Kristensen Fb

Validation of the danish birth registration

We assessed validity and reliability of data on four serious pregnancy complications and gestational age in two national registers, the Medical Birth Register (MBR) and the National Register of Hospital Discharges (NRHD). From a cohort of all women in Denmark who gave birth to their first and second singleton infant in 1982-1987, a review was made of a selected sample of 1662 medical records. Regarding registration of pregnancy complications, there was good agreement (kappa above 0.6) between medical records and the registers, and between the registers. However, there was a tendency toward understatement evidenced by low sensitivity of three of four pregnancy complications. The level of agreement (43%) for length of gestation was disappointing. The number of systematic and nonsystematic errors indicate that there was about 52% more singleton preterm deliveries in Denmark in 1982 than previously reported (6.9% instead of 4.5%). It is concluded that the validity of the Danish birth registers should be improved by explicit definitions, increased use of raw data, and data collection by motivated professionals at birth.

Implications of idiopathic preterm delivery for previous and subsequent pregnancies

Objective To describe the relationship between pregnancy complications and fetal outcome in first and second pregnancies, focusing on idiopathic and indicated preterm birth of singleton infants in either pregnancy. Methods Included in the study were 13,967 women in Denmark who gave birth to their first singleton infant in 1982 and a second infant in 1982–1987. Information on pregnancy and birth was obtained by linking the National Medical Birth Register and the National Register of Hospital Discharges, based on personal identification numbers. Results The risk of a preterm second birth in women with idiopathic and indicated preterm first birth did not differ significantly (15.2 and 12.8%, respectively). However, women with idiopathic preterm birth in the first pregnancy tended to repeat idiopathic preterm birth twice as often as women with indicated preterm birth repeated indicated preterm birth (11.3 versus 6.4%). Adjustment by logistic regression analysis for other risk factors for preterm birth did not influence the relative risk (6.0 before 32 weeks and 4.8 for 32–36 weeks) of a second preterm birth after a first preterm birth. Women with idiopathic preterm delivery in their first and second pregnancies gave birth to infants with lower birth weight than in previous or subsequent pregnancies. Emergency cesarean delivery in a first term pregnancy was a risk factor for subsequent idiopathic preterm birth. Conclusion Idiopathic preterm birth is associated with emergency cesarean delivery at term in previous pregnancies and infants with lower birth weight in previous and subsequent pregnancies.

Peer Comparison Feedback to Achieve Rational and Economical Drug Therapy in General Practice: A Controlled Intervention Study

The aim of the study was to describe and evaluate a controlled intervention to achieve more rational and economical drug therapy in general practice. The strategy was based on peer comparison feedback and encouragement of local peer group discussions. Seven districts comprising 53, and 6 districts comprising 55 eligible practices constituted the intervention and control groups respectively. The process was evaluated by questionnaires to the GPs. 88% found the feedback diagrams relevant, and 74% expressed a wish for information about prescribing of particular drugs. The outcome evaluation was based on computerized registration of prescriptions. During the study period of 6 months the median costs per prescription increased significantly in the control group, whereas there was no statistically significant change in the intervention group. There were no significant effects on the prescribed amounts.

Idiopathic preterm deliveries in Denmark

Objective To characterize and quantify various demographic factors in idiopathic preterm delivery. Methods All women with a permanent address in Denmark and a singleton pregnancy who gave birth to a preterm infant in 1982 (N = 51,851) were included. The material was obtained by a linkage of the Medical Birth Register and the National Register of Hospital Discharges, using personal identification numbers. Results The incidence of singleton preterm delivery was 4.5% (N = 2330), of which 67% (N = 1557) were idiopathic. The neonatal mortality rate was significantly lower with idiopathic than with indicated preterm birth. Following stepwise logistic regression analysis, age under 20 (adjusted odds ratio [OR] 1.63, 95% confidence interval [CI] 1.07–2.47; P < .03), age above 30 (adjusted OR 0.74, 95% CI 0.60–0.90; P < .004) and being married (adjusted OR 0.63, 95% CI 0.43–0.94; P < .03) correlated with idiopathic preterm birth. Conclusion Idiopathic preterm birth is more common in single, young women and is associated with a lower neonatal mortality rate than indicated preterm birth.