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Biomedical subjects

H A Valkenburg

Publications and source records attributed to H A Valkenburg.

At least 19 recordsLinked to original sources
PubMed1992

Efficacy of antibiotic prophylaxis for prevention of native-valve endocarditis.

Whether antibiotic prophylaxis can prevent bacterial endocarditis is hotly debated. In an attempt to settle this issue, we have assessed the efficacy of prophylaxis for bacterial endocarditis on native valves in a nationwide, case-control study in the Netherlands. Cases were patients with known cardiac disease in whom endocarditis developed within 180 days of a medical or dental procedure for which prophylaxis was indicated. Of a total of 438 patients with endocarditis diagnosed during 2 years, 48 were eligible for the study. Controls were patients with the same cardiac status in whom endocarditis did not develop within 180 days of a similar procedure; of a total of 889 controls from five hospitals, 200 were eligible. Overall, about 1 in 6 patients in both groups had received prophylaxis. The best estimate of protective efficacy was 49% for first-ever endocarditis occurring within 30 days of a procedure. Endocarditis developed within 30 days of a procedure in only 13% of patients with a previously diagnosed heart lesion which predisposed to the disease. The findings suggest that strict adherence to generally accepted recommendations for prophylaxis might do little to decrease the total number of patients with endocarditis in the community.

Adolescent↗
PubMed1992

Epidemiology of bacterial endocarditis in The Netherlands. I. Patient characteristics.

BACKGROUND: Studies of the epidemiology of bacterial endocarditis are usually based on a retrospective review of medical records from referral centers serving diverse patient populations. These studies are therefore likely to suffer from selection bias. We conducted a nationwide prospective epidemiologic study of endocarditis in the Netherlands. METHODS: During a 2-year period, all cases of consecutively hospitalized patients with suspected endocarditis in the Netherlands were reported to us. While hospitalized, patients were visited for an in-person interview and a review of the medical record. RESULTS: Of 559 episodes, 438 met the criteria for endocarditis; these included 89 episodes of prosthetic valve endocarditis and 349 episodes of native valve endocarditis. Adjusted for age- and sex-specific population figures, the incidence was 19 per million person-years. The incidence increased significantly with age, and men were more often affected than women (266 and 172 cases, respectively). Rheumatic and congenital cardiac lesions formed most of the underlying heart diseases. Mitral valve prolapse was present in only 29 patients with native valve endocarditis (8.3%). A history of intravenous drug abuse was present in 32 patients (7.3%). Viridans streptococci, staphylococci, and enterococci together constituted 86% of the isolated bacterial strains. Only 1.1% of the patients had culture-negative endocarditis. Overall case fatality was 19.7% and varied widely according to causative microorganism. CONCLUSION: The distribution of causal microorganisms, the case fatality rate, and the incidence rate of endocarditis are age related. Therefore, a meaningful comparison of data is only possible between population-based cohorts of patients with endocarditis.

Age Factors↗
PubMed1992

Epidemiology of bacterial endocarditis in The Netherlands. II. Antecedent procedures and use of prophylaxis.

BACKGROUND: The reported frequency with which endocarditis is ascribed to an antecedent dental or medical procedure varies from 3% to 62%. METHODS: We performed a nationwide prospective study of the epidemiology of bacterial endocarditis in the Netherlands. During a 2-year period, all consecutively hospitalized patients suspected of having endocarditis were visited while still hospitalized for a review of the medical record and an in-person interview that focused on antecedent procedures and administered prophylaxis. All information was checked with pharmacists and dental and medical practitioners. RESULTS: Of 427 patients with late prosthetic or native valve endocarditis, 275 were eligible for antibiotic prophylaxis because of a previously known cardiac lesion (n = 197) or a prosthetic valve (n = 78). Of these 275 patients, 64 (23.3%) had undergone a procedure with an indication for prophylaxis within 180 days of onset; in 31 (11.3%) the procedures had been within 30 days of onset. Antibiotic prophylaxis had been administered to 17 (26.6%) of the 64 patients and to eight (25.8%) of the 31 patients. CONCLUSION: The results indicate that medical and dental procedures cause only a small fraction of endocarditis. The majority of patients develop the disease along other routes. For an incubation period of 180 days, full compliance with prophylaxis might have prevented endocarditis in 47 (17.1%) of 275 patients with late prosthetic or native valve endocarditis involving a previously known cardiac lesion who underwent a procedure with an indication for prophylaxis. For an incubation period of 30 days, prophylaxis might have prevented endocarditis in 23 (8.4%) of these 275 patients, or 5.3% of all patients with endocarditis (n = 427).

