Evaluation of the nitrite and leukocyte esterase activity tests for the diagnosis of acute symptomatic urinary tract infection in men.

For 422 male patients with symptoms indicative of a urinary tract infection, nitrite and leukocyte esterase activity dipstick test results were compared with results of culture of urine samples. The positive predictive value of a positive nitrite test result was 96%. Addition of results of the leukocyte esterase test did not improve the diagnostic accuracy of the nitrite test.

Antibiotic treatment and resistance of unselected uropathogens in the elderly.

A population-based study was conducted among women over the age of 70 years with complaints of uncomplicated urinary tract infections (UTIs). The positive predictive value of the nitrite test alone or in combination with the leukocyte esterase test ranged between 83% and 99%. The nitrofurantoin prescription rate decreased whereas fluoroquinolone and amoxicillin/clavulanic acid prescriptions increased with increasing age. The aetiology of infection was age-dependent. Escherichia coli was the most commonly isolated uropathogen, followed by Proteus mirabilis and Klebsiella pneumoniae. For these uropathogens, the lowest susceptibility percentages were found for amoxicillin, trimethoprim and co-trimoxazole. As trimethoprim susceptibility reached approximately 75%, it may be advisable not to use this as a first-choice agent in the treatment of uncomplicated UTIs in the elderly.

Erythromycin resistance in the commensal throat flora of patients visiting the general practitioner: a reservoir for resistance genes for potential pathogenic bacteria.

The prevalence and mechanism of erythromycin resistance in commensal throat streptococci was determined from October 2000 until December 2002 as part of an ongoing study of the NIVEL in general practice patients (N=678). Resistance prevalence for 1mg/L and 16 mg/L erythromycin was 57% and 20%, respectively. The percentage of total commensal flora resistant within each patient ranged from 1% to 100% (median, 1%). mefA was predominantly found among isolates on the 1mg/L plates, and ermB was found in 64% of the isolates on the 16 mg/L plates. Erythromycin resistance was transferred from a commensal isolate to Streptococcus pneumoniae with a frequency of 1 x 10(-9). Commensal streptococci of general practice patients in The Netherlands form a large reservoir of transferable erythromycin resistance (genes) for potential pathogenic microorganisms.

[The influenza season 2004/'05 in the Netherlands with the largest epidemic of the last 5 years caused by the virus variant A/California and the composition of the vaccine for the season 2005/'06]. / Het influenzaseizoen 2004/'05 in Nederland met de grootste epidemie van de laatste 5 jaar, door virusvariant A/California, en de vaccinsamenstelling voor het seizoen 2005/'06.

In the Netherlands, the influenza epidemic of the 2004/'05 season started late. The background value of 3 cases of an influenza-like illness per 10,000 inhabitants per week was exceeded from week 1 until week 14 of 2005. The magnitude of the epidemic was the largest of the last 5 years, namely 104 per 10,000 inhabitants. As usual, the epidemic was caused mainly by influenza-A viruses of subtype H3N2 and to a lesser degree by A/H1N1 and B viruses. The H3N2-virus isolates belonged to the newly emerged variant A/California/7/04, which deviated slightly from the vaccine strain used for the 2004/'05 season. The influenza-B and H1N1 viruses matched the corresponding vaccine viruses well. For the 2005/'06 season, the World Health Organization has recommended the following vaccine composition: A/California/7/04 (H3N2), A/New Caledonia/20/99 (HiNI), and B/Shanghai/361/02.

Is the incidence of diabetes increasing in all age-groups in The Netherlands? Results of the second study in the Dutch Sentinel Practice Network.

OBJECTIVE: To assess possible changes in the incidence of diabetes in all age-groups in The Netherlands during a 10-year period (1980-1983/1990-1992). RESEARCH DESIGN AND METHODS: Since 1970, a network of sentinel stations (the Dutch Sentinel Practice Network) consisting of approximately 1% of the Dutch population has been in operation to gain insight into the morbidity patterns of the Dutch population as recorded by general practitioners. One of the items recorded from 1990 to 1992 was the incidence of diabetes. The first study with a similar design that registered the incidence of diabetes was conducted from 1980 to 1983. RESULTS: The overall incidence of diabetes increased significantly by 12.1% in the period between the two studies. This overall increase can largely be attributed to a statistically significant increase in the age-group 45-64 years (30.5%). Although not statistically significant, the 36% increase of diabetes in the age-group 0-19 years is in accordance with the increase of type I diabetes based on the first and second nationwide retrospective studies covering the total Dutch population. CONCLUSIONS: There is a marked increase in the incidence of diabetes in the age-group 45-64 years. This selective increase is probably not due to a real rise caused by changes in exposure to risk factors but to an earlier recognition of symptoms and signs of diabetes followed by blood glucose measurements and/or to more intensive case finding in general practice.

