitioners' (GPs) prescribing behaviour is a result of repeat prescribing of medication which has been initiated by specialists. METHOD: During a 4-week period, pharmacists identified GPs' prescriptions for a large group of cardiovascular drugs. Next, questionnaires were sent to the prescribing GPs to find out whether the prescriptions were in fact repeat prescriptions. If they were, the GPs were asked whether or not they had originally been prescribed by a specialist. SETTING: Six pharmacies in the northeastern part of the Netherlands. SUBJECTS: Fourty-four GPs, 39 of whom responded. RESULTS: Of 1648 questionnaires, 1342 (81%) were returned. Of drugs for cardiovascular therapy that the GPs prescribed, 66% had originally been prescribed by specialists. CONCLUSIONS: For many cardiovascular drugs, GPs' prescriptions predominantly originated from specialists' prescribing. For more reliable attribution of prescription data or prescribing behaviour to either specialists or to GPs, similar studies should be made for other drug groups. Since the extent of repeat prescribing is high, qualitative studies should be made of the appropriateness of chronic medication, initiated by specialists and continued in repeat prescribing by GPs.

Cardiology↗