Beate Danielsen

Childbearing beyond age 40: Pregnancy outcome in 24,032 cases

OBJECTIVE To examine pregnancy outcomes in women age 40 or older. METHODS We used data from the California Health Information for Policy Project, which consists of linked records from the birth certificate and the hospital discharge record of both mother and newborn of all births that occurred in acute care civilian hospitals in California between January 1, 1992, and December 31, 1993. The study population consisted of all women who delivered at age 40 or over. The control population was women who delivered between age 20 and 29 years during this 2-year period. We reviewed gestational age at delivery, birth weight, mode and type of delivery, discharge summary and birth certificate demographics, birth outcome, pregnancy, and delivery data. RESULTS Approximately 1,160,000 women delivered during the study period, and 24,032 (2%) of these women were age 40 or older. Of this latter group, 4777 (20%) were nulliparous. The cesarean delivery rate for nulliparous women in the study population was 47.0%, and the rate for multiparous patients in this group was 29.6%. The cesarean delivery rate was 22.5% for nulliparous and 17.8% for multiparous women in the control group. In the older group, the operative vaginal delivery rate (forceps and vacuum) was 14.2% for nulliparous women and 6.3% for multiparous women. Rates of birth asphyxia, fetal growth restriction, malpresentation, and gestational diabetes were significantly higher among older nulliparas (6, 2.5, 11, and 7%, respectively) compared with rates among control nulliparas (4, 1.4, 6, and 1.7%, respectively), and there were similar significant increases among older multiparas (3.4, 1.4, 6.9, and 7.8%, respectively), compared with younger multiparous controls (2.4, 1, 3.7, and 1.6%, respectively). Mean (+/- standard error) birth weