BackgroundThe Swedish National Inpatient Register (IPR), also called the Hospital Discharge Register, is a principal source of data for numerous research projects. The IPR is part of the National Patient Register. The Swedish IPR was launched in 1964 (psychiatric diagnoses from 1973) but complete coverage did not begin until 1987. Currently, more than 99% of all somatic (including surgery) and psychiatric hospital discharges are registered in the IPR. A previous validation of the IPR by the National Board of Health and Welfare showed that 85-95% of all diagnoses in the IPR are valid. The current paper describes the history, structure, coverage and quality of the Swedish IPR.Methods and resultsIn January 2010, we searched the medical databases, Medline and HighWire, using the search algorithm "validat* (inpatient or hospital discharge) Sweden". We also contacted 218 members of the Swedish Society of Epidemiology and an additional 201 medical researchers to identify papers that had validated the IPR. In total, 132 papers were reviewed. The positive predictive value (PPV) was found to differ between diagnoses in the IPR, but is generally 85-95%.ConclusionsIn conclusion, the validity of the Swedish IPR is high for many but not all diagnoses. The long follow-up makes the register particularly suitable for large-scale population-based research, but for certain research areas the use of other health registers, such as the Swedish Cancer Register, may be more suitable.

The new register provides valuable data on exposure to drugs and is useful to study patterns of drug utilization. The possibilities for record linkage to other health registers gives from an international perspective good opportunities to explore drug and disease associations and the risks, benefits, effectiveness and health economical effects of drug use.

Context Up-to-date information on infant survival after extremely preterm birth is needed for assessing perinatal care services, clinical guidelines, and parental counseling. Objective To determine the 1-year survival in all infants born before 27 gestational weeks in Sweden during 2004-2007. Design, Setting, and Patients Population-based prospective observational study of extremely preterm infants (707 live-born and 304 stillbirths) born to 887 mothers in 904 deliveries (102 multiple births) in all obstetric and neonatal units in Sweden from April 1, 2004, to March 31, 2007. Main Outcome Measures Infant survival to 365 days and survival without major neonatal morbidity (intraventricular hemorrhage grade Ͼ2, retinopathy of prematurity stage Ͼ2, periventricular leukomalacia, necrotizing enterocolitis, severe bronchopulmonary dysplasia). Associations between perinatal interventions and survival. Results The incidence of extreme prematurity was 3.3 per 1000 infants. Overall perinatal mortality was 45% (from 93% at 22 weeks to 24% at 26 weeks), with 30% stillbirths, including 6.5% intrapartum deaths. Of live-born infants, 91% were admitted to neonatal intensive care and 70% survived to 1 year of age (95% confidence interval [CI], 67%-73%). The Kaplan-Meier survival estimates for 22, 23, 24, 25, and 26 weeks were 9.8% (95% CI, 4%-23%), 53% (95% CI, 44%-63%), 67% (95% CI, 59%-75%), 82% (95% CI, 76%-87%), and 85% (95% CI, 81%-90%), respectively. Lower risk of infant death was associated with tocolytic treatment (adjusted for gestational age odds ratio [OR], 0.43; 95% CI, 0.36-0.52), antenatal corticosteroids (OR, 0.44; 95% CI, 0.24-0.81), surfactant treatment within 2 hours after birth (OR, 0.47; 95% CI, 0.32-0.71), and birth at a level III hospital (OR, 0.49; 95% CI, 0.32-0.75). Among 1-year survivors, 45% had no major neonatal morbidity. Conclusion During 2004 to 2007, 1-year survival of infants born alive at 22 to 26 weeks of gestation in Sweden was 70% and ranged from 9.8% at 22 weeks to 85% at 26 weeks.

BACKGROUND: Maternal use of selective serotonin re-uptake inhibitors (SSRIs) has recently been associated with an increased risk for certain malformations. METHODS: Using the Swedish Medical Birth Register, we identified women who had reported the use of SSRIs in early pregnancy and studied their infants, born between July 1, 1995 and the end of 2004. Congenital malformations were identified from that register, from the Register of Congenital Malformations, and from the Hospital Discharge Register. The effect of drug exposure was studied after adjustment for a number of identified maternal characteristics that could act as confounders. RESULTS: We identified 6,481 women who reported the use of SSRIs in early pregnancy and their 6,555 infants. There was no general increase in malformation risk. An increased risk for cystic kidneys was seen, but this was based on only nine malformed infants, and the pathology varied between these cases. An in-depth study of cardiovascular defects identified an association between such defects and notably ventricular and atrial septum defects and maternal use of paroxetine but not other SSRIs. No support for a postulated association between SSRI use and infant craniostenosis or omphalocele was found. CONCLUSIONS: Use of SSRIs in early pregnancy does not seem to be a major risk factor for infant malformations. The association between paroxetine use and infant cardiovascular defects may be a result of multiple testing, but is supported by other studies.

An increased risk for congenital malformations occurs after IVF, similar for the different IVF techniques used, and mainly a consequence of parental characteristics. A few specific conditions show an extra increase in risk.