Anti-Bacterial Agents↗
PubMed1992

Prevalence of radiographic osteoarthritis in two elderly European populations.

Was compared the prevalence of radiographic osteoarthritis (ROA) in two elderly populations, one in Göteborg (Sweden) and one in Zoetermeer (The Netherlands). The comparison was preceded by an inter-observed analysis of 150 films, revealing lower percentage agreements and kappa values when analysing the films on a five-point scale compared to the analysis in a dichotomy of "abnormal" and "normal" films. An intra-observer analysis of 50 films revealed higher percentage agreement and kappa values of well over 0.75, suggesting that radiographs could be read by one observer when different populations are being compared. The prevalence of hand ROA was higher in the Göteborg population, while the prevalence of knee ROA showed no significant differences. No significant increase with age of the cohorts was found for hand ROA in either population and no increase with age for knee ROA was found in the Swedish population. In the Zoetermeer population, knee ROA increased with age in both sexes.

Age Factors↗
PubMed1992

Arthritis community education by leather puppet (wayang kulit) shadow play in rural Indonesia (Java).

As part of the WHO/International League Against Rheumatism (ILAR) sponsored community organized programme for the control of rheumatic disease (COPCORD), an arthritis community education programme (ACE) was undertaken utilizing the traditional form of entertainment in a rural area in Central Java-the wayang. The point prevalence rate of musculoskeletal complaints was estimated in 4683 men & women aged 15 years and over by house-to-house interviews. From 1105 respondents recording recent musculoskeletal pain, 844 were randomly selected and half the latter attended a puppet shadow play (wayang) incorporating the ACE. The other half, matched for age, sex and educational level who did not see the play, served as controls. A questionnaire containing biphasic choices of correct or incorrect ways of performing activities of daily living (ADL) to minimize musculoskeletal problems was administered to the whole group before, 1 month and 6 months after the wayang. Increased knowledge of correct ways of performing ADL (correct ADL) in the intervention group compared with the control group at 1 and 6 months after wayang was significant (P less than 0.05). Comprehension of correct ADL following the wayang could be demonstrated even in subjects who were illiterate and those who had attended primary school only. Retention of knowledge at the 6 month assessment declined more markedly in the illiterate group. ACE by wayang was shown to be feasible and effective in transferring knowledge on ADL to people with musculoskeletal problems in the sample population in Java. This effect could be shown even in the poorly educated section of the community.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

The menopause, urinary incontinence and other symptoms of the genito-urinary tract.

In a study on incontinence and other symptoms of the genito-urinary tract in postmenopausal women covering their prevalence, consequences and predisposing factors, the prevalence of incontinence was found to be 26.4%. Daily incontinence was present in postmenopausal women more than twice as often as before the menopause (P < 0.05). The frequency of medical consultation for such incontinence was low; only 26.1% of the postmenopausal women had ever seen their doctor about it. Urgency, nocturia and dyspareunia were more prevalent in postmenopausal women, while vaginal itching and discharge were more frequent in premenopausal women (P < 0.05). The prevalence of incontinence and the other genito-urinary symptoms was higher after surgical than after natural menopause. Multivariate analysis showed the menopause to be the only factor that contributed significantly to the onset of incontinence (P < 0.001).

Adult↗
PubMed1992

Awareness of need and actual use of prophylaxis: lack of patient compliance in the prevention of bacterial endocarditis.

