Filmpjes voor het afnemen van de Van Wiechenkenmerken door ouders: determinanten van gebruik

Inleiding: Korte filmpjes van de Van Wiechenkenmerken zijn ontwikkeld, zodat ouders deze kenmerken met hun kind kunnen uitvoeren. Door ouders meer te betrekken bij de ontwikkeling van hun kind en het ontwikkelingsonderzoek door de jeugdgezondheidszorg (JGZ) komen ze beter voorbereid op het consult en zijn ze tijdens het consult meer gelijkwaardige gesprekspartners. Het doel van dit onderzoek is om determinanten van huidig en toekomstig gebruik van de filmpjes (wel/niet aanbieden en ervaringen) door JGZ-professionals en gebruik (ervaringen) door ouders te onderzoeken om daarmee implementatie van de filmpjes binnen de JGZ te ondersteunen.

Methode: Er is kwalitatief onderzoek met semigestructureerde interviews uitgevoerd om de belemmerende en bevorderende determinanten van het gebruik van de filmpjes zoals ervaren door JGZ-professionals (n = 14) en ouders (n = 10) in kaart te brengen. Met data (n = 4.370 ouders) uit een online tool waarin de filmpjes en vragenlijsten werden getoond, is kwantitatief onderzoek uitgevoerd, waarbij de ervaringen van de ouders met de filmpjes en de uitkomsten op de leeftijdsspecifieke kenmerken van hun kind zijn afgenomen.

Resultaten: Het kwalitatieve onderzoek liet zien dat het gebruik van de filmpjes door de meeste JGZ-professionals en ouders als positief werd ervaren. Aandachtspunten waren onder andere het beperkte bereik en gebruik van de filmpjes bij specifieke groepen (bijvoorbeeld anderstaligen), gebrek aan tijd bij sommige ouders en JGZ-professionals, ouders misten feedback direct na afname van de Van Wiechenkenmerken en uitkomsten op kenmerken kwamen niet altijd overeen tussen ouders en JGZ-professionals. Het kwantitatieve onderzoek liet zien dat ouders de filmpjes gemiddeld een 8,2 als rapportcijfer gaven en dat ongeveer de helft van de ouders zich (meer) betrokken voelde bij de ontwikkeling van hun kind en (beter) waren voorbereid op de afspraak bij de JGZ. De kenmerken werden door 96–100% van de ouders begrepen. Bij enkele kenmerken moest er gebruik worden gemaakt van materiaal dat niet aanwezig was in elk huishouden, zoals een stoof of een driewieler.

Conclusie: JGZ-professionals en ouders waren positief over het gebruik van de filmpjes. Op basis van de determinanten uit dit onderzoek is een implementatieplan ontwikkeld om JGZ-organisaties te ondersteunen als zij het gebruik van de filmpjes willen implementeren.

Clinical and genetic characteristics of Dutch children with central congenital hypothyroidism, early detected by neonatal screening

OBJECTIVE

To evaluate clinical characteristics of patients with central congenital hypothyroidism (CH), detected in the Dutch neonatal screening program. This included patients with isolated central CH but the majority have multiple pituitary hormone deficiencies (MPHD).

DESIGN

Nationwide, cross-sectional study.

METHODS

Data was collected on clinical characteristics, endocrine tests and neuroimaging of central CH patients, detected by the Dutch neonatal screening and born between 1 January 1995 and 1 January 2015. Height and pubertal status were assessed during a study visit. Isolated central CH patients without a confirmed genetic diagnosis were offered genetic (re-)testing.

RESULTS

During the 20-year period 154 central CH patients were detected (incidence of permanent central CH 1:25 642). After excluding deceased (15), severe syndromic (7) and transient patients (6), 92 of 126 eligible patients were included (57 MPHD; 79% male). Sixty-one patients (50 MPHD) had been hospitalized before screening results were reported, but central CH was diagnosed on clinical grounds in only three of them (5%). MRI abnormalities consistent with pituitary stalk interruption syndrome were seen in 50 (93%) MPHD patients. Among isolated central CH patients, 27 (84%) had an IGSF1, TBL1X or IRS4 gene variant (53, 16 and 16%, respectively).

CONCLUSION

Many patients with central CH have neonatal health problems, especially MPHD patients. Despite hospital admission of two-thirds of patients, almost none were diagnosed clinically, but only after the notification of an abnormal screening result was received. This indicates that central CH, especially if isolated, is an easily missed clinical diagnosis.

Tracking of thinness and overweight in children of Dutch, Turkish, Moroccan and South Asian descent from 3 through 15 years of age: a historical cohort study

BACKGROUND

Overweight is shown to track (= to maintain a relative position in a distribution) from childhood to adulthood, but is mostly studied in preobesogenic cohorts and in single ethnic groups. Little is known about tracking of thinness by ethnicity.

OBJECTIVES

to determine (differences in) tracking of BMI (class) from 3 through 15 years and the prediction of BMI class at 13-15 years of age in contemporary Dutch, Turkish, Moroccan and South Asian children living in the Netherlands.

METHODS

Historical cohort of 7625 children, born 1994-1997, with 24,376 measurements of BMI. BMI z-score and BMI class was analysed using universal criteria. South Asian children were also assessed using ethnic specific BMI criteria. Diagnostic odds ratios (OR) and test properties were calculated to estimate the ability of BMI class at 3-4 years to predict BMI class at 13-15 years.

RESULTS

Tracking of thinness between 3 and 15 years was stronger than that of overweight, as indicated by a generally higher diagnostic OR. BMI trajectories between 3 and 15 years of age of thin, normal weight and overweight adolescents were, although significantly different, quite similarly shaped in children of Dutch, Turkish and Moroccan descent. The South Asian BMI trajectory deviated considerably from the other ethnic groups, but the differences disappeared when South Asian specific BMI criteria were applied. A substantial proportion of overweight developed between 5-10 years, after which less children shifted to other BMI classes. A total of 55-78% of children with overweight at 3-4 years retained their overweight at 13-15 years, and 10-20% of 3-4 year olds with thinness remained thin.

CONCLUSIONS

In all ethnic groups, overweight and especially thinness highly tracked into adolescence. South Asian children differed from the other ethnic groups when universal BMI criteria were applied, but with South Asian specific BMI criteria tracking patterns became more concordant.

Specific language impairment is associated with maternal and family factors

BACKGROUND

This study aimed to identify risk factors associated with specific language impairment (SLI).

METHODS

In a nested case-control design, 253 children attending special needs schools for severe speech and language difficulties in the Netherlands were matched for sex and date of birth with 253 children attending mainstream education. Data on perinatal, maternal and family issues were retrieved from well-child care files registered shortly after birth.

RESULTS

Children with SLI had younger mothers than children in the control group (mean 30 years 9 months vs. mean 31 years 9 months) (P = 0.02). Children with SLI were less frequently breastfed directly after birth (55% vs. 71%) (P = 0.0007) and were less frequently firstborns (33.3% vs. 46.2%) (P = 0.002). No statistically significant differences were found for any of the other risk factors.

CONCLUSIONS

A relationship was found between SLI and maternal age, being breastfed and place in the birth order. Perinatal risk factors do not seem to be strongly associated with SLI.

To screen or not to screen for adolescent idiopathic scoliosis? A review of the literature

OBJECTIVES

Over the years, there has been much debate about the desirability and efficacy of screening for adolescent idiopathic scoliosis. To analyse the current evidence from a public health point of view a renewed evaluation of the literature was performed.

STUDY DESIGN

Literature review.

METHODS

We performed two literature searches: from January 2000 to April 2015 for systematic reviews or guidelines on screening for adolescent idiopathic scoliosis and from January 2009 to April 2015 for all studies on adolescent idiopathic scoliosis and screening methods. We evaluated if screening for adolescent idiopathic scoliosis fulfils the criteria of the UK National Screenings Committee for appraising a screening programme.