Impact of urbanization on detection rates of eating disorders.

OBJECTIVE: The purpose of this study was to examine the incidence of anorexia nervosa and bulimia nervosa among patients in primary care and to evaluate the impact of urbanization, age and sex differences, and changes over time. METHOD: During 1985-1989, 58 general practitioners, trained in diagnosing eating disorders, registered all of their patients who had diagnoses of anorexia nervosa and/or bulimia nervosa according to strict criteria. The study population (N = 151,781) was 1% of the population of the Netherlands; the distribution of sexes, ages, geographical locations, and degrees of urbanization in the study group was representative of the Dutch population. Main outcome measures were rates of newly detected cases and age-adjusted rate ratios. RESULTS: The crude annual incidence rate of detected cases in primary care per 100,000 person-years was 8.1 for anorexia nervosa and 11.5 for bulimia nervosa. The incidence of bulimia nervosa was lowest in rural areas, intermediate in urbanized areas, and highest in large cities (6.6, 19.9, and 37.9, respectively, per 100,000 females per year); no rural-urban differences for anorexia nervosa were found. Pronounced sex and age differences in incidence rates were observed. Over the 5-year period, there was no time trend in the incidence of anorexia nervosa, but the incidence of bulimia nervosa tended to increase. CONCLUSIONS: The incidence rates of eating disorders--as defined by detection rates in primary care--are higher than previously reported. Urbanization seems to be a risk factor for bulimia nervosa but not for anorexia nervosa.

Mammography requests in general practice during the introduction of nationwide breast cancer screening, 1988-1995.

Introducing an organised breast cancer screening programme for certain age groups in a population might induce opportunistic screening in adjacent (non-invited) age groups and influence health behaviour in the target population. We analysed the effect of the start of the Dutch national screening programme on the number of mammographies requested by 43-45 general practices for the age groups 30-39, 40-49, 50-69 and 70+ years, using logistic regression analysis. In all age groups an immediate increase was observed in the number of mammography requests after the start of the screening, which was largest and statistically significant in the target population of the screening programme (age 50-69 years). More than 2 years after the start of screening, the number of mammography requests in all age groups had decreased to the level before the start and in the age group 50-69 years the number of mammographies was significantly lower than before the screening started. The unexpected increase in mammographies after the start of the breast cancer screening programme might be related to registry problems or to the process of building up the screening programme. Eventually there was a decrease in the number of mammographies in the target population, probably an effect of the introduction of the national screening programme. Opportunistic screening was not clearly demonstrated in adjacent age groups.

Are influenza surveillance data useful for mapping presentations?

Geographical information system (GIS) based on mappings of influenza data are rare (http://www.b3e.jussieu.fr.80/sentiweb/fr) and influenza data are commonly aggregated for rather large areas (http://www.eiss.org, http://oms2b3e.jussieu.fr/FluNet). The most limiting factors for the use of morbidity-data from practices in GIS-based mappings are differences which are not related to morbidity. These differences may be due to consultation behaviour, interpretation of the case definition, age distribution of patients and other reasons. In order to reduce the impact of these non-morbidity related differences on the interpretation, the data of many practices are usually pooled and consequently rather large areas are presented. Extracting and harmonising the signals for increased morbidity from practices is a presupposition for mapping with a sufficient geographical resolution. The possibility to harmonise by reducing those confounding differences on a practice level is investigated. Different harmonisation methods were applied to data from Germany where acute respiratory infections (ARI) per consultations are registered and from The Netherlands were influenza like illnesses (ILI) per population are registered. The harmonisation of the indices between countries was achieved by scaling them in relation to the level of the index representative for the peak activity during a usual influenza epidemic. The Kriging method is applied as a means of spatial prediction for the influenza data. The preliminary results are discussed with respect to resulting mappings.