Antibiotics are given before some medical and dental procedures to patients with congenital or acquired heart disease to prevent endocarditis. The majority of practitioners and patients are aware of the need for this prophylaxis, although in practice prophylaxis is administered infrequently. It is not known how often patients at risk for endocarditis undergo procedures which warrant the prophylactic administration of antibiotics, nor how often prophylaxis is actually administered to these patients. Two groups of adult patients and a group of children with a cardiac lesion predisposing to endocarditis were surveyed by either telephone interview or mailed questionnaire about awareness of the need for prophylaxis, procedures undergone within six months of the survey and the actual use of prophylaxis before these procedures. Of 455 patients surveyed, 371 (81.5%) responded, 258 (69.5%) of whom remembered receiving advice on prophylaxis. Recollection of advice ranged from 77% of those younger than sixty years to 48% of those aged sixty or older. The patients underwent 68 procedures for which prophylaxis was definitely indicated and 71 procedures with a possible indication for prophylaxis; 127 (91%) of these procedures were dental. Antibiotics were allegedly administered before the procedure to 31 patients (22%). There is marked discrepancy between recollection of the advice and actual use of prophylaxis. In view of this it is likely that patients often undergo procedures without antibiotic protection; however, only a few of these patients develop endocarditis.

Adolescent↗
PubMed1992

Molecular epidemiology of Haemophilus influenzae type b in the Gambia.

One hundred two invasive and 64 noninvasive isolates of Haemophilus influenzae were collected in the course of a 2-year prospective field study on the epidemiology of H. influenzae meningitis in The Gambia. The isolates were serotyped, biotyped, and subtyped by outer membrane protein (OMP) profile analysis (OMP subtyping). H. influenzae meningitis was found to be caused by serotype b (95%). In invasive disease, serotype a, although present in the throat of healthy children, caused only occasionally (5.9%) disease. The distribution of biotypes of H. influenzae appeared to be very similar to that found outside The Gambia. A distinct pattern of OMP subtypes, different from other parts of the world, is prevalent in H. influenzae type b (Hib) in The Gambia. OMP subtypes 2, 4, 5, 8, and 9 were observed to be predominant. These subtypes, except subtype 2, have not been described. L subtypes (subtypes 2, 4, and 8) were associated with invasive disease, whereas non-L subtypes (subtypes 5 and 9) were found more often in healthy carriers (P less than 0.001). A significant difference in geographical distribution was found in subtypes of noninvasive Hib strains (P less than 0.05). We conclude that in The Gambia H. influenzae invasive disease is caused mainly by type b strains with a limited number of OMP subtypes, which are different from the subtypes found elsewhere in the world. These data are important for the surveillance of Hib disease in developing countries and are baseline data for a Hib polyribosyl-ribitolphosphate-conjugated vaccine trial in The Gambia. Alternative Hib OMP vaccines should include a set of representative OMPs.

Bacterial Capsules↗
PubMed1992

Epidemiology of rheumatic diseases in rural and urban populations in Indonesia: a World Health Organisation International League Against Rheumatism COPCORD study, stage I, phase 2.

To determine the incidence of musculoskeletal pain, disabilities, and help seeking behaviour, a questionnaire was administered to a rural population of 2184 men and 2499 women and an urban population of 481 men and 590 women aged over 15 years by house to house interviews with completion rates of 95.2% (rural) and 97.1% (urban). The incidences of pain in the joints, back, or neck were 23.6% (rural) and 31.3% (urban). The incidence of disability due to an inability to walk, lift, carry, and dress was 2.8% (rural) and 0.9% (urban). The percentage of the population with pain who had to stop work owing to disability was 75% (rural) and 78% (urban). Official health care facilities were used by 62% (rural) and 71% (urban) of the population. Traditional health care was used by 87% (rural) and 89% (urban). The high percentage of subjects unable to work was due to a predominance of manual labour occupations (rural, 90%, urban, 80%). The age and sex specific incidence of rheumatic diseases in these populations were similar to other developing and developed countries. The primary rheumatology service was inadequate due to the low priority given by the health service to non-communicable diseases and inadequate rheumatology teaching of the primary health care doctors during undergraduate training. Musculoskeletal pain is a major public health problem in Indonesia and is still not fully appreciated.

Adolescent↗
PubMed1992

A 12 year follow up study in the general population on prognostic factors of cartilage loss in osteoarthritis of the knee.