RESULTS

Adolescent idiopathic scoliosis is a condition with an unpredictable natural history. The optimal age and frequency of screening are unknown; it is not possible to predict which patients will need (conservative or surgical) treatment. The Forward Bending Test has a positive predictive value of 2.6% and a sensitivity of 56% (95% CI 23-88%) for (conservative or surgical) treatment, and is therefore not valid enough for use in a screening programme. There seems to be sufficient evidence that brace treatment is effective for preventing progression of adolescent idiopathic scoliosis. It is not clear if screening is cost effective.

CONCLUSIONS

Despite evidence that brace treatment is effective for preventing progression of adolescent idiopathic scoliosis, the benefits from the screening programme do not outweigh the harms. From a Public Health point of view, there is not enough evidence to support a screening programme for adolescent idiopathic scoliosis.

Cost-effectiveness of newborn screening for cystic fibrosis determined with real-life data

BACKGROUND

Previous cost-effectiveness studies using data from the literature showed that newborn screening for cystic fibrosis (NBSCF) is a good economic option with positive health effects and longer survival.

METHODS

We used primary data to compare cost-effectiveness of four screening strategies for NBSCF, i.e. immunoreactive trypsinogen-testing followed by pancreatitis-associated protein-testing (IRT-PAP), IRT-DNA, IRT-DNA-sequencing, and IRT-PAP-DNA-sequencing, each compared to no-screening. A previously developed decision analysis model for NBSCF was fed with model parameters mainly based on a study evaluating two novel screening strategies among 145,499 newborns in The Netherlands.

RESULTS

The four screening strategies had cost-effectiveness ratios varying from €23,600 to €29,200 per life-year gained. IRT-PAP had the most favourable cost-effectiveness ratio. Additional life-years can be gained by IRT-DNA but against higher costs. When treatment costs reduce with 5% due to early diagnosis, screening will lead to financial savings.

CONCLUSION

NBSCF is as an economically justifiable public health initiative. Of the four strategies tested IRT-PAP is the most economic and this finding should be included in any decision making model, when considering implementation of newborn screening for CF.

Declining and stabilising trends in prevalence of overweight and obesity in Dutch, Turkish, Moroccan and South Asian children 3-16 years of age between 1999 and 2011 in the Netherlands

OBJECTIVE

In many developed countries, overweight and obesity prevalence seems to stabilise. The aim of this study was to determine trends between 1999 and 2011 in overweight and obesity prevalence, and mean Body Mass Index (BMI) z-score in Dutch, Turkish, Moroccan and Surinamese South Asian children in the Netherlands.

DESIGN

A cross-sectional population-based study with 136 080 measurements of height and weight of 73 290 children aged 3-16 years. BMI class and BMI z-score were determined with the latest International Obesity Taskforce (IOTF) criteria, with overweight defined as an adult BMI equivalent ≥ 25 and obesity ≥ 30. Time trends per year were analysed using logistic and linear regression analyses.

RESULTS

The prevalence of overweight in Dutch children declined from 13% to 11% (OR 0.960; 95% CI 0.954 to 0.965), but increased in Turkish children from 25% to 32% (OR 1.028; 95% CI 1.020 to 1.036). In Moroccan and Surinamese South Asian children, overweight rates were stable, but obesity prevalence decreased (OR 0.973; 95% CI 0.957 to 0.989, OR 0.964; 95% CI 0.943 to 0.985, respectively) as well as the mean BMI z-score (B=-0.010; 95% CI -0.014 to -0.006, B=-0.010; 95% CI -0.016 to -0.004). In Turkish children, trends limited to the period 2007-2011 showed no statistically significant relationship for all outcome measures.

CONCLUSIONS

The decrease in obesity prevalence in Dutch, Moroccan and Surinamese South Asian children suggests that overweight children became less adipose. The stabilising trend in overweight and obesity prevalence in Turkish children since 2007 may signify a levelling off for this ethnic group.

Ten-year quality assurance of the nationwide hearing screening programme in Dutch neonatal intensive care units

AIM

To evaluate 10-year quality assurance of newborn hearing screening (NHS) in Dutch neonatal intensive care units (NICU).

METHODS

Results of the two-stage automated auditory brainstem response (AABR) screening and diagnostic examination in NICU graduates were centrally registered between October 1998 and December 2008. This registration facilitates screening, tracking and follow-up after abnormal screening results. Outcome measures are referral rates, prevalence rate of hearing loss and (trends of) coverage rates and timeliness of follow-up.

RESULTS

Thirty-two thousand one hundred and two infants have been screened. Referral rates were 9.2% at the first and 26.3% at the second stage. Hearing loss was diagnosed in 728 infants (2.2%). Coverage rates were 98.7% at the first, 92.1% at the second stage, 92.3% for the diagnostic examination and 97.9% for the complete programme. After correction for gestational age, 95.8% of the infants had their first AABR<1 month, 81.8% of the referred infants had their second AABR<6 weeks and 67.1% were diagnosed<3 months. There was a positive trend in referred infants that had their second AABR<6 weeks (p=0.004) as well as in infants diagnosed<3 months (p<0.001).

CONCLUSION

The NHS in Dutch NICUs is effective. Timely identification of hearing loss is improving over time.

One-third of the new paediatric patients with sickle cell disease in The Netherlands are immigrants and do not benefit from neonatal screening

OBJECTIVES

To estimate the prevalence of children with sickle cell disease (SCD) in The Netherlands. To estimate the annual number of children newly diagnosed as having SCD and the proportion with diagnoses through neonatal screening To estimate the proportion of children with SCD receiving paediatric care in a comprehensive care setting.

DESIGN

Data from two sources, a survey of paediatric practices (n=107) and a laboratory database (n=20), were analysed by the capture-recapture method.

PARTICIPANTS

Children with SCD aged <18 years, either born before 2003 or newly diagnosed as having SCD between 2003 and 2007.

MAIN OUTCOME MEASURES

Prevalence, annual number of children newly diagnosed as having SCD, proportion of children with diagnoses through neonatal screening, proportion of children receiving paediatric care.

RESULTS

The prevalence of SCD in children living in The Netherlands on 1 January 2003 was 1:5152 (95% CI 1:4513 to 1:6015). In the next 4 years, the annual incidence was 1:2011 (95% CI 1:1743 to 1:2376). Nearly one-third (27%) of the children newly diagnosed as having SCD immigrated to The Netherlands after birth and would, therefore, be missed by the neonatal screening programme. Approximately 60% of all children with SCD were not reported by paediatricians.

CONCLUSION

The number of children with SCD in The Netherlands is much higher than previously estimated, and the majority of these children seem not to be reviewed regularly by a paediatrician. Children born abroad (27% of new cases) do not benefit from neonatal screening and are at high risk of life-threatening complications before SCD is diagnosed. As this introduces disparities in healthcare, the initiation of adequate measures should be considered.

Risk indicators for hearing loss in infants treated in different neonatal intensive care units

AIM

To assess which infants' characteristics and specialized procedures are risk indicators for unilateral or bilateral hearing loss (HL) and to evaluate whether these risk indicators are associated with variation in prevalence of HL between Neonatal Intensive Care Units (NICUs).

METHODS

For 2002-2005, data from the NICU hearing screening database in the Netherlands were matched with the national neonatology database in which all NICU infants with their patient characteristics and specialized procedures are registered. Multivariate logistic regression analyses were performed to assess risk indicators for HL and to explain differences in prevalence rates between NICUs.