Unexplained severe chronic pain in general practice.

The aim of this study was to estimate the prevalence of unexplained severe chronic pain (USCP) in general practice and to report medical as well as psychological descriptions of patients suffering from this condition.A total of 45 GPs in 35 different practices included patients throughout the year 1996. Patients were included according to the following criteria: between 18 and 75 years of age; pain which had lasted at least 6 months; pain is the most prominent aspect in the clinical presentation; pain is serious enough to justify clinical attention; pain has led to obvious discomfort and disability in daily life for at least for 1 month. Medical aspects were measured with the IASP taxonomy while psychological aspects were derived from the MPI. The overall prevalence of USCP was 7.91 per 1000 enlisted patients. Estimates ranged between 1.87 in the youngest age group and 13.50 in the 55-59 age category. The lower back and lower limbs were most frequently affected and 31% of the patients had pain in more than three major body sites. Pain was most frequently associated by the musculoskeletal system and most often (nearly) continuous. Mean severity of current pain was 3.7 on a scale from 0 (indicating no pain) to 6 (indicating a lot of pain). Mean rating of 'average pain in the last week' was 4.1. Regarding the psychosocial and behavioural aspects of pain, 27% of the patients could be described as perceiving severe pain while gaining social support for it. Fourteen per cent felt in the category 'pain combined with affective and relational distress' and 10% was classified as 'coping well with pain intensities lower than those of the other groups'. The other half of the patients were on average or not classifiable on these aspects. Unexplained severe chronic pain lasting more than 6 months had on overall prevalence of 7.91 per 1000 enlisted patients, ranging from 1.87 in the youngest to 13.50 in the oldest patients in these 35 general practices in The Netherlands. Our prevalence estimate of USCP is low compared to other studies on chronic pain. Probably for three reasons: Firstly, our study was confined to unexplained pain and not all chronic pain. Secondly, our inclusion criteria focused the attention of very severe chronic pain patients, and thirdly, we have defined 'chronic' as more than 6 months, while others have been using shorter time spans.

Surveillance of respiratory pathogens and influenza-like illnesses in general practices - The Netherlands, winter 1997-98.

The Netherlands Institute of Primary Health Care (NIVEL) has coordinated the activities of a sentinel surveillance network of 43 general practices since 1970. These practices care for 1% of the Dutch population, a sample representative of the national pop

Diagnosis and antibiotic treatment of acute otitis media: report from International Primary Care Network.

STUDY OBJECTIVE: The relation between a history of disorders suggestive of acute otitis media, symptoms, and findings of an examination of the tympanic membrane and doctors' certainty of diagnosis. Also, to examine differences in prescribing habits for acute otitis media among doctors from different countries. DESIGN: Questionnaires were completed by participating doctors for a maximum of 15 consecutive patients presenting with presumed acute otitis media. SETTING: General practices in Australia, Belgium, Great Britain, Israel, The Netherlands, New Zealand, Canada, Switzerland, and the United States. PATIENTS: 3660 Children divided into the three age groups 0-12 months, 13-30 months, and greater than or equal to 31 months. MAIN OUTCOME MEASURES: General practitioners' responses to questions on their diagnostic certainty and resolution of patients' symptoms after two months. RESULTS: The diagnostic certainty in patients aged 0-12 months was 58.0%. This increased to 66.0% in those aged 13-30 months and 73.3% in those aged greater than or equal to 31 months. In all age groups diagnostic certainty was positively associated with the finding of a tympanic membrane that was discharging pus or bulging. Redness of the membrane and pain were also associated with certainty in patients aged 13-30 months, and a history of decreased hearing or recent upper respiratory infection was positively associated in patients aged greater than or equal to 31 months. The proportion of patients prescribed antibiotics varied greatly among the countries, from 31.2% in The Netherlands to 98.2% in both Australia and New Zealand, as did the duration of treatment. Patients who did not take antibiotics had a higher rate of recovery than those who did; the rate of recovery did not differ between different types of antibiotic. CONCLUSIONS: Doctors' certainty of diagnosis of acute otitis media was linked to patient's age. Improved criteria or techniques for diagnosing acute otitis media, especially in very young children, need to be developed. Antibiotic treatment did not improve the rate of recovery of patients in this study.

