A population-based case-control teratologic study of oral erythromycin treatment during pregnancy

The objective of the study was to evaluate the human teratogenic potential of oral erythromycin treatment during pregnancy in the population-based dataset of the Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980-1996. Of 38,151 pregnant women who had newborn infants without any congenital abnormalities (population control group), 172 (0.5%) had received erythromycin, while of 22,865 pregnant women who had newborns or fetuses with congenital abnormalities, 113 (0.5%) had been treated with erythromycin (crude OR with 95% Cl = 1.1, 0.9-1.4). The case-control pair analysis did not indicate a teratogenic potential of erythromycin during the second through third months of gestation, i.e., in the critical period for most major congenital abnormalities. The frequency of maternal erythromycin treatments during the second-third months of pregnancy was also not higher in different congenital abnormality groups compared with the rate of the total control group as referent. Thus, treatment with oral erythromycin during pregnancy did not present detectable teratogenic risk to the fetus.

A one-year population-based study of drug prescriptions for Danish children

We examined the pattern of prescribed drug use in Danish children and used a pharmacoepidemiological prescription database to identify all reimbursed prescriptions for children aged 0-15 y living in North Jutland County (population 95 189), Denmark, during 1997. We identified 154 189 prescriptions for 48 091 drug users. The 20 most frequently prescribed chemical substance subgroups comprised 71.3% of all prescriptions. The mean annual prescription rate was 1621/1000 children/y. Overall, 50.6% of the population received one or more prescription. In children younger than 3 y, 75.3% received prescriptions and 17.5% obtained five or more prescriptions. Systemic antibiotics, anti-asthmatics, ophthalmologicals and dermatological corticosteroids accounted for 82% of prescriptions. One-third of the young children received anti-asthmatics, mainly oral beta-2 agonists, and almost half received antibiotics, mainly broad-spectrum penicillins. In the 7-15-y-olds, 39.1% received prescriptions. Hormones, antihistamines, anti-epileptics, anti-acne preparations and anti-diabetics comprised an increasing proportion of prescriptions. About 20% received antibiotics and 6% anti-asthmatics. In conclusion, the level of exposure to prescribed drugs was considerable at all ages and was highest in early childhood. Our study supports the need for epidemiological studies on the reasons for drug use and evaluation of their pharmacological effects in children.

Teratogenic evaluation of oxacillin

Teratogenic studies of oxacillin in humans have not been published. The population-based data-set of the Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980-1996 contains 22,865 foetuses or newborns with congenital abnormalities and 38,151 matched control newborns without congenital abnormalities. The mothers of 14 cases and 19 controls were treated with oral oxacillin during pregnancy. A teratogenic risk of oxacillin was not detected in this case-control study.

Long-term follow-up of cognitive outcome after breech presentation at birth

Studies of long-term consequences of birth in breech presentation are sparse. Therefore, we conducted a cohort study linking birth registry data with data collected during evaluation for military service in 4,298 conscripts born between 1973 and 1976. The cognitive functions were measured with the Boerge Prien IQ test. A total of 164 conscripts were born in breech presentation and 70 (42.7%) of these were delivered after Caesarean section. The mean Boerge Prien test score was 43.2 among men born in cephalic presentation and 39.9 among those born in breech presentation for a difference of 3.3 (95% confidence interval = 1.8-4.7). The negative association between breech presentation and cognitive outcome persisted after stratifying by Caesarean section and after adjustment for confounders. It also persisted when we restricted the analyses to term singleton pregnancies.

Prescribing during pregnancy and lactation with reference to the Swedish classification system. A population-based study among Danish women

AIM

To assess the current prescribing pattern for 15,756 primiparae before, during, and after their pregnancies with reference to fetal and neonatal risk.

METHOD

A prescription database study with linkage to The Danish Medical Birth Registry from 1991 to 1996. The drug subsidy system in Danish retail pharmacies, made it possible to identify prescriptions by individual use. All 34,334 prescriptions were set against the Swedish classification of risk of drug use in pregnancy and lactation.

RESULTS

During pregnancy, safe (group A), potentially harmful (group B3, C, and D), and non-classifiable drugs accounted for 40.9%, 26.6% and 28.7% respectively. The proportion of women who redeemed drugs was 29.2%, 8.6%, 18.7% and 0.9% from drug groups A, B, C and D respectively. The proportion of prescriptions from high risk groups declined during the course of pregnancy. Postpartum, safe drugs (group I and II), drugs with possible harmful neonatal effects (group III), and non-classifiable drugs accounted for 43.5%, 4.8%, and 35.8% of the prescriptions, respectively.

CONCLUSION

According to the Swedish classification system, we found that during pregnancy and lactation a high proportion of Danish women were exposed to one or more drugs in high risk groups; furthermore, knowledge regarding their safety for the fetus and neonate was limited for a large proportion of the prescriptions. Current evidence about long-term effects of prenatal exposure stresses the need for long-term follow-up of health and development among exposed children.

Birth outcomes of women with celiac disease: a nationwide historical cohort study

OBJECTIVE

We aimed to examine birthweight, low birthweight (<2500 g), and intrauterine growth retardation in offspring of women with celiac disease in relation to their first hospitalization for the disease.

METHODS

This was a historical cohort study based on The Danish Medical Birth Registry data of celiac women discharged from Danish hospitals from 1977-1992. The study included 211 newborns to 127 mothers with celiac disease, and 1260 control deliveries.

RESULTS

Before celiac women were first hospitalized the mean birthweight of their newborns was 238 g (95% confidence interval [95% CI] = 150, 325 g) lower than that of the control women, after adjustment for potential confounders. After the first hospitalization the mean birthweight for newborns of diseased women was higher than that of controls, by 67 g (95% CI = -88, 223 g) after adjustment for potential confounders. Before celiac women were first hospitalized we found an increased risk of low birthweight (odds ratio [OR] = 2.6, 95% CI = 1.3-5.5) and intrauterine growth retardation (OR = 3.4, 95% CI = 1.6-7.2). After celiac women were first hospitalized we found no increased risk of low birthweight and no babies with intrauterine growth retardation.

CONCLUSIONS

Offspring of mothers with celiac disease had lower birthweight than expected and more than a three-fold higher risk of intrauterine growth retardation when birth occurred before the first hospitalization for the disease. After the mother's first hospitalization the birthweight was similar to controls and no increased risk of low birthweight was seen. Our study indicates that treatment of celiac women is important in the prevention of fetal growth retardation.

Diffusion of new drugs in Danish general practice

OBJECTIVES

There is a large variation in implementing research findings in clinical practice. We examined whether the concept of early or late adopters is universal for the diffusion of all new drugs, and whether it is associated with non-scientific factors in general practice.

METHODS

We identified all prescriptions for five new drugs from the population-based prescription database in North Jutland County, Denmark (490000 inhabitants) from 1993 to 1996, and calculated the period from release of the drugs to the issuing of the first prescription by each GP. Logistic regression was performed to predict early or late prescribing from physician characteristics, practice activity and the number of prescriptions, adjusted for age and sex.

RESULTS

The distributions of the diffusion time of the drugs by 95 solo practitioners were asymmetrical, with a long upper tail representing the late prescribers. The shape and slope of the diffusion curve were highly drug dependent. There was poor agreement of the three adopter categories (early, intermediate and late prescribers) between the five drugs (kappa < 0.35), but being a late prescriber was the most consistent condition. Late prescribing of tramadol, compared with intermediate prescribing, was associated with female physicians (odds ratio (OR) 5.7; 95% CI 1.5-21.3), smaller list size (OR 0.1; 95% CI 0.0-0.8), a strong general restrictive attitude to pharmacotherapy (OR 0.07; 95% CI 0.01-0.68) and a tendency to lower diagnostic activity per patient (OR 0.4; 95% CI 0.1-1.9).