RESULTS

A total of 10 830 infants were available for analyses. The prevalence of HL was 1.8% and ranged from 0.7 to 3.7% between NICUs. Infants' characteristics that significantly increased the risk of HL were the presence of craniofacial anomalies, chomosomal/syndromal anomalies, central nervous system conditions, circulatory system conditions and intra-uterine infections. The specialized procedures involving > or =12 days of intensive care and high frequency oxygenation ventilation were independent risk indicators for HL. Approximately 20% of the variance can be explained by the studied risk indicators. Differences in prevalence rates between NICUs were slightly reduced after adjustment for these risk indicators. NICUs with the highest prevalence rates of HL were situated in the largest cities in the Netherlands with a mixed population because of immigration. Therefore, ethnicity may be a risk indicator.

CONCLUSIONS

Several independent risk indicators for HL were found, but they could not explain all differences in prevalence rates of HL between NICUs.

Trends in overweight and obesity prevalence in Dutch, Turkish, Moroccan and Surinamese South Asian children in the Netherlands

OBJECTIVE

To determine trends in the prevalence of overweight and obesity in children in The Hague (the Netherlands) from 1999 through 2007.

DESIGN

Population-based study of a series of cross-sectional assessments of height and weight from electronic health records.

SETTING

Child Health Care (Municipal Health Service), The Hague.

PARTICIPANTS

50,961 children aged 3-16 years, with Dutch (59%), Turkish (17%), Moroccan (13%) or Surinamese South Asian (11%) ethnicity, representative of the four major ethnic groups in The Hague, with 85,234 weight and height measurements recorded in 1999-2007.

MAIN OUTCOME MEASURES

(Trends in) the prevalence of overweight (excluding obesity) and obesity as defined by the International Obesity Taskforce cut-off points, using logistic regression with year as independent variable.

RESULTS

From 1999 through 2007 there was a decrease in the prevalence of overweight in Dutch girls from 12.6% to 10.9% (OR 0.96; 95% CI 0.95 to 0.98) and an increase in Turkish boys from 14.6% to 21.4% (OR 1.08; 95% CI 1.04 to 1.11). Obesity prevalence rose significantly in Turkish boys from 7.9% to 13.1% (OR 1.04; 95% CI 1.01 to 1.06) and in Turkish girls from 8.0% to 10.7% (OR 1.04; 95% CI 1.01 to 1.08). Dutch boys, and Moroccan and Surinamese South Asian boys and girls showed no significant trends.

CONCLUSIONS

The declining prevalence of overweight in Dutch girls may indicate reversal of previous trends in the Netherlands. However, in Turkish children overweight prevalence and obesity is high and increasing. Further public health action is necessary, especially for Turkish children.

Phenylalanine tolerance can already reliably be assessed at the age of 2 years in patients with PKU

BACKGROUND

The clinical severity of phenylalanine hydroxylase deficiency is usually defined by either pre-treatment phenylalanine (Phe) concentration or Phe tolerance at 5 years of age. So far, little is known about the course of Phe tolerance or the ability of both pre-treatment Phe and Phe tolerance at early age to predict Phe tolerance at later age.

AIM

This study was conducted to investigate the course of the individual Phe tolerance and to assess the predictive value of both the pre-treatment Phe concentration and Phe tolerance at 1 and 6 months and 1, 2, 3 and 5 years for Phe tolerance at 10 years of age.

METHOD

Data on blood Phe concentration, prescribed Phe intake and weight of 213 early and continuously treated Dutch PKU patients up to 10 years of age were collected. Data acquired under good metabolic control were used in the study. Tolerance was expressed in mg/day and mg/kg per day.

RESULTS

Data at 1 and 6 months and at 1, 2, 3 and 5 years of 61, 58, 59, 57, 56 and 59 patients were included for comparison with the Phe tolerance at 10 years. Phe tolerances (mg/kg per day) at 2, 3 and 5 years showed a clear correlation with the tolerance at 10 years of age (r = 0.608, r = 0.725 and r = 0.661). Results for tolerance expressed as mg/day were comparable. Pre-treatment Phe concentrations did not correlate significantly with the tolerance.

CONCLUSION

Pre-treatment Phe is unreliable but Phe tolerance is a reliable predictor of the tolerance at 10 years of age, starting at 2 years of age.

Examination of long-lasting parental concern after false-positive results of neonatal hearing screening

OBJECTIVE

To investigate whether false-positive outcomes on neonatal hearing screening cause long-lasting parental concerns.

METHODS

A general population of parents whose children had participated in the universal neonatal hearing screening (UNHS) programme were examined. Parents filled out a questionnaire 6 months after UNHS. Outcomes were compared for all parents whose child tested positive or inconclusive in at least one of three tests but afterwards proved not to have hearing impairment (cases, n = 154) and a random sample of parents whose child passed the first test (controls, n = 288). Parental anxiety as measured with the State-Trait Anxiety Inventory (STAI), attitude towards the child (child health rating and experienced problems) and sensitivity to hearing problems were measured.

RESULTS

Median STAI score was equal for cases and controls. Parental attitudes toward the child also did not differ. The difference in the proportion of parents who worried about their child's hearing was statistically significant between cases and controls (p = 0.001) and varied with the number of screens; 4% of controls were worried about the child's hearing, as compared to 10% of cases whose children were tested twice, and 15% of cases whose children were tested three times.

CONCLUSIONS

False-positive UNHS test results do not cause long-term general parental anxiety. However, 6 months after screening, a considerable proportion of parents continued to experience hearing-specific worries regarding their child.

Developing evidence-based guidelines for referral for short stature

OBJECTIVE

To establish evidence-based guidelines for growth monitoring on a population basis.

STUDY DESIGN

Several auxological referral criteria were formulated and applied to longitudinal growth data from four different patient groups, as well as three samples from the general population.

RESULTS

Almost 30% of pathology can be detected by height standard deviation score (HSDS) below -3 or at least two observations of HSDS below -2.5 at a low false-positive rate (<1%) in 0-3-year-old infants. For 3-10-year olds, a rule concerning distance to target height of >2 SD in combination with HSDS <-2.0 has the best predictive value. In combination with a rule on severe short stature (<-2.5 SDS) and a minor contribution from a rule on "height deflection", 85.7% of children with Turner syndrome and 76.5% of children who are short because of various disorders are detected at a false-positive rate of 1.5-2%.

CONCLUSIONS

The proposed guidelines for growth monitoring show high sensitivity at an acceptably low false-positive rate in 3-10-year-old children. Distance to target height is the most important criterion. Below the age of 3 years, the sensitivity is considerably lower. The resulting algorithm appears to be suitable for industrialised countries, but requires further testing in other populations.

[Weight loss, serum sodium concentration and residual symptoms in patients with hypernatremic dehydration caused by insufficient breastfeeding]

OBJECTIVE

To determine the relationship between serum sodium concentration and weight loss as well as residual symptoms in newborns with hypernatremic dehydration caused by insufficient breastfeeding; and to determine the sensitivity of the following rule of thumb 'if weight loss is less than 10%, the baby does not have hypernatremic dehydration caused by insufficient breastfeeding'.

DESIGN

Systematic literature search.

METHOD

Medline was searched using the terms 'dehydration AND breastfeeding' for case reports on patients with 'hypernatremic dehydration caused by insufficient breastfeeding'. Reference lists from the articles retrieved were also searched. Articles published in 1970-2004 in Dutch, English, French, and German were included. All cases that the author diagnosed as 'hypernatremic dehydration caused by insufficient breastfeeding' were included.

RESULTS

A total of 47 articles were found, containing 128 relevant cases. Of these, 9 had less than 10% weight loss. Therefore, the sensitivity of the 10% rule was 93%. We found a linear relationship between the degree of weight loss and serum sodium concentration (Pearson's correlation coefficient = 0.71; p < 0.001). For every 10% increase in weight loss, the serum sodium concentration increased by 16 mmol/l (95% CI: 13-19). As the serum sodium concentration increased, the prevalence of residual symptoms increased. No residual symptoms were reported in patients with less than 10% weight loss.

