Linked birth cohort files for perinatal health research: California as a model for methodology and implementation.

PURPOSE: Rigorous perinatal epidemiologic research depends on population-based parental and neonatal sociodemographic and clinical data. Here we describe the creation of linked birth cohort files, an enriched data source that combines information from vital records with maternal delivery and infant hospital encounter records. METHODS: Probabilistic linkage techniques were used to link vital records (i.e., birth and fetal death certificates) from the California Department of Public Health with hospital inpatient, ambulatory surgery and emergency department encounter data for mothers and infants from the California Department of Health Care Access and Information. RESULTS: From 2012 to 2018, 95% of live birth records were successfully linked to maternal and newborn hospital records while 85% of fetal death records were linked to a maternal delivery record. Overall, 93% of postnatal hospital encounters of infants (i.e., <1 year old) were matched to a linked record. CONCLUSIONS: The linked birth cohort files is a rich resource opening many possibilities for understanding perinatal health outcomes and opportunities for linkage to longitudinal, social determinant, and environmental data. To optimally use this file for research, analysts should evaluate possible shortcomings or biases of the data sources being linked.

Use of Statewide Administrative Data to Assess Clinical Outcomes: A Retrospective Cohort Study of Therapeutic Anticoagulation for Isolated Calf Vein Thrombosis.

BACKGROUND: Single-center comparative effectiveness studies evaluating outcomes that can occur posthospitalization may become biased if outcomes diagnosed at other facilities are not ascertained. Administrative datasets that link patients' records across facilities may improve outcome ascertainment. OBJECTIVE: To determine whether use of linked administrative data significantly augments thromboembolic outcome ascertainment. RESEARCH DESIGN: Retrospective cohort study. SUBJECTS: Patients with an acute isolated calf deep vein thrombosis (DVT) diagnosed at 1 Californian center during 2010-2013. MEASURES: Proximal DVT or pulmonary embolism (PE) within 180 days. We ascertained outcomes from linked California hospitalization, emergency department, and ambulatory surgery data and compared this information to outcomes previously identified from review of the center's medical records. RESULTS: Among 384 patients with an isolated calf DVT, 333 could be linked to longitudinal administrative data records. Ten patients had a possible proximal DVT or PE (4 more clearly so) from administrative data; all were unknown from medical record review. Eleven patients with known outcomes from medical record review had no outcome from administrative data. The adjusted odds ratio of proximal DVT or PE with therapeutic anticoagulation attenuated from 0.33 [95% confidence interval (CI), 0.12-0.87] using only medical record review to 0.64 (95% CI, 0.29-1.40) using both medical record review and possible outcomes from administrative data. Restricting the outcome to diagnoses clearly involving proximal DVT or PE, the adjusted odds ratio was 0.46 (95% CI, 0.19-1.10). CONCLUSIONS: Use of linked hospital administrative data augmented detection of outcomes but imperfect linkage, nonspecific diagnoses, and documentation/coding errors introduced uncertainty regarding the accuracy of outcome ascertainment.

A quality improvement project to increase breast milk use in very low birth weight infants.

OBJECTIVE: To evaluate a multihospital collaborative designed to increase breast milk feeding in premature infants. METHODS: Eleven NICUs in the California Perinatal Quality of Care Collaborative participated in an Institute for Healthcare Improvement-style collaborative to increase NICU breast milk feeding rates. Multiple interventions were recommended with participating sites implementing a self-selected combination of these interventions. Breast milk feeding rates were compared between baseline (October 2008-September 2009), implementation (October 2009-September 2010), and sustainability periods (October 2010-March 2011). Secondary outcome measures included necrotizing enterocolitis (NEC) rates and lengths of stay. California Perinatal Quality of Care Collaborative hospitals not participating in the project served as a control population. RESULTS: The breast milk feeding rate in the intervention sites improved from baseline (54.6%) to intervention period (61.7%; P = .005) with sustained improvement over 6 months postintervention (64.0%; P = .003). NEC rates decreased from baseline (7.0%) to intervention period (4.3%; P = .022) to sustainability period (2.4%; P < .0001). Length of stay increased during the intervention but returned to baseline levels in the sustainability period. Control hospitals had higher rates of breast milk feeding at baseline (64.2% control vs 54.6% participants, P < .0001), but over the course of the implementation (65.7% vs 61.7%, P = .049) and sustainability periods (67.7% vs 64.0%, P = .199), participants improved to similar rates as the control group. CONCLUSIONS: Implementation of a breast milk/nutrition change package by an 11-site collaborative resulted in an increase in breast milk feeding and decrease in NEC that was sustained over an 18-month period.

Promoting antenatal steroid use for fetal maturation: results from the California Perinatal Quality Care Collaborative.

OBJECTIVE: The California Perinatal Quality Care Collaborative (CPQCC) was formed to seek perinatal care improvements by creating a confidential multi-institutional database to identify topics for quality improvement (QI). We aimed to evaluate this approach by assessing antenatal steroid administration before preterm (24 to 33 weeks of gestation) delivery. We hypothesized that mean performance would improve and the number of centers performing below the lowest quartile of the baseline year would decrease. STUDY DESIGN: In 1998, a statewide QI cycle targeting antenatal steroid use was announced, calling for the evaluation of the 1998 baseline data, dissemination of recommended interventions using member-developed educational materials, and presentations to California neonatologists in 1999-2000. Postintervention data were assessed for the year 2001 and publicly released in 2003. A total of 25 centers voluntarily participated in the intervention. RESULTS: Antenatal steroid administration rate increased from 76% of 1524 infants in 1998 to 86% of 1475 infants in 2001 (P < .001). In 2001, 23 of 25 hospitals exceeded the 1998 lower-quartile cutoff point of 69.3%. CONCLUSIONS: Regional collaborations represent an effective strategy for improving the quality of perinatal care.

Psychiatric and substance use disorders as risk factors for low birth weight and preterm delivery.

OBJECTIVE: We examined the associations between psychiatric and substance use diagnoses and low birth weight (LBW), very low birth weight (VLBW), and preterm delivery among all women delivering in California hospitals during 1995. METHODS: This population-based retrospective cohort analysis used linked hospital discharge and birth certificate data for 521,490 deliveries. Logistic regression analyses were conducted to assess the associations between maternal psychiatric and substance use hospital discharge diagnoses and LBW, VLBW, and preterm delivery while controlling for maternal demographic and medical characteristics. RESULTS: Women with psychiatric diagnoses had a significantly higher risk of LBW (adjusted odds ratio [OR] 2.0; 95% confidence interval [CI] 1.7, 2.3), VLBW (OR 2.9; 95% CI 2.1, 3.9), and preterm delivery (OR 1.6; 95% CI 1.4, 1.9) compared with women without those diagnoses. Substance use diagnoses were also associated with higher risk of LBW (OR 3.7; 95% CI 3.4, 4.0), VLBW (OR 2.8; 95% CI 2.3, 3.3), and preterm delivery (OR 2.4; 95% CI 2.3, 2.6). CONCLUSION: Maternal psychiatric and substance use diagnoses were independently associated with low birth weight and preterm delivery in the population of women delivering in California in 1995. Identifying pregnant women with current psychiatric disorders and increased monitoring for preterm and low birth weight delivery among this population may be indicated.