CONCLUSIONS

The slope and shape of the diffusion curve are both dependent on physician and drug characteristics, but late prescribers share some common characteristics.

The safety of proton pump inhibitors in pregnancy

AIM

To assess the safety of proton pump inhibitors during pregnancy.

METHODS

Fifty-one pregnant women exposed to proton pump inhibitors around the time of conception or during pregnancy were compared with 13 327 controls without exposure to any prescribed drug in a population-based study based on The Pharmaco-Epidemiological Prescription Database of North Jutland and the Danish Hospital Discharge Registry.

RESULTS

Three babies with malformations were found among 38 women exposed to proton pump inhibitors from 30 days before conception to the end of the first trimester. No cases of stillbirth were recorded. Crude relative risks of malformation, low birth weight and preterm delivery were 1.6 (95% CI: 0.5-5.1), 1.8 (95% CI: 0.2-13.0) and 2.3 (95% CI: 0.9-6.0), respectively.

CONCLUSIONS

In this population-based follow-up study, we found no substantially elevated risk in terms of malformations, low birth weight or number of preterm deliveries in pregnancies exposed to proton pump inhibitors. However, further monitoring is warranted in order to establish or rule out a potential association between the use of proton pump inhibitors and increased risk of either cardiac malformations or preterm birth.

Long-term prognosis of acute low back pain in patients seen in general practice: a 1-year prospective follow-up study

OBJECTIVES

We aimed to examine the prognosis of acute low back pain (LBP) in patients in general practice and to identify prognostic factors associated with the long-term prognosis based on information immediately available to the GP.

METHOD

We conducted a prospective cohort study in general practice in Denmark. The patients were those aged 18-60 years consulting their GP due to an episode of LBP lasting less than 2 weeks. The GPs collected data regarding 34 exposure variables, including their global assessment of the likelihood of chronic LBP. Outcome variables were collected from the patients after 1, 6 and 12 months. The outcome measures were days on sick leave, and functional or complete recovery from LBP.

RESULTS

In total, 503 (96%) patients were followed during the whole study period. Fifty per cent of the patients on sick leave returned to work within 8 days; after 1 year, only 2% remained on sick leave. At the 1-year follow-up, 45% of the patients continued to complain of LBP. Logistic regression analyses showed that the factors most significantly associated with poor long-term LBP outcome were (i) severity of LBP at inclusion, (ii) assessments by the GP of susceptibility to develop chronic LBP and (iii) a history of LBP having caused previous sick leave.

CONCLUSIONS

LBP in general practice has a good prognosis with regard to sick leave, but a high proportion of patients continue to complain of LBP. We were not able to identify objective measures that strongly predict the prognosis of the individual LBP patient. The overall assessment by the GPs seems to be the most important predictor associated with the long-term outcome.

Historical cohort study of in utero exposure to uterotonic drugs and cognitive function in young adult life

OBJECTIVE

To examine whether in utero exposure to uterotonic drugs effects cognitive performance in draft-age men.

DESIGN

Historical cohort study based on birth registry data and cognitive function measured during evaluations for military service.

SUBJECTS

4300 Danish conscripts born between 1973 and 1975.

MAIN OUTCOME MEASURES

MEAN SCORE IN THE BOERGE PRIEN TEST OF COGNITIVE FUNCTION: score is the number of correct answers to 78 questions and correlates with the full scale intelligence quotient.

RESULTS

The mean Boerge Prien score was similar for those exposed (n=1011) to uterotonic drugs and those not exposed (n=3289), 43.1 versus 42.9 after adjustment for confounders.

CONCLUSION

Our data indicate that exposure to uterotonic drugs does not affect cognitive function 20 years later.