CONCLUSION

A relatively strong linear relationship was found between weight loss and serum sodium concentration. If the weight loss was more than 10%, the serum sodium concentration was beyond the range of normal values. The rule of thumb had a high sensitivity; however, the specificity should be determined before the rule of thumb is implemented.

Growth monitoring and diagnostic work-up of short stature: an international inventorization

BACKGROUND/AIMS

Growth monitoring is almost universally performed, but few data are available on which referral criteria and diagnostic work-up are used worldwide for children with short stature.

METHODS

A short questionnaire, containing questions on auxological screening and on diagnostic criteria for short stature, was sent to all members of the European Society of Paediatric Endocrinology (ESPE) and to several pediatric endocrinologists outside Europe.

RESULTS

Responses were received from 36 countries. In 27 (75%) a child health care program existed and in 14 (39%) there was a protocol for referral of children with growth retardation. Height for age was mostly used as a referral criterion. Sixteen countries (45%) reported having a guideline in secondary health care for diagnostic work-up. Although all countries agreed on having biochemical, radiological and/or genetic tests in the diagnostic work-up, there was a wide variety of recommended tests.

CONCLUSIONS

There is little consensus on referral criteria and diagnostic work-up of children with short stature among industrialized countries. There is a need to establish evidence-based guidelines.

Cost-effectiveness of different treatment strategies with intrapartum antibiotic prophylaxis to prevent early-onset group B streptococcal disease

OBJECTIVE

To estimate the costs and effects of different treatment strategies with intrapartum antibiotic prophylaxis to prevent early-onset group B streptococcal (GBS) disease in the Netherlands. The treatment strategies include a risk-based strategy, a screening-based strategy, a combined screening/risk-based strategy and the current Dutch guideline.

DESIGN

Cost-effectiveness analysis based on decision model.

SETTING

Obstetric care system in the Netherlands.

POPULATION/SAMPLE

Hypothetical cohort of 200,000 neonates.

METHODS

A decision analysis model was used to compare the costs and effects of different treatment strategies with no treatment. Baseline estimates were derived from literature and a survey among parents of children affected by GBS disease. The analysis was performed from a societal perspective, and costs and effects were discounted at a percentage of 3%. Main outcome measures Cost per quality adjusted of life-year (QALY).

RESULT

The risk-based strategy will prevent 352 cases of early-onset GBS for 5.0 million Euros, indicating a cost-effectiveness ratio of 7600 Euros per QALY gained. The combined screening risk-based strategy has comparable results. The current Dutch guideline resulted in lower effects for higher costs. The screening-based strategy shows the highest reduction in cases of early-onset GBS, however, at a cost-effectiveness ratio of 59,300 Euros per QALY gained. Introducing the polymerase chain reaction (PCR) test may lead to a more favourable cost-effectiveness ratio.

CONCLUSION

In the Dutch system, the combined screening/risk-based strategy and the risk-based strategy have reasonable cost-effectiveness ratios. If it becomes feasible to add the PCR test, the cost-effectiveness of the combined screening/risk-based strategy may even be more favourable.

Behavioural factors related to metabolic control in patients with phenylketonuria

BACKGROUND

The objective of this study was to determine the importance of parental factors possibly related to dietary control in early and continuously treated patients with phenylketonuria (PKU).

METHODS

A questionnaire was disseminated among parents of 238 patients with PKU born after the nationwide introduction of newborn screening for PKU (1 September 1974) until 31 December 1995. The questionnaire was based on a behavioural model measuring people's attitudes, subjective norms, and self-efficacy. Dietary control was defined on the basis of mean phenylalanine (Phe) concentration of the PKU patients measured between 1 January 1994 and 31 December 1996.

RESULTS

Response rate was 71%. Attitudes: children of parents who believed that their child adheres well to the diet, even if his or her Phe concentrations are sometimes too high, had lower Phe concentrations than children of parents who disagree with this statement (adjusted difference -103 micromol/L, p < 0.001). Subjective norm: Phe concentrations were higher when parents answered that their relatives did not approve when their child deviates from the diet (p = 0.004). Self-efficacy: children of parents who reported difficulties in having their child eat the synthetic protein substitute three times a day had higher Phe concentrations than those of parents who did not have such difficulties (adjusted difference 156 micromol/L, p = 0.007).

CONCLUSION

More attention should be given to parents having their child eat the synthetic protein substitute at least three times a day and to teaching parents to keep strictly to the diet without being too rigid. These factors were strongly associated to dietary control and may be amenable to change.

Individual growth curve models for assessing evidence-based referral criteria in growth monitoring

The goal of this study is to assess whether a growth curve model approach will lead to a more precise detection of Turner sydnrome (TS) than conventional referral criteria for growth monitoring. The Jenss-Bayley growth curve model was used to describe the process of growth over time. A new screening rule is defined on the parameters of this growth curve model, parental height and gestational age. The rule is applied to longitudinal growth data of a group of children with TS (n=777) and a reference (n=487) group. The outcome measures are sensitivity, specificity and median referral age. Growth curve parameters for TS children were different from reference children and can therefore be used for screening. The Jenss-Bayley growth model, which uses all longitudinal measurements from birth to a maximum age of 5 years with at least one measurement after the age of 2, together with parental height and gestational age can achieve a sensitivity of 85.2 per cent with a specificity of 99.5 per cent and a median referral age of 4.2 (the last measurement between the age of 2 and 5 of each child is considered to be the moment of referral). Sensitivity increases by 2 percentage points when decreasing the specificity to 99 per cent. The Jenss-Bayley growth model from birth to a maximum age of 8 years with at least one measurement after the age of 2, together with parental height results in a sensitivity of 89.0 per cent with a specificity of 99.5 per cent and a median referral age of 6.1. For a specificity of 98 per cent, we obtain a sensitivity of 92.3 per cent. In comparison to conventional rules applied to the same data, sensitivity is about 11-30 percentage points higher at the same level of specificity for the Jenss-Bayley growth rule. We conclude that from the age of 4, growth curve models can improve the screening on TS to conventional screening rules.

The intake of total protein, natural protein and protein substitute and growth of height and head circumference in Dutch infants with phenylketonuria

In a previous study, Dutch children with phenylketonuria (PKU) were found to be slightly shorter than their healthy counterparts. In the literature, it has been hypothesized that a higher protein intake is necessary to optimize growth in PKU patients. The study aimed to investigate whether protein intake (total, natural and protein substitute) in this group might be an explanatory factor for the observed growth. Growth of height and head circumference and dietary data on protein intake (total, natural and protein substitute) from 174 Dutch PKU patients born between 1974 and 1996 were analysed retrospectively for the patients' first 3 years of life. Analyses were corrected for energy intake during the first year of life and for the clinical severity of the deficiency of phenylalanine hydroxylase by means of plasma phenylalanine concentration at birth. Neither protein nor energy intake correlated with height growth. A positive, statistically significant relation between head circumference growth and natural protein and total protein intake was found, but not with the intake of the protein substitute or energy. Therefore, this study suggests that improvement of the protein substitute rather than an increase of total protein intake may be important in optimizing head circumference growth in PKU patients.

[Increased risk of hepatitis B due to incomplete or untimely immunisation in one-quarter of infants of hepatitis-B-virus carriers]

OBJECTIVE

To determine the frequency of an increased risk of infection in children of hepatitis-B-virus carriers due to incomplete or untimely hepatitis-B immunisation.

DESIGN

Descriptive.

METHOD

Dates of birth and hepatitis-B immunisations were collected for all documented children of hepatitis-B-virus carriers in the vaccination registers, born in 2000 in The Netherlands. To assess the possible increased risk of infection, criteria were drawn up for the completeness and timeliness of the immunisations and on the basis of these the number of children who possibly had an increased risk of infection was determined.