The natural history and prognostic factors of cartilage loss in osteoarthritis of the knee were studied in subjects from a general population survey on rheumatic diseases in 1975-8. Baseline data were collected by questionnaire, physical examination, and weightbearing anteroposterior knee radiographs. Follow up of the subjects aged 46-68 years with radiological osteoarthritis grade 2-4 (Kellgren) took place in 1988-9. Cartilage loss was assessed by two observers who scored the change in joint space width between two radiographs. Thirty four per cent had cartilage loss. Prognostic factors and adjusted odds ratios (ORs) (95% confidence intervals) were: body mass index OR = 11.1 (3.3 to 37.3) fourth v first quartile; body weight OR = 7.9 (2.6 to 24.0) third v first tertile; age OR = 3.8 (1.1 to 13.4) > 60 v < or = 49 years; Heberden's nodes OR = 6.0 (1.5 to 23.1); clinical diagnosis of generalised osteoarthritis OR = 3.3 (1.3 to 8.3); and previous bow legs or knock knees OR = 5.1 (1.1 to 23.1). The relation of age with cartilage loss was also confounded by the presence of Heberden's nodes or a diagnosis of generalised osteoarthritis. There was no statistically significant relation for gender, meniscectomy, injury, uric acid concentration, chondrocalcinosis, smoking, and occupation related factors, except possibly standing.

Age Factors↗
PubMed1992

Natural menopause, oophorectomy, hysterectomy and the risk of osteoarthritis of the dip joints.

The purpose of this study was to determine whether postmenopausal women have an increased risk of developing radiological osteoarthritis (ROA), bony enlargement or Heberden's nodes of the distal interphalangeal (DIP) joints. Secondly, the effects of the duration of the postmenopausal period, age at menopause or duration of the fertile period on the occurrence of DIP-OA were studied. Data from a population survey were used and 143 postmenopausal women with a natural menopause, 53 with a hysterectomy and 75 with a hysterectomy and bilateral oophorectomy were compared with 374 premenopausal women. There was no significant association of these postmenopausal states with ROA, bony swelling or Heberden's nodes. Age adjusted odds ratios and 95% confidence intervals were 1.14 (0.68-1.91), 1.30 (0.72-2.35), 1.92 (0.77-4.76), respectively for the women with a natural menopause. After adjusting for age there was a positive relationship of Heberden's nodes with age at menopause and duration of the fertile period for women with a natural menopause.

Aging↗
PubMed1992

The epidemiology of gout and hyperuricemia in a rural population of Java.

The prevalence of gout and hyperuricemia was investigated by a survey of a total population of 4683 rural adults. The successful response rate was 95.2%. Of the respondents 85.3% of the individuals were examined. The prevalence of gout and hyperuricemia in men was 1.7 and 24.3%, respectively. The male to female ratio was 34:1 for gout and 2:1 for hyperuricemia. The observed higher prevalence of gout and hyperuricemia in this male Malayo-Polynesian population compared with Caucasian data, in spite of a lower life expectancy and subsistence economy, suggests that genetic and racial predisposition are key causative factors.

Adolescent↗
PubMed1991

Malignant lymphomas in children in The Netherlands in the period 1973-1985: incidence in relation to leukemia: a report from the Dutch Childhood Leukemia Study Group.

A retrospective study was done of the incidence of non-Hodgkin's lymphoma (NHL) in children in the Netherlands in the period 1973-85 in relation to that of acute lymphoblastic leukemia (ALL). Complete ascertainment of cases was most likely achieved through the network of cooperating pediatricians of the Dutch Childhood Leukemia Study Group (DCLSG). The incidence of NHL remained constant at 0.75 per 10(5) children per year; the boy/girl ratio was 2.5. In +/- 25% of cases the disease was localized at diagnosis. Of children with NHL who were not listed in the DCLSG leukemia register, 19% had greater than or equal to 25% lymphoblasts in the bone marrow at diagnosis, representing an overlap with ALL of +/- 5%. In 1% of the children with NHL an immuno-deficiency disorder preceded the diagnosis. The incidence of Hodgkin's disease (HD) was 0.3 per 10(5) children per year, with some fluctuation over time, the peak being 0.7 in 1983. The boy/girl ratio was 2.7. Age-specific incidence rates, clinical features of NHL and HD, as well as the ALL to NHL ratio corresponded with those in other European countries and for white children in the USA.

