IMPORTANCE Intracerebral hemorrhage (ICH) during pregnancy and the postpartum period results in catastrophic maternal outcomes. There is a paucity of population-based estimates of pregnancyrelated ICH risk, including risk during the extended postpartum period. OBJECTIVE To evaluate ICH risk during pregnancy and an extended 24-week postpartum period in a population-level cohort and to determine fetal and maternal outcomes as well as demographic and comorbidity factors associated with ICH during pregnancy and post partum. DESIGN, SETTING, AND PARTICIPANTS This study used a cohort-crossover design in which patients serve as their own controls when no longer exposed (pregnant or post partum). Administrative data were obtained from all hospital admissions for New York, California, and Florida for a 7-to 10-year period. Participants included all women admitted for labor and delivery who were older than 12 years and did not have a prior diagnosis of ICH. Conditional Poisson regression models were used to evaluate ICH risk, and data were reported as rate ratios and 95% CIs. Data analysis was performed from August 2018 to February 2020. EXPOSURES Women were tracked using hospitalization records for the duration of pregnancy (40 weeks), for 24 weeks post partum, and for an additional 64 weeks when no longer exposed. MAIN OUTCOMES AND MEASURES Diagnosis of ICH during both 64-week observation periods was determined using validated International Classification of Diseases, Ninth Revision codes. RESULTS A total of 3 314 945 pregnant women were included (mean [SD] age, 28.17 [6.47] years; 1 451 780 white [43.79%], 474 808 black [14.32%], 246 789 Asian [7.44%], and 835 917 Hispanic [25.22%]). The risk of ICH was significantly higher during the third trimester (2.9 vs 0.7 cases per 100 000 pregnancies; rate ratio, 4.16; 95% CI, 2.52-6.86) and remained elevated during the first 12 weeks post partum (4.4 vs 0.5 cases per 100 000 pregnancies; rate ratio, 9.15; 95% CI, 5.16-16.23).

Background: The Nationwide Inpatient Sample (NIS) represents 90% of US hospitalizations. Beginning fourth quarter (Q4) 2015, NIS transitioned to ICD 10. ICD 10 codes for Intracerebral Hemorrhage (ICH) are hemorrhage location specific, which may predict outcomes. We examine the utilization of ICD 10 codes for ICH patients across various demographic, hospital, and disease severity factors in Q4 2015 and 2016 NIS. We report factors associated with use of non-specific codes (NSC) and assess potential coding validation based on expectations of in-hospital mortality (IHM). Methods: We used ICD 10 codes (i610-16, i618-19) to identify non-traumatic ICH discharges. We categorized hemorrhage locations as (1) Hemispheric (cortical or subcortical) [i610-12], (2) Brain Stem or Cerebellar [i613-14], (3) Intraventricular Hemorrhage (IVH) [i615], (4) Multiple Localized [i616], and (5) Other and Not Specified [i618-19]. We considered ‘Other and Not Specified’ category as NSC and fit survey design logistic regression models for factors associated with NSC. Results: We identified 79, 290 ICH discharges of which 38.9% were NSC. Proportion of discharges by lCH location and corresponding IHM is shown in Figure 1. Highest IHM was observed for IVH. In the fully adjusted model advanced age and white race (vs. African American) were independently associated with higher NSC use. ICH discharges from urban teaching hospitals were less likely to be NSC as compared to rural hospitals (OR, 95% CI: 0.7, 0.6 - 0.8). Patients discharged from large and medium size hospitals were 28% and 17% more likely to be provided a specific code as compared to smaller hospitals. Hospitals in Northeast US were more likely to use NSC. Conclusion: ICD 10 codes provide an opportunity for risk adjustment in administrative data for ICH, we demonstrate that up to 40% of discharges had NSC which is more prevalent in smaller/rural/Northeast hospitals. Our work sets a foundation for examining bias caused by NSC in future studies.

Background: Prior observational studies suggest lower in-hospital mortality (IHM) among intracerebral hemorrhage (ICH) patients treated at higher levels of care (LOC). However, comparisons across non-certified (NC), primary certified (PSC), and comprehensive certified centers (CSC) have not been reported; particularly accounting for changing certification status. Also, unmeasured confounding in observational designs can bias estimates. We performed an instrumental variable (IV) analysis of population level TX state data for association between IHM and LOC. Methods: We analyzed TX in-patient discharges for years 2010 - 2015. Adult, non-traumatic and non-transferred ICH discharges were tagged using ICD-9 codes. Patients’ location was estimated using population weighted centroid for their zip code. Hospitals’ location was geo-coded and certification status (by quarter) was determined from publicly available data. The differential distance of the patient to their closest certified hospital vs closest NC hospital was used as a ‘randomization’ variable (IV). We tested for IV strength and its association with risk of mortality. The IV model was a 2-stage least squares regression (2-SLSR). We report exponentiated IV estimator (IVE) and 95% CI. Results: Based on our criteria and non-missing data, 18,178 discharges were included, mean (SD) age 67.7 (15.5), 50.2% female, 60.0% White and 27.7% Hispanic. Overall, 46.1% discharges were from certified hospitals and IHM was 24.6%. The 2-SLSR demonstrated a significantly lower IHM for ICH discharges from certified hospitals as compared to NC hospitals (IVE, CI: 0.80, 0.74 - 0.97). However, this effect was not observed for comparison between PSC and CSC hospitals (IVE, CI: 0.98, 0.82 - 1.17). The F-static for IV strength was 118 and 249 (recommended > 10). The IV was neither associated with outcome (IHM) nor with measured confounders (severity of illness, age). Conclusion: In a state with large urban - rural divide, IHM reduction was associated with care of ICH patients at certified hospitals. However, similar benefits were not observed across two levels of certification. Factors leading to reduced IHM at certified hospitals need to be studied further and incorporated in health systems redesign for ICH patients.