[The 2001/2002 influenza season and the vaccine composition for the 2002/2003 season]. / Het influenzaseizoen 2001/'02 en de vaccinsamenstelling voor het seizoen 2002/'03.

The epidemic in the influenza season 2001/2002 was of moderate activity just like in 2000/2001. The influenza epidemic started in week 2 of 2002 when the clinical influenza activity reported by the general practitioner network of the Netherlands Institute of Primary Health Care (NIVEL) increased. This was caused by influenza A viruses of the H3N2 subtype in particular. All influenza A viruses of this subtype were closely related to the vaccine strain for this subtype, A/Moscow/10/99. Influenza B viruses and influenza A/H1 viruses isolated this season had surprising features. The influenza B viruses originated from two lineages. Viruses of the B/Yamagata/16/88 lineage have been circulating for more than twelve years. The vaccine reference strain B/Sichuan/379/99 belongs to this lineage. The B/Victoria/2/87 lineage reappeared again after an absence in Europe of more than ten years and accounted for 50% of the influenza B viruses that were isolated in the Netherlands. Therefore the vaccine will have provided only partial protection against influenza B. The only influenza A/H1 virus that was isolated appeared to be of a new subtype H1N2. The H1 hemagglutinin of this virus was closely related to that of the vaccine strain A/New Caledonia/20/99. The N2 neuraminidase originated from recent human influenza A/H3N2 viruses. Therefore the vaccine probably provided good protection against the new H1N2 subtype. Based in part on these data, the World Health Organization has advised that the vaccines for the season 2002/2003 should contain the following or comparable influenza-virus strains: A/Moscow/10/99 (H3N2), A/New Caledonia/20/99 (H1N1) and B/Hong Kong/330/01, the latter being an influenza B virus of the B/Victoria/2/87 lineage.

[The 2002/2003 influenza season in the Netherlands and the vaccine composition for the 2003/2004 season]. / Het influenzaseizoen 2002/'03 in Nederland en de vaccinsamenstelling voor het seizoen 2003/'04.

As in the 2000/2001 and 2001/2002 seasons, the influenza epidemic in the 2002/2003 season started late (week 7 of 2003) and was only moderate in size. Influenza A (H3N2) and B viruses were detected in equal numbers among patients of general practitioners and these two viruses were therefore equally responsible for the epidemic. However, H3N2 viruses dominated isolates taken from hospitals. In haemagglutination-inhibition (HI) assays most of the H3N2 viruses proved highly reactive with antiserum to the vaccine-reference strain A/Moscow/10/99. This was also true for a number of isolates, including those obtained from nursing home residents, closely related to the reference strain A/Finland/170/03. However, an estimated 4% of the H3N2 isolates belonged to the variant A/Fujian/411/02 from China, which constituted the majority of the H3N2 viruses isolated in Europe in the later phase of the season. This variant reacted poorly with antiserum to A/Moscow/10/99. In H1 tests all influenza A(H1N1)-virus isolates and all B-virus isolates were closelyrelated to the corresponding vaccine-reference strains. Taking this data into consideration, the World Health Organization has advised the same vaccine composition for the 2003/2004 season as for the 2002/2003 season, namely: A/Moscow/10/99 (H3N2), A/New Caledonia/20/99 (H1N1) and B/Hong Kong/330/01. There is the possibility of a mismatch occurring between the H3N2-vaccine strain and the circulating H3N2 viruses in the coming influenza season. In March and April 2003 there was an outbreak of influenza-A (H7N7) fowl plague in the Netherlands. A special monitoring survey revealed that 91 people who had handled infected poultry became infected with the H7N7 virus. One of these later died as a result of this. None of the avian and human H7N7-virus isolates examined contained human or porcine influenza-A virus genes.

[The 2003/2004 influenza season in the Netherlands with a limited epidemic of the virus variant A/Fujian, and the vaccine composition for the 2004/2005 season]. / Het influenzaseizoen 2003/'04 in Nederland met een beperkte epidemie door de virusvariant A/Fujian, en de vaccinsamenstelling voor het seizoen 2004/'05.