Birth weight and length as predictors for adult height

Adult height has been found to be inversely associated with mortality. Recently, it has been suggested that growth in utero is linked with adult risk of several chronic diseases. The authors examined possible associations between birth weight, birth length, and adult height in young Danish men. They conducted the study in the fifth conscription district of Denmark including all the men born after January 1, 1973 who were residents in the study area during the period August 1, 1993 to July 31, 1994. The Danish Medical Birth Register contains information on all births in Denmark since January 1, 1973. Data on height from the Conscription Register were linked to the Danish Medical Birth Register in 4,300 conscripts examined. Nearly all Danish men have to register with the draft board around age 18 years of age where they undergo a physical examination. There was a strong positive association between birth weight and adult height; for subjects with birth weight < or = 2,500 g, mean height was 175.7 cm, while for those with birth weight > or = 4,501 g, mean height was 184.1 cm. A positive association was also found between birth length and adult height. For subjects with birth length < 47 cm, mean adult height was 175.2 cm, increasing to 184.3 cm at birth length > 56 cm. The associations between birth length and adult height persisted after adjustment for birth weight, gestational age, and other confounders, while the associations between birth weight and adult height almost disappeared when adjusting for birth length and the same confounders. Genetic and/or environmental factors operating both during the pre- and postnatal period may be responsible for the association between birth length and adult height.

A population-based study of antibiotic prescriptions for Danish children

BACKGROUND

The aim of the study was to examine the use of systemic and topical antibiotics in relation to age and sex in Danish children.

METHODS

We used the Pharmacoepidemiological Prescription Database to identify the individual prescriptions of antibiotics provided for all 0-to 15-year-old children in North Jutland County, Denmark, during 1997. The population was approximately 95000 children.

RESULTS

We identified 44640 prescriptions for systemic antibiotics. The annual prescription rate was highest in the 1- to 2-year-olds, with 945 prescriptions/1000 children/year. One-half of these children received at least 1 prescription, and 12% received 3 or more prescriptions. Among the 11- to 15-year-old children 17% received one or more prescriptions. Overall 88% of the prescriptions were penicillins and 10% were macrolides. In children younger than 3 years 57% of prescriptions were for broad spectrum penicillins, but in children older than 6 years penicillin V was the most frequently used antibiotic. We identified 12 661 prescriptions for topical antibiotics used in eye infections. The prescription rate peaked in the 1- to 2-year-old children, one-third of whom received at least 1 prescription.

CONCLUSIONS

Almost two-thirds of the 0- to 2-year-old children in the population were treated with either systemic or topical antibiotics during 1 year. Physicians prescribe mostly penicillins, but the proportion of broad spectrum penicillins for young children was so high, however, that enforcement of national guidelines should be reconsidered.

Drug use in first pregnancy and lactation: a population-based survey among Danish women. The EUROMAP group

OBJECTIVE

To examine the drug prescription pattern in Danish women from 12 weeks prior to conception until 12 weeks post-partum.

METHOD

A drug utilization study based on The North Jutland Prescription Database. The Danish pharmacies use a computerized accounting system for all subsidized drugs and this was linked to the Danish Medical Birth Registry concerning prescription patterns for all women who had given birth in the county of North Jutland from 1991 to 1996.

RESULTS

The analysis included 16,001 primiparous women, who had redeemed 34,834 prescriptions prior to, during and after pregnancy. During pregnancy 44.2% of the women received prescriptions for at least one drug. Users received 2.6 prescriptions on average during pregnancy: 5% of the users redeemed 24.2% of all prescriptions. The proportion of women who redeemed prescriptions for more than three different drugs was 2.7%. The majority of prescriptions were for antibiotics (28.7%), gynaecological drugs (13.3%) and anti-asthma drugs (7.6%). The post-partum prescription proportion was 34.0% and the majority of the prescriptions during this period were for penicillins (20.1%), ophthalmologicals (15.5%) and corticosteroids for dermatological use (5.7%).

CONCLUSION

A high proportion of the women received drugs during pregnancy. The pattern of drug use within the Anatomical Therapeutical Chemical (ATC) groups changed, i.e. the amount of broad spectrum antibiotics decreased and the proportion of prescriptions for local use increased. A small proportion of women redeemed prescriptions for more than three different drugs during pregnancy.

