Nighttime delivery and risk of neonatal encephalopathy.

OBJECTIVE: The objective of the study was to determine the relationship between nighttime delivery and neonatal encephalopathy (NE). STUDY DESIGN: The design of the study was a retrospective population-based cohort of 1,864,766 newborns at a gestation of 36 weeks or longer in California, 1999-2002. We determined the risk of NE associated with nighttime delivery (7:00 (PM) to 6:59 (AM)). RESULTS: Two thousand one hundred thirty-one patients had NE (incidence 1.1 per 1000 births). Nighttime delivery was associated with increased NE (odds ratio [OR], 1.13; 95% confidence interval [CI], 1.03-1.20), birth asphyxia (OR, 1.18; 95% CI, 1.08-1.29), and neonatal seizures (OR, 1.17; 95% CI, 1.07-1.28). In adjusted analyses, nighttime delivery was an independent risk factor for NE (OR, 1.10; 95% CI, 1.01-1.21), as were severe intrauterine growth retardation (OR, 3.8; 95% CI, 3.1-4.8); no prenatal care (OR, 2.0; 95% CI, 1.4-2.9); primiparity (OR, 1.5; 95% CI, 1.4-1.7); advanced maternal age (OR, 1.3; 95% CI, 1.16-1.45); and infant male sex (OR, 1.3; 95% CI, 1.2-1.4). CONCLUSION: Future studies of time of delivery may generate new strategies to reduce the burden of NE.

Antenatal and intrapartum risk factors for seizures in term newborns: a population-based study, California 1998-2002.

OBJECTIVE: To assess antenatal and intrapartum risk factors for seizures occurring during the birth admission. STUDY DESIGN: Using multivariable logistic regression analysis, we evaluated the association between maternal characteristics and birth admission seizures in a cohort of 2.3 million California children born at >or=36 weeks' gestation between 1998 and 2002 using the California Office of Statewide Planning and Development database containing birth certificates linked to infant and maternal hospital discharge abstracts. RESULTS: The incidence of seizures during the birth admission was 0.95/1000 live births. In an adjusted analysis, infants of women age 40 years and older who were nulliparous; had diabetes mellitus, intrapartum fever, or infection or delivered at >or=42 weeks had an increased risk of seizures. Infants of Hispanic and Asian mothers had a lower risk compared with infants of Caucasian mothers. CONCLUSIONS: Several maternal antenatal and intrapartum factors increased the risk of seizures during the birth admission. Identifying and avoiding risks for neonatal seizures may lead to lower infant neurologic morbidity and mortality.

Higher ABCD2 score predicts patients most likely to have true transient ischemic attack.

BACKGROUND AND PURPOSE: Some patients diagnosed with transient ischemic attack (TIA) in the emergency department may actually have alternative diagnoses such as seizure, migraine, or other nonvascular spells. The ABCD2 score has been shown to predict subsequent risk of stroke in patients with TIA diagnosed by emergency physicians, but perhaps high ABCD2 scores simply separate those patients with true TIA from those with alternative diagnoses. We investigated this hypothesis in a cohort of patients with TIA identified in the emergency department whose records were reviewed by an expert neurologist. METHODS: Among patients diagnosed by emergency physicians with TIA in 16 hospitals in the Kaiser-Permanente Medical Care Plan over a 1-year period ending February 1998 (before publication of prediction rules), an expert neurologist reviewed all records for those in which the diagnosis of TIA was considered questionable by a medical records analyst and determined whether the spell was likely to represent a true TIA. Subsequent strokes within 90 days were identified. ABCD2 scores were calculated for all patients and 2-sided Cochrane-Armitage trend tests were used to assess subsequent risk of stroke. RESULTS: Of the 713 patients reviewed by the expert neurologist, 642 (90%) were judged to likely have experienced a true TIA. Ninety-day stroke risk was 24% (95% CI, 20% to 27%) in the group judged to have experienced a true TIA and 1.4% (0% to 7.6%) in the group judged to not have a true TIA (P<0.0001). ABCD(2) scores were higher in those judged to have a true TIA compared with others (P=0.0001). In the group judged to have a true TIA, 90-day stroke risk increased as ABCD2 score increased (P<0.0001); there was no relationship between ABCD2 score and stroke risk in those judged unlikely to have had a TIA (P=0.73). CONCLUSIONS: Among patients diagnosed by emergency department physicians with TIA, higher ABCD2 score was associated with a greater likelihood that the diagnosis was confirmed on expert review. The predictive power of the ABCD2 model is therefore partially explained by identification of those patients likely to have experienced a true TIA, an important aspect of the score when used by nonneurologists. However, higher ABCD2 scores still remained predictive of 90-day stroke rate in the group of patients judged to have a true TIA by an expert neurologist.

Factors associated with the decision to hospitalize patients after transient ischemic attack before publication of prediction rules.

BACKGROUND AND PURPOSE: One important criterion for hospitalizing patients after transient ischemic attack (TIA) is the short-term risk of stroke. Before publication of prediction rules for stroke after TIA, physician judgment was required to make a decision about hospitalization. We sought to identify factors associated with the decision to admit patients with TIA from the emergency department (ED) and to see whether those at highest risk of stroke were selected for admission. METHODS: All patients diagnosed with TIA in the ED of 16 hospitals in the Kaiser-Permanente Medical Care Plan over a 1-year period before publication of prediction rules were included (n=1707). Risk of subsequent stroke was stratified according to a validated prediction rule (ABCD(2) score), and the decision to admit was correlated with these risk scores. Factors associated with admission in univariate analysis were included in a logistic regression model. RESULTS: Overall, 243 patients with TIA (14%) were admitted. Admission weakly correlated with the ABCD(2) score (rank biserial R(2)=0.036; 10.0% at low 2-day risk of stroke admitted versus 20.3% at high risk). Seven variables were independently associated with a decision to admit after TIA: prior TIA, speech impairment, weakness, gait disturbance, history of atrial fibrillation, symptoms on arrival to ED, and use of ticlopidine. CONCLUSIONS: In this cohort of patients with TIA, the decision to admit was weakly correlated with risk of subsequent stroke as measured by the ABCD(2) score, and several risk factors for stroke were not important for the decision to admit. Before publication of prediction rules for stroke after TIA, physicians were not identifying the majority of patients at highest risk of stroke for admission.