In contrast to the three previous influenza seasons, the influenza epidemic of the 2003/2004 season started early in week 49 of 2003. The epidemic was predominantly caused by influenza-A viruses of the H3N2 subtype. All isolated influenza-A viruses were antigenically related to influenza virus A/Fujian/411/02, which was already detected in the influenza season 2002/2003 and that deviated from the vaccine-reference strain A/Moscow/10/99 to a certain extent. The magnitude of the epidemic was limited despite the fact that it was caused by influenza-A H3N2-virus-drift variants. Immunity caused by natural infection with influenza viruses during previous seasons or vaccination has possibly provided sufficient cross protection against these new H3N2-drift variant. No influenza-A viruses of the H1N1 or H1N2 subtypes were detected in the influenza season 2003/2004. Only a small number of influenza-B viruses were isolated, which all belonged to the B/Yamagata/16/88 lineage, which was temporarily replaced by the B/Victoria2/87 lineage in the previous influenza season. On the basis of epidemiological and serological data the World Health Organization has recommended the following vaccine composition for the 2004/2005 influenza season: A/Fujian/411/02 (H3N2), A/New Caledonia/20/99 (H1N1) and B/Shanghai/361/02.

[Influenza in the 1995/'96 season; vaccine composition for the 1996/'97 season]. / Influenza in het seizoen 1995/'96; vaccinsamenstelling voor het seizoen 1996/'97.

The 1995/'96 season in the Netherlands was marked by an influenza A/H3N2 epidemic that peaked in week 5I. In this week, 39 patients with influenza-like illness per 10,000 inhabitants contacted the sentinel physicians. With two exceptions, influenza A/H3N2 viruses exclusively were isolated during this epidemic period. In the first few months of 1996, a substantial number of influenza A/H1N1 and influenza B viruses were isolated as well. Serological characterization of the circulating viruses revealed that they all resembled the virus strains of the influenza vaccine of 1995/'96, which therefore probably will have provided good protection. Based on the epidemiological data from other countries and the fact that similar H3N2 viruses have been circulating since 1993, the World Health Organization has recommended to exchange the H3N2 component of the 1996/'97 vaccine for a Wuhan/353/95 (H3N2)-like strain.

[Influenza in the 1994/95 season; composition of vaccine for the 1995/96 season]. / Influenza in het seizoen 1994/'95; vaccinsamenstelling voor het seizoen 1995/'96.

The 1994/'95 season in the Netherlands was marked by a limited influenza activity which only emerged in late February. The influenza activity remained elevated until the end of April, which is unusually late, and epidemic activity was only reported in the south of the country. Both influenza A/H3N2 and B viruses were isolated in this period. In addition, influenza A/HINI viruses were isolated for the first time since March 1993, from two patients. The majority of the influenza A strains that circulated in the Netherlands in 1994/'95 reacted well with ferret antiserum raised against the strains of the 1994/'95 influenza vaccine, which therefore probably offered good protection. The reactivity of the B strains to antiserum raised against the vaccine strain, B/Panama/45/90, was only moderate, which implies that the protection against the Dutch influenza B strains was not optimal. Based on the results of the worldwide influenza surveillance, the World Health Organization (WHO) has recommended an alteration in both the A/H3N2 and the B component for the vaccine of 1995/1996.

[The influenza season 1997/'98 and the vaccine composition for 1998/'99]. / Het influenzaseizoen 1997/'98 en de vaccinsamenstelling voor 1998/'99.

The 1997/'98 influenza season in the Netherlands was marked by influenza A/H3N2 activity which never reached a true epidemic level. There was no real peak activity either but a prolonged period of increased activity of approximately eight weeks with a maximum in week 13, when sentinel physicians reported 16.6 cases of influenza-like illness per 10,000 inhabitants. It was not until week 18 of 1998 that the influenza activity declined to baseline levels. During the season, almost exclusively influenza A/H3N2 viruses were isolated, of which the majority resembled the new strain influenza A/Sydney/5/97 (H3N2). Further analysis of these variant viruses revealed that, although there was some cross-reactivity with the vaccine strain (A/Nanchang/933/95), no optimal protection could be expected to be induced by the vaccine. Antigenic characterisation of the sporadic influenza A/H1N1 and influenza B viruses showed that these were related to the vaccine strains. As a result of these findings, the World Health Organization (WHO) recommended to change the H3N2 strain in the influenza vaccine for the season 1998/'99 to an influenza A/Sydney/5/97(H3N2)-like strain. Based on epidemiological data from other countries, it was also decided to change the influenza A/H1N1 component to an influenza A/Beijing/262/95 (H1N1)-like strain.