Secular trends in incidence and mortality of bacteraemia in a Danish county 1981-1994

We estimated the incidence and mortality of bacteraemia in the County of North Jutland and examined factors that could explain the changes observed. A population-based survey of bacteraemia was conducted in the Danish County of North Jutland during 1981-1994. Data were retrieved from a regional bacteraemia register. The mortality was determined through linkage to the Danish Civil Registration System. A total of 7198 bacteraemias were detected, and the annual incidence increased from 76 per 100,000 person-years in 1981 to 153 in 1994. One major determining factor was a change in blood culture system with a higher volume of blood per sample, but annual numbers of blood cultures also increased. The 30-day mortality rate increased from 17 to 40 per 100,000 person-years during the study period, whereas the case-fatality rate remained constant (23.6%; 95% confidence intervals 22.6%-24.6%). The number of bacteraemias increased significantly. This observation could be explained only partly by changes in demography, in blood culture system, and in diagnostic activity. The case fatality rate remained constant despite the fact that more people were diagnosed with bacteraemia; this indicates that, with recent blood culture practice, more clinically significant bacteraemias are diagnosed.

Low use of long-term hormone replacement therapy in Denmark

AIMS

To examine individual use of hormone replacement therapy (HRT) in a defined population of Danish women during a 5-year period. HRT may reduce osteoporosis and cardiovascular disease in postmenopausal women, but may also have side-effects. Little is known about the use of HRT in most populations.

METHODS

A Pharmacoepidemiological Prescription Database was used to identify all reimbursed prescriptions for HRT in the county during the period 1991 to 1995. The Danish retail pharmacies' drug subsidy system made it possible to identify prescriptions by individual use.

RESULTS

We examined 255797 HRT prescriptions issued during the period in the County of North Jutland. Total sales reached 16.5 million defined daily doses (DDDs), purchased by 31653 women, which corresponds to 26.9% of the female population above the age of 39 years. The annual prevalence proportion of current users rose from 10.4% to 14.8% during the study period, and the therapeutic intensity (DDD/1000 women/day) increased from 20.6 to 32.0. The mean DDD sum of systemic HRT per user was 73.4 in 1991; it and the proportion of users who received less than 90 DDD per year (83.4% in 1991) remained almost constant during the study period. The amount of oestrogen unopposed by progestin was high, 28.1% of all prescriptions.

CONCLUSIONS

Less than one-fifth of the study population used HRT for more than 3 months per year, and only 32.8% of the women who were new users of HRT in 1992 continued this therapy throughout the study period.

[Birth weight as a predictor of young men's intelligence. A historical cohort study]

The objective was to examine the relation between birth weight and cognitive function in young adult life. The study includes 4300 Danish conscripts born between 1973 and 1975, and the main outcome measure was the mean score in the Børge Prien IQ test at drafting. The score is the number of correct answers to 78 questions and it correlates with full scale intelligence quotient (IQ). Data on birth weight were collected from the birth registry. The mean score in the Børge Prien test increased from 39.9 at a birth weight of < or = 2500 g to 44.6 at a birth weight of 4200 g after adjustment for gestational age and length at birth, maternal age and parity, and other variables. Above a birth weight of 4200 the test score decreased slightly. Birth weight is associated with cognitive performance in young adult life and factors that interference with foetal growth may influence adult cognitive performance.

Changes in liver-derived enzymes and self-reported alcohol consumption. A 1-year follow-up study in Denmark

BACKGROUND

The association between alcohol intake and liver disease is well known, but little is known about alcohol consumption and changes in liver-derived enzymes within 1 year. In a 1-year follow-up study we examined changes in liver-derived enzymes and their association with self-reported alcohol consumption.

METHODS

We recorded liver-derived enzyme values, self-reported alcohol consumption, and potential confounder variables at base line and at a 1-year follow-up in a representative sample of 822 persons (aged 30-50 years) from the survey of The Ebeltoft Health Promotion Project in Denmark, by using questionnaires, health examinations, and blood samples.