RESULTS

In total, 731 of the 769 children (95%) had received hepatitis-B immunoglobulins and at least 3 vaccinations. For 200 children (26%) the deviation from the immunisation schedule was so great that the child was possibly (temporarily) inadequately protected.

CONCLUSION

A quarter of the children of hepatitis-B-virus carriers were immunised incompletely or at the wrong time. This calls for an adjustment of the immunisation schedule and national guidelines in which the responsibilities and tasks are clearly defined.

Towards evidence based referral criteria for growth monitoring

AIMS

To evaluate the performance of growth monitoring in detecting diseases. Turner's syndrome (TS) is taken as the target disease.

METHODS

Case-control simulation study. Three archetypal screening rules are applied to longitudinal growth data comparing a group with TS versus a reference group from birth to the age of 10 years. Main outcome measures were sensitivity, specificity, and median referral age.

RESULTS

Clear differences in performance of the rules were found. The best rule takes parental height into account. Combining rules could improve diagnostic accuracy.

CONCLUSION

Growth monitoring is useful to screen for TS. A combined rule that takes absolute height SDS, parental height, and deflection in height velocity into account is the best way to do this. Similar research is needed for other diseases, populations, and ages, and the results should be synthesised into evidence based referral criteria.

Many referrals under Dutch short stature guidelines

The number of referrals under strict adherence to the Dutch consensus guidelines for short stature was estimated using longitudinal data from 970 children (0-10 years). Results showed that over 38% of all children would have to be referred one or more times. There is therefore a clear need to revise the current guidelines.

Motor function under lower and higher controlled processing demands in early and continuously treated phenylketonuria

This study examined motor control in 61 early and continuously treated patients with phenylketonuria (PKU) and 69 control participants, aged 7 to 14 years. The pursuit task demanded concurrent planning and execution of unpredictable movements, whereas the tracking task required a highly automated circular movement that could be planned in advance. PKU patients showed significantly poorer motor control in both tasks compared with control participants. Deficits were particularly observed for younger patients (age < 11 years). Differences between control participants and PKU patients were significantly greater in the pursuit task compared with the tracking task, indicating more serious deficits when a higher level of controlled processing is required. Correlations with historical phenylalanine levels indicated a later maturation of the level of control required by the pursuit task compared with the tracking task.

[Youth health care: much prevention for little money]

As part of government policy, the 'Youth healthcare' prevention programme is offered free of charge to all children aged 0 to 19 years who are resident in the Netherlands. It consists of a programme of primary prevention (including vaccinations, information and advice) and secondary prevention (screening, surveillance, early diagnosis) and individual prevention and care. Many elements from the programme package have been shown to have a favourable cost-effectiveness relationship, in terms of health benefits and financially. Other elements have a social priority. The present government expenditure for the total youth healthcare package is about 380 million euros per year, that is 1900 euros per child. In terms of conditions prevented or years of life gained, this is cheaper than accepted prevention programmes for adults. The present approach can only be maintained and strengthened, if the expenditure is increased so that new programme elements can be investigated and--if found effective--implemented.

Sustained attention and inhibition of cognitive interference in treated phenylketonuria: associations with concurrent and lifetime phenylalanine concentrations

Fifty-seven 7-14-year-old early- and continuously treated phenylketonuria (PKU) patients and 65 matched controls performed a sustained attention task. PKU patients with plasma phenylalanine (phe) levels higher than 360 micromol/l at the time of testing exhibited, compared to controls, lower speed of information processing, a lower ability to inhibit task-induced cognitive interference, less consistent performance, and a stronger decrease of performance level over time. Patients with concurrent phe levels lower than 360 micromol/l did not differ from controls and were significantly better than patients with levels higher than 360 micromol/l. Strong relationships were found with task performance for phe levels during the pre-school years and between ages 5 and 7. These correlations were stronger than those between concurrent phe level and task performance. Significant multiple regression models were found with age accounting for the largest proportion of variance of tempo and tempo fluctuation, and lifetime phe levels (particularly phe level between ages 5 and 7) accounting for the largest proportion of variance of the relative number of inhibition errors and its increase over time. Phe level between ages 5 and 7 also contributed significantly to the variance of tempo and tempo fluctuation. Neuropsychological outcome was independent of IQ. The results indicate that strict dietary adherence during these periods is beneficial to attentional control later in life. We suggest that phe levels should be maintained under 360 micromol/l until approximately age 12, when development of attentional control approaches an adult level.

Newborn screening for congenital adrenal hyperplasia in the Netherlands

OBJECTIVE

To evaluate whether congenital adrenal hyperplasia (CAH) patients can be detected by newborn screening before the occurrence of life-threatening salt wasting and whether the prevalence, specificity, and sensitivity are adequate enough for a routine screening procedure.

DESIGN

From 1998, a 2-year regional pilot screening for CAH was performed. In 1998, cutoff levels for 17OHP were primarily based on birth weight, and in 1999 on gestational age. In addition, nationwide, all newly diagnosed patients with CAH were reported to the Dutch Pediatric Surveillance Unit to compare screened CAH patients with CAH patients in the area without screening.

RESULTS

In 2 years, 176 684 newborns were screened and 15 CAH patients (7 males/8 females) were detected. Therapy was started at the median age of 7 days. In the area without screening, 223 307 infants were born and 19 CAH patients (10 males/9 females) were reported to the Dutch Pediatric Surveillance Unit. Therapy was started at the median age of 14 days. The mean (standard deviation) serum sodium concentration was 134.5 (3.4) mmol/L in the area of screening versus 124.5 (10.8) mmol/L in the area without screening. The overall prevalence was 1:11 764. In 1998 and 1999, the specificity was 99.76% and 99.97%, respectively. The positive predictive value was 4.5% and 16%, respectively. To date, no false-negative cases have been detected.

CONCLUSION

Severe salt wasting can be prevented by neonatal screening. The prevalence, specificity, and sensitivity allowed addition of screening for CAH to the routinely performed national neonatal screening program.

Costs of different strategies for neonatal hearing screening: a modelling approach

OBJECTIVE

To compare the cost effectiveness of various strategies for neonatal hearing screening by estimating the cost per hearing impaired child detected.

DESIGN

Cost analyses with a simulation model, including a multivariate sensitivity analysis. Comparisons of the cost per child detected were made for: screening method (automated auditory brainstem response or otoacoustic emissions); number of stages in the screening process (two or three); target disorder (bilateral hearing loss or both unilateral and bilateral loss); location (at home or at a child health clinic).

SETTING

The Netherlands

TARGET POPULATION

All newborn infants not admitted to neonatal intensive care units.

MAIN OUTCOME MEASURE

Costs per child detected with a hearing loss of 40 dB or more in the better ear.

RESULTS

Costs of a three stage screening process in child health clinics are 39.0 pounds (95% confidence interval 20.0 to 57.0) per child detected with automated auditory brainstem response compared with 25.0 (14.4 to 35.6) pounds per child detected with otoacoustic emissions. A three stage screening process not only reduces the referral rates, but is also likely to cost less than a two stage process because of the lower cost of diagnostic facilities. The extra cost (over and above a screening programme detecting bilateral losses) of detecting one child with unilateral hearing loss is 1500-4000 pounds. With the currently available information, no preference can be expressed for a screening location.

CONCLUSIONS

Three stage screening with otoacoustic emissions is recommended. Whether screening at home is more cost effective than screening at a child health clinic needs further study.