[2000/01 influenza season and the vaccine composition for the season 2001/'02]. / Het influenzaseizoen 2000/'01 en de vaccinsamenstelling voor het seizoen 2001/'02.

In the 2000/01 season, the size of the influenza epidemic in the Netherlands was exceptionally small. Since the start of the Continuous Morbidity Registration of the Netherlands Institute of Primary Health Care (NIVEL) in 1970, the peak incidence of influenza-like illnesses has never been so low. The aetiology of the epidemic was also unusual. Most remarkable was the relatively extensive circulation of subtype H1N1 and the low activity of subtype H3N2. The epidemic started in week 1 of 2001 and ended in week 8. The antigenic properties of the influenza A (H1N1) viruses closely resembled those of the vaccine strain A/New Caledonia/20/99. This new variant of subtype H1N1 was first isolated in Asia in 1995 and was only (sporadically) detected in the Netherlands in the 1999/2000 season. Phylogenetic analysis showed that these viruses represent a new line of subtype H1N1. Following the influenza-activity caused by H1N1 viruses in the 2000/01 season, a small number of B and H3N2 viruses were also isolated up to week 19. Antigenically, these viruses were identical to those obtained in the previous years. On the basis of the antigenetic analyses presented, it can be concluded that the vaccine provided good protection against the circulating influenza viruses in the 2000/01 season. The World Health Organization recommends that influenza vaccines intended for use in the 2001/02 season of the northern hemisphere should contain the following, or antigenically similar, strains: A/Moscow/10/99 (H3N2), A/New Caledonia/20/99 (H1N1), and B/Sichuan/379/99.

[Influenza season 1999/2000 and vaccine composition for the season 2000/01]. / Het influenzaseizoen 1999/2000 en de vaccinsamenstelling voor het seizoen 2000/'01.

The first signs of influenza activity in the Netherlands during the 1999/2000 influenza season were the isolation of an influenza A (H3N2) virus in week 40 and of two more in week 43 of 1999. From week 50 onwards, a strong increase of the clinical influenza activity was observed which reached its peak in weeks 1 and 2 of 2000 and then rapidly declined. The clinical influenza activity was associated with the isolation of predominantly influenza A (H3N2) viruses. Near the end of the epidemic, influenza A (H1N1) and influenza B viruses were isolated sporadically. The antigenic properties of the influenza A (H3N2) viruses resembled those of the epidemic strains isolated in the previous season and the vaccine strain A/Sydney/5/97. This influenza season, influenza B viruses did not play a significant role and they matched the vaccine strain B/Yamanashi/166/98. In addition, a small number of influenza A (H1N1) viruses were isolated. Some of these viruses resembled the old variant of influenza A (H1N1) viruses, A/Bayern/7/95, whilst others showed a close antigenic relationship with the vaccine strain recommended for the next influenza season, A/New Caledonia/20/99. For the influenza season 2000/'01, it is recommended by the World Health Organization that the vaccines contain the following (or similar) virus strains: A/Moscow/10/99 (H3N2), A/New Caledonia/20/99 (H1N1) and B/Beijing/184/93.

[Influenza in the 1993/'94 season; composition of the vaccine for the 1994/'95 season]. / Influenza in het seizoen 1993/'94; vaccinsamenstelling voor het seizoen 1994/'95.

The influenza season 1993/'94 in the Netherlands and the rest of Northwestern Europe was marked by an influenza A/H3N2 epidemic. The morbidity of this epidemic was moderate, but a high mortality rate was observed. The epidemic viruses, represented by A/Netherlands/241/93 (H3N2), were characterised by haemagglutination inhibition assays and nucleotide sequence analysis. The viruses were related to A/Beijing/32/92 (H3N2), the vaccine strain for 1993/'94, but clear antigenic differences were detected. Therefore, the WHO has recommended a new A/H3N2 component, A/Shangdong/9/93, for the vaccine of 1994/'95. The onset of the epidemic was unusually early in the influenza season. An increase in the influenza activity was already noticed in the second week of November and it reached its peak in week 49. As a result of the early epidemic, the influenza vaccination programme had not been completed yet. Therefore, the point of time for vaccinating people at risk may have to be reconsidered and moved up in order to complete the vaccination programme earlier.