RESULTS

The prevalence of increased liver-derived enzyme values was 11.1% at base line and 11.8% at the 1-year follow-up. The incidence rate of increased liver-derived enzyme values was 5.1 per 100 person-years, and 34% of the cases of increased liver-derived enzyme values returned to normal within I year. We found an odds ratio of 4.0 for men and 8.0 for women of developing increased liver-derived enzyme values if alcohol consumption was more than 21 units a week. The risk seemed to be dose-dependent.

CONCLUSIONS

The prevalence of increased liver-derived enzyme values in the population was high and increased slightly during the study period. There was a strong association between the incidence rate of increased liver-derived enzyme values and self-reported alcohol consumption in a dose-dependent relationship, also when adjusted for confounding by smoking and obesity. The persons with persistently increased enzyme values had a higher weekly alcohol consumption than the rest of the study population.

Risk of acute pancreatitis in patients with chronic inflammatory bowel disease. A Danish 16-year nationwide follow-up study

BACKGROUND

There are few epidemiologic data about the risk of acute pancreatitis in chronic inflammatory bowel diseases; we therefore wanted to estimate the risk of a first episode of acute pancreatitis in patients with Crohn's disease and ulcerative colitis in the total Danish population.

METHODS

The study included all patients discharged from Danish hospitals with a diagnosis of Crohn's disease or ulcerative colitis registered in the Danish National Registry of Patients in the period from 1977 to 1992. The first episode of acute pancreatitis was identified in the cohort. The observed number of patients with acute pancreatitis was compared with expected numbers on the basis of age, sex, and calendar-specific incidence rates in the general population.

RESULTS

Overall, 15,526 patients were discharged and followed up for 112,824 person-years. The standardized incidence ratio (SIR) for acute pancreatitis was increased both in patients with Crohn's disease (SIR = 4.3; 95% confidence interval (CI), 2.9-6.1) and in those with ulcerative colitis (SIR= 2.1; 95% CI, 1.6-2.8).

CONCLUSION

Patients with chronic inflammatory bowel disease seem to be at increased risk of acute pancreatitis. Further validation and refinement of this registration-based study are needed.

Lipid-lowering medication and risk of cancer

Low or declining levels of serum cholesterol have been associated with increased mortality from cancer. We conducted a population-based cohort study of 1882 patients from one Danish county who received lipid-lowering drugs between January 1, 1991 and December 31, 1994. During the follow-up period of up to 4 years, 41 cancers were observed among users of lipid-lowering drugs, with 42.9 expected, to yield an age- and sex-standardized incidence ratio of 1.0 (95% confidence interval, 0.7-1.3). Although limited by small numbers and short follow-up period, examination by site of cancer and type of drug provided no evidence of an association. Further research is needed, however, with longer follow-up to assess more fully any potential cancer risk with these medications.

Risk of resistance related to antibiotic use before admission in patients with community-acquired bacteraemia

We analysed the association of antibiotic therapy before admission and antibiotic resistance of blood isolates in a total of 1717 community-acquired bacteraemias in the County of Northern Jutland during 1992-96. Antibiotics had been prescribed to 14% of the patients during the 30 days before admission and to 37% during the 6 months. The most frequently prescribed antibiotics within 30 days were ampicillin (28%), penicillin G (27%), sulphonamides and/or trimethoprim (16%) and macrolides (14%). The most frequent blood isolates were Escherichia coli (33%), other Enterobacteriaceae (8%), Streptococcus pneumoniae (23%) and Staphylococcus aureus (10%). Of the 575 isolates of E. coli, 425 (74%), 432 (75%) and 518 (90%) were susceptible to ampicillin, sulphonamides and trimethoprim, respectively. Previous antibiotic prescriptions were strongly associated with resistance to ampicillin, sulphonamides and trimethoprim in E. coli. The association was less pronounced for S. aureus and enteric rods other than E. coli. Antibiotic prescriptions within the last 3 months predicted antibiotic resistance, and this should be taken into account when selecting empirical antibiotic therapy of severe community-acquired infections.