Behaviour and school achievement in patients with early and continuously treated phenylketonuria

Thirty patients with early and continuously treated phenylketonuria (PKU) between 8 and 20 years of age were compared with 30 controls, matched individually for age, sex, and educational level of both parents, on behaviour rating scales for parents and teachers as well as a school achievement scale. PKU patients, as a group, demonstrated more problems in task-oriented behaviour and average academic performance than did matched controls. Interestingly, whereas male PKU patients were rated significantly lower on introversion by their teachers, female patients were rated significantly higher on introversion and lower on extraversion than matched controls. This sex difference was also reflected in the relationship between measures of dietary control and the behaviour clusters, suggesting that male and female patients respond differently to elevated Phe levels or the stress associated with PKU. The teacher rating on average academic performance of the PKU patients was associated with recent level of dietary control, which suggests that it might be improved by more strict adherence to the diet. In addition, academic performance correlated negatively with the behaviour cluster negative task orientation. Further studies are recommended to obtain a more complete evaluation of this relationship and to replicate the current findings on larger samples. Over the years a number of studies have examined behaviour and school achievement in patients with early treated phenylketonuria (PKU; McKusick 261600). In general, these studies have found that despite early treatment with a phenylalanine (Phe)-restricted diet, PKU patients demonstrate more behavioural and school problems than do healthy controls. The behaviour problems include both internalizing symptoms (e.g. solitary, unresponsive, anxious, depressed mood: Pietz et al 1997; Smith et al 1988; Weglage et al 1992) and externalizing symptoms (e.g. hyperactive, talkative, impulsive, restless: Hendrikx et al 1994; Kalverboer et al 1994; Realmuto et al 1986; Smith et al 1988), but not antisocial or socially negative symptoms (e.g. lying, teasing, disobedience: Kalverboer et al 1994; Pietz et al 1997; Smith et al 1988). With respect to school achievement, studies have shown that patients with early treated PKU more often repeat classes or need special tutoring (Berry et al 1979; Brunner et al 1983; Koch et al 1987; Rey et al 1996; Verkerk 1995), have to work harder than healthy controls to achieve the same results (Weglage et al 1993), or have specific deficits in arithmetic achievement scores (Azen et al 1991; Berry et al 1979; Fishler et al 1987; Koch et al 1987; Weglage et al 1993). Nevertheless, many questions regarding the behavioural and school problems of patients with early treated PKU remain unanswered. For instance, the relationship between behavioural and school problems on the one hand and levels of dietary control on the other is still relatively unclear. The few studies that examined this relationship, have focused primarily on children in primary school (Azen et al 1991; Koch et al 1987; Smith et al 1988). Furthermore, although several psychological studies have shown that the pattern of behavioural problems varies by sex (see Prior et al 1999a for a discussion), so far very few studies have examined this issue in PKU patients and results are contradictory (Kalverboer et al 1994; Pietz et al 1997; Smith et al 1988; Weglage et al 1992). In addition, so far no study has actually examined whether there is a relationship between the behavioural problems and school difficulties of PKU patients, even though this relationship has been well documented in the psychological literature (Prior et al 1999b; Richards et al 1995). The aim of the present study is therefore to examine these issues in patients with early and continuously treated PKU over a wide age range and in relation to dietary control. More specifically, school achievement as well as social and task-oriented behaviour (at home

Influence of timing and dose of thyroid hormone replacement on development in infants with congenital hypothyroidism

OBJECTIVES

To test whether early treatment with a high initial dose of levothyroxine can prevent suboptimal mental development in all neonates with congenital hypothyroidism (CH).

STUDY DESIGN

Sixty-one patients, 27 with severe CH and 34 with mild CH, were treated either early (<13 days) or late (> or =13 days) with either a high initial dose of levothyroxine (> or =9.5 microg/kg/d) or a low initial dose (<9.5 microg/kg/d). With these criteria, 4 treatment groups were formed. The results of the Bayley test, performed at the age of 10 to 30 months and expressed as mental developmental index (MDI) and psychomotor developmental index (PDI), were related to socioeconomic status, treatment group, initial free thyroxine (FT(4)) concentration, and mean FT(4) concentration during the first 3 months of treatment (FT(4)-A) and the ensuing 9 months (FT(4)-B).

RESULTS

Mean (+/- SD) MDI was 113 +/- 14, and mean PDI was 114 +/- 12. In the severe CH group, only the patients treated early with a high initial dose had normal MDI scores (124 +/- 16), whereas the scores of the other groups ranged from 97 to 103. In contrast, all patients in the mild CH group had normal scores (range, 122-125), except those in the group treated late with a low initial dose, whose score was 110 +/- 10. Forty-three percent of the variance in MDI and PDI scores was explained by treatment factors, such as the treatment group, initial FT(4) concentration, FT(4)-A, and FT(4)-B.

CONCLUSIONS

Our data suggest that optimal treatment includes achievement of euthyroidism before the third week of life by initiation of therapy before 13 days with a levothyroxine dose above 9.5 microg/kg/d and maintenance of FT(4) concentrations in the upper normal range during the first year. Thus treated, patients with CH can achieve normal psychomotor development at 10 to 30 months, irrespective of the severity of the disease.

Maternal smoking during lactation: relation to growth during the first year of life in a Dutch birth cohort

A recent article by Little et al. (Am J Epidemiol 1994;140:544-54) reported that infants in Seattle, Washington, who were breastfed by mothers who smoked gained more weight than either infants who were breastfed by mothers who did not smoke or infants who were bottle-fed by mothers who smoked. In this study, the authors aimed to verify this result with the use of data from the Social Medical Survey of Children Attending Child Health Clinics (SMOCC) cohort, a nationally representative cohort of 2,151 children born in the Netherlands in 1988-1989. During the first year of life, data on type of milk feeding, weight, length, and head circumference were collected at 1, 2, 3, 6, 9, and 12 months of age. Infants of smokers who were mainly breastfed in the first 3 months of life (n = 117) were compared with similarly breastfed infants of nonsmokers (n = 572), with infants of smokers who had been mainly bottle-fed (n = 270), and with infants of nonsmokers who had been mainly bottle-fed (n = 535). The authors failed to observe any additional increase in body mass, length, or head circumference in infants of breastfeeding smokers compared with infants of the three other groups. When the authors used all of their data to study growth with a multivariate longitudinal regression model (general estimating equations (GEE) model), the data showed clearly reduced growth in breastfed children (limited to the period after the second month of life) and some "catch-up" growth in body mass and head circumference in children with intrauterine exposure to tobacco.

Does impaired growth of PKU patients correlate with the strictness of dietary treatment? National Dutch PKU Steering Committee

To assess whether growth retardation in patients with phenylketonuria (PKU) is related to the strictness of their dietary treatment, the relationship between Z scores for height up to 3 y of age and different indices of dietary control in 103 early treated Dutch PKU patients was studied. As indices of dietary control, the mean phenylalanine (Phe) concentration, the frequency of plasma Phe concentrations < 200 and < 120 micromol/l, and the standard deviation of the individual plasma Phe concentrations were studied. These measures of the dietary control were divided into quartiles. The mean Z score of the studied patients showed a decrease of 0.18/y (SD 0.36). No statistically significant difference between any of the quartiles of the studied indices with growth retardation was found. None of the used indices of dietary control based on plasma Phe concentrations showed a relationship between different degrees of the strictness of dietary treatment with growth retardation in Dutch PKU patients.

Neuropsychologic development in early treated congenital hypothyroidism: analysis of literature data

The aim of this study was to determine the neuropsychologic development in patients with congenital (primary) hypothyroidism (CH) detected by screening and treated from early age. Seven studies were evaluated, including 675 CH patients and 570 controls. Criteria for inclusion of the studies were: 1) age of patients and controls > or = 5 y; 2) control group well defined in the original article. A meta-analysis of the data on the intellectual development was performed. All analyzed studies show a trend toward lower intelligence quotient (IQ) and--as far as investigated--poorer motor skills in CH patients compared with controls. Pooling of data showed a significant deficit of the mean IQ of 6.3 (95% confidence interval: 4.7-7.8). The most important independent risk factor for the eventual outcome appears to be the severity of CH (defined by initial thyroxine at the moment of diagnosis and by skeletal maturation); treatment variables do not seem to have an important effect the cognitive development. We conclude that CH, despite early detection and treatment, results in an IQ deficit; the severity of CH seems to be the most important individual risk factor. Our second conclusion is that, although biomedical risk factors are well investigated, the individual weight of these factors is yet largely unknown. This may be due to the variability of definitions and test tools, especially for the investigation of motor skills, that have been used.