Adolescent↗
PubMed1991

Rheumatic disease in a Philippine village. II: a WHO-ILAR-APLAR COPCORD study, phases II and III.

Many difficulties were encountered in a population survey of rheumatic complaints in a remote village area in the Philippines affecting the reliability of estimates of population prevalence. In phase I, a simple questionnaire identified 269 adults out of 950 who had rheumatic symptoms. In Phase II, 234 or 87% of positive respondents were requestioned using a more detailed pro forma. There were 196 with peripheral joint pain, 67 with neck pain and 137 with back pain. One third attributed their symptoms to work and 127 subjects had to stop work because of their complaints. Disability, including an inability to carry loads, affected nearly 1.8% of the population. Questions designed to detect rheumatoid arthritis and gout were not satisfactorily answered. Of those with complaints, 82% indicated that they still required help for their symptoms. In phase III, 166 subjects were medically examined. Osteoarthritis of the knee was found in 25 and 17 had Heberden's nodes. There were 16 with epicondylitis; 16 had rotator cuff pain and 35 had levator scapulae insertion pain. Three of these and three others had neck or shoulder swellings related to carrying loads on poles. Definite rheumatoid arthritis was diagnosed in two subjects and gout in five. No case of ankylosing spondylitis was identified. Thus, rheumatic complaints were common in this rural community and were frequently severe enough to cause disability and loss of time from work. Health worker education is required on how to handle these problems.

Adolescent↗
PubMed1991

Distribution, antibiotic susceptibility and tolerance of bacterial isolates in culture-positive cases of endocarditis in The Netherlands.

During a two-year period data were collected nationwide in The Netherlands on 438 episodes of bacterial endocarditis (BE) in 432 patients. Of the strains isolated in these patients 419 were available for analysis. Of these, 326 were isolated in native valve endocarditis (NVE) and 93 in prosthetic valve endocarditis (PVE). Viridans streptococci, staphylococci and enterococci together constituted 87% of the isolates. More than 46% of the viridans streptococci consisted of Streptococcus sanguis. Enterococcus faecalis and Staphylococcus aureus were the predominant species in the late form of PVE. The majority of the viridans streptococci and haemolytic streptococci were highly susceptible to penicillin. Five of 35 strains of coagulase negative staphylococci were resistant to methicillin. Eleven percent of a random sample of the streptococci collected were tolerant to penicillin. After repeated exposure to a concentration gradient of an appropriate beta-lactam antibiotic, this figure increased to 49%. Of the staphylococci, 5-6% of the strains were tolerant before induction and 16-20% after induction. Of the Enterococcus strains (n = 40), 12.5% showed high-level resistance to one or more aminoglycoside.

Drug Resistance, Microbial↗
PubMed1991

A longitudinal study of back pain and radiological changes in the lumbar spines of middle aged women. I. Clinical findings.

The natural history of low back pain was evaluated over a nine year period in two groups of middle aged Dutch women selected from the general population. One group had recurrent back pain (n = 236) and the other group had never experienced back pain (n = 241). At the onset of the study recurrent back pain was associated with smoking, previous use of the 'pill', pain in other joints, frequent headaches, and restricted lumbar spine movement. Nine years later 170 (72%) of the group with back pain had continuing pain and 58 (24%) of the group without previous back pain had incident pain. Pain in other joints, especially the hip and knee, was a predictor of continuing and incident pain but age, body mass index, and smoking were not.

Back Pain↗
PubMed1991

A longitudinal study of back pain and radiological changes in the lumbar spines of middle aged women. II. Radiographic findings.

The natural history of radiological changes in the lumbar spine was evaluated in two groups of middle aged Dutch women selected from the general population. One group (n = 236) had recurrent back pain and the other (n = 241) had never experienced back pain. At the beginning of the study disc degeneration was more common in the group with back pain. Osteoporotic vertebral fractures were equally common in both groups. Nine years later both groups showed an increase in prevalence of disc degeneration and osteoporotic fractures. The strongest predictor for change in disc degeneration was the presence of degeneration at the beginning of the study. The development of disc degeneration for the first time was related to body mass index.

Back Pain↗