The relation between neonatal thyroxine levels and neurodevelopmental outcome at age 5 and 9 years in a national cohort of very preterm and/or very low birth weight infants

Transient neonatal hypothyroxinemia is very common in preterm infants. The literature on the effect of this hypothyroxinemia is, however, controversial, and large or long-term follow-up studies are not available. In a nationwide prospective follow-up study on very preterm and (or) very low birth weight infants (n = 717), we studied the relationship between thyroxine levels in the 1st wk of life and neurodevelopmental outcome at 5 y of age and school performance at 9 y of age. Thyroxine concentrations from filter paper eluates were determined in 717 infants: 32% had levels of more than 3 SD below the mean (< 60 nmol/L). The percentage of infants with such low levels increased with decreasing gestational age. At the age of 5 y, 96% of survivors (n = 640) were available for extensive neurodevelopmental examination: 85 (13.3%) had a disability and 92 (14.3%) a handicap. At the age of 9 y, 83% of survivors (n = 552) answered a questionnaire on school performance: 300 (54.3%) were in mainstream education in a grade appropriate for age, 151 (27%) were in mainstream education with grade retention, and 101 (18.3%) were in special education. Both neurologic dysfunction at age 5 y and school failure at age 9 y were significantly related to lower neonatal thyroxine levels even after adjustment for other perinatal factors (odds ratio, 1.3). Whether this relationship is causal should be investigated. If a causal relationship exists, substitution therapy may at least partially prevent neurologic dysfunction and learning disabilities, both common sequelae of very preterm birth.

[20-year national screening for phenylketonuria in The Netherlands. National Guidance Commission PKU]

OBJECTIVE

Evaluation of the Dutch national screening programme for phenylketonuria (PKU).

DESIGN

Descriptive.

SETTING

Nationwide.

METHODS

Data on the screening were obtained from the laboratories, from the registration offices of vaccination and screening results and from the paediatricians to whom infants with positive screening values were referred, during the period from September 1st, 1974 to December 31st, 1993.

RESULTS

During the study period 3,481,738 infants were screened in the Netherlands (99.4% of all live births). The sensitivity of the programme was 98%, the specificity 99.99% and the positive predictive value 50%. The prevalence of PKU varied considerably between regions, e.g. from 1:33,600 in Zuid-Holland to 1:8,250 in Limburg (average in the Netherlands 1:18,000). The percentage of patients treated before the age of 22 days was 84% in the period from 1974 to 1988 and 95% in the period from 1989 to 1993 (p = 0.04). Birth weight in patients with PKU was 141 g (95% confidence interval: 66-216) less than the expected birth weight in the Netherlands. Furthermore, a slight growth retardation occurred in the first three years of life in early treated patients. The percentage of patients following special education was twice as high as in the general population (p < 0.001).

CONCLUSION

The screening procedure for PKU is functioning at a high level. Despite early treatment development of patients with PKU is slightly below normal.

Information processing in patients with early and continuously-treated phenylketonuria

A total of 33 patients with early and continuously-treated phenylketonuria (PKU) between 7 and 16 years of age and 33 matched controls participated in a study examining perceptual, central, and response-related mechanisms of information processing. The specific mechanisms studied were: perceptual filtering, memory search, response selection, response execution, and motor presetting. In addition, groups were compared on mean intelligence level and task oriented behaviour. The performance of the PKU patients practically matched that of the controls on all three tasks, suggesting that PKU patients who are continuously maintained on a well-controlled phenylalanine-restricted diet are not impaired in the elementary mechanisms of information processing. Furthermore, groups did not differ in mean IQ or task-oriented behaviour.

CONCLUSION

These results underline the importance of continued, well-controlled dietary treatment. Further studies are recommended to obtain a more complete evaluation of the potential of PKU patients under these stricter dietary treatment conditions.

[Frequency and determinants of episiotomy in second-line obstetrics in The Netherlands]

OBJECTIVE

To study factors that influence the probability of episiotomy in Dutch gynaecologist-supervised deliveries.

SETTING

Obstetric units of Dutch hospitals.

DESIGN

Observational study.

METHODS

Data of 65,313 gynaecologist-supervised, vaginal deliveries of live-born singletons registered in the Dutch National Obstetric Database of 1990, were used. Firstly, the effect of characteristics of the mother, the child, the pregnancy, and the delivery on the probability of episiotomy were assessed in univariate analyses. Subsequently logistic regression analysis was used to determine the effect of each variable, while adjusting for the other variables.

RESULTS

The episiotomy rate in the total group of gynaecologist supervised deliveries was 39%. In the subgroup of vaginal deliveries of live born singletons, the rate was 46%. Besides the well-known risk factors such as parity, instrumental delivery and length of second stage of labour, ethnicity was also found to have an independent effect on the risk of an episiotomy. Mediterranean, Creole and Hindu women had a lower episiotomy risk than Dutch women (OR: 0.47 and 95% CI: 0.44-0.51). Gynaecologists more often performed episiotomy than midwives, after adjusting for possible confounding factors (OR: 1.54; 1.46-1.63). In University hospitals fewer episiotomies were performed than in large non-university hospitals (OR: 0.81; 0.76-0.87.

CONCLUSION

The decision to perform episiotomy appears not to depend solely on factors related to perineal rupture or foetal complications. The probability of episiotomy is also influenced by attendant at delivery and type of hospital.

Differential misclassification of alcohol and cigarette consumption by pregnancy outcome

BACKGROUND

The validity of the results of studies using retrospectively collected information on exposures is often criticized, because cases may report differently from controls even if their true exposure status is the same. This study was performed to quantify the extent to which this effect (differential misclassification) may occur for alcohol and cigarette consumption by pregnancy outcome.

METHODS

Prospective as well as retrospective information on alcohol and cigarette consumption was collected for 2806 mothers resident in all 12 provinces of the Netherlands, who gave birth between 1978 and 1979. Changes in mean reported consumption and changes from user to non-user based on retrospective and prospective information were compared for cases and controls. This was done by calculating absolute differences (retrospective minus prospective) in reported consumption and by calculating 'misclassification odds ratios'. Further, conventional odds ratios based on retrospective information were compared with those based on prospective information. Outcome measures were stillbirth, small for gestational age (SGA), congenital malformations, preterm birth and low birthweight.

RESULTS

The only statistically significant result was found for smoking and SGA. Mothers with an SGA child retrospectively reported a higher number of cigarettes smoked than they had prospectively, more so than mothers of a control child. However, the odds ratios of the relation between SGA and smoking based on prospective and retrospective information, respectively, were virtually the same.

CONCLUSIONS

Our results suggest that information bias is unlikely to have a large influence on effect estimates in studies using retrospective information on alcohol and cigarette consumption.

Episiotomies and the occurrence of severe perineal lacerations

OBJECTIVE

To investigate the relation between the use of mediolateral episiotomy and the occurrence of severe (third degree) perineal tears in hospital deliveries in the Netherlands.

DESIGN

An observational study.

SUBJECTS

Data were derived from the Dutch National Obstetric Database (LVR) of 1990, from which 43,309 spontaneous, occipito-anterior, vaginal deliveries of live, singleton infants were investigated.

INTERVENTION

Medio-lateral episiotomy.

MAIN OUTCOME MEASURE

The occurrence of severe perineal tears.

RESULTS

The severe tear rate was 1.4% in the total study group. Using multiple logistic regression to control for possible confounding variables, the use of mediolateral episiotomy was found to be associated with a more than fourfold decrease in risk of severe lacerations (odds ratio 0.22, 95% CI 0.17 to 0.29). Further, in a logistic model deliveries in hospitals with restrictive use of episiotomy (< 11%) were compared with those in hospitals with liberal use of episiotomy (> 50%). Liberal use of episiotomy was not associated with a lower frequency of severe perineal tears.

CONCLUSION

Although a protective effect of mediolateral episiotomy on the occurrence of severe lacerations was found, liberal use of mediolateral episiotomy should be discouraged on the basis of our findings.

Predictors of mean phenylalanine levels during the first five years of life in patients with phenylketonuria who were treated early. Dutch National PKU Steering Committee

We studied the relationship between plasma phenylalanine level at first diagnostic visit, country of origin of the mother, birth cohort, child clinic, sex, and social class on the one hand and mean plasma phenylalanine levels in the first five years of life on the other hand in patients with phenylketonuria (PKU) who were treated early. The study population consisted of 131 early treated patients with PKU born during the period from September 1st, 1974 to December 31st, 1988 in The Netherlands. Plasma phenylalanine levels from first diagnostic visit (usually before the age of three weeks) up until the fifth birthday were registered. For each patient the mean phenylalanine level during that period was calculated. Our results suggest that 1) it is more difficult to maintain low phenylalanine levels in patients with a more severe form of PKU, 2) in recent years paediatricians have treated their patients with a stricter diet, 3) there are differences in perception between paediatricians of different clinics as to what levels are acceptable, and 4) treatment of patients from non-Dutch mothers is more difficult than treatment of patients with Dutch mothers.

Impaired prenatal and postnatal growth in Dutch patients with phenylketonuria. The National PKU Steering Committee

OBJECTIVE

To assess whether physical growth is affected in early treated Dutch patients with phenylketonuria (PKU).

METHODS

The birth weights of all 137 early detected patients with PKU born in the period from 1974 to 1988 in the Netherlands were compared with reference values. Height, head circumference, and weight were measured at the age at which treatment started (commonly about 2-3 weeks), at 6 months of age, and yearly from the child's first birthday up to the age of 10 years. These measurements were compared with reference values.

RESULTS

The adjusted birth weight in patients with PKU was 141 g (95% confidence interval (CI) 66 to 216 g) less than Dutch reference values by Kloosterman and 103 g (95% CI 9 to 196 g) less compared with the birth weight of another reference group. At the age at which treatment started, z scores of patients for height by age were -0.23 (95% CI -0.44 to -0.02) and z scores for head circumference by the age were -0.25 (95% CI -0.44 to -0.06). From the age at which treatment started up to the age of 3 years z scores for height by age further decreased to -0.74 (95% confidence interval -0.93 to -0.56), after which no additional decrease occurred. In contrast, z scores for head circumference increased from -0.25 at the first visit to 0.08 (95% CI -0.14 to 0.30) at the age of 1 year, after which they remained close to zero. Weight by height was close to the expected centiles for all ages.

CONCLUSION

Patients with PKU are growth retarded at birth and have smaller head circumferences than the normal population. In Dutch patients further growth retardation occurs in the first three years of life.

Social class, ethnicity and other risk factors for small for gestational age and preterm delivery in The Netherlands

Social class and ethnicity are important risk factors for small-for-gestational-age and preterm delivery in many countries. This study was performed to assess whether this is also the case in the Netherlands, a country with a high level of social security, relatively small income differences and easy access to medical care for all its inhabitants. Other risk factors that were taken into account were smoking, drinking, occupation, age and height. Information was collected by interview in the first 3 weeks of life of the mothers of 2027 (response 97%) live-born singletons born in the period from April 1988 to October 1989 in the study area. After adjustment for possible confounding factors very low social class, compared with high social class, was significantly associated with reduced birthweight (-4.0%; 95% CI, -7.4% to -0.7%), but not with preterm delivery (OR, 2.09; 95% CI, 0.67-6.48). The adjusted birthweight of Turkish infants (2.7%; 95% CI, -1.1% to 6.5%) and the adjusted birthweight of infants from Suriname or the Antilles (-1.6%; 95% CI, -5.5% to 2.1%) were not significantly different compared with infants of Dutch mothers. After adjustment, the frequency of preterm birth was lower in Turkish infants, but not significantly (OR, 0.22; 95% CI, 0.04-1.10), whereas the frequency of preterm birth in infants from Suriname or the Antilles was significantly higher (OR, 2.51; 95% CI, 1.04-6.08) compared with Dutch infants. Of the other factors the main risk factors were smoking (negatively related with birth-weight) and maternal age(ABSTRACT TRUNCATED AT 250 WORDS)

[Evaluation of a decade of neonatal screening for congenital hypothyroidism in The Netherlands]

OBJECTIVE

Evaluation of the Dutch screening programme for congenital hypothyroidism (CH).

DESIGN

Descriptive.

SETTING

Nationwide.

METHODS

Data on the screening were obtained from the administration body for vaccination and screening results, laboratories and paediatricians to whom infants with positive screening values were referred, during the period from January 1st, 1981 to December 31st, 1990.

RESULTS

Of all live births in the Netherlands, 99.5% (1,797,719) were screened for CH. During the study period, 10,165 children (0.57% of all screened infants) were referred. Of the referred children, 529 had primary CH and 53 had congenital thyrotropin deficiency syndrome (CTDS). The prevalences of primary CH and CTDS are 1:3,400 and 1:25,000, respectively. The sensitivity of the programme with respect to detection of primary CH and CTDS was 99% and 74%, respectively. For all forms of CH combined, the specificity of the programme was 99% and the positive predictive value 6%. The positive predictive value was especially low in the group of infants with low T4 and normal thyrotropin values. One of the goals of the programme is to realise the start of treatment in all patients before they reach the age of three weeks. Before the screening programme came into being, the cumulative proportion of patients treated on the 21st day was 6%. After the beginning of the programme, the proportion increased to 54%. In screened patients with a severe form of CH it is currently 72%.

CONCLUSION

The screening programme has made a substantial and important contribution to early and effective identification of patients with CH. A number of measures to decrease the number of false-positive results have been taken and others are at present being investigated. Although patients are now treated much earlier than before the programme started, substantial improvement in this respect is still possible. This can only be achieved by a collective effort of performers of the heel puncture, laboratories, administration body for vaccination and screening results, general practitioners and pediatricians.

Congenital hypothyroidism screening and the cutoff for thyrotropin measurement: recommendations from The Netherlands

OBJECTIVES

There is little agreement as to the optimal cutoff point for thyrotropin testing in primary thyroxine screening programs for congenital hypothyroidism. Most programs in the United States use a cutoff point of 10% of the lowest thyroxine values, whereas in the Netherlands a cutoff point of 20% is used. Therefore, the results of the Dutch program may provide valuable information about the optimal cutoff point.

METHODS

The frequency distribution of screening thyroxine values was studied in all cases of permanent primary congenital hypothyroidism (n = 481) detected in 1,601,603 screened children born during the period from January 1, 1981, to December 31, 1989, in the Netherlands.

RESULTS

Programs using a 10% cutoff point would have missed 1.5% of cases. Above the 10% cutoff point, the marginal costs increase quite rapidly because of the escalating numbers of thyrotropin measurements necessary to detect one case of permanent primary congenital hypothyroidism: 20,000 in the range of 11% to 15% and 40,000 in the range of 16% to 20%.

CONCLUSIONS

Based on these findings, a cutoff point of at least 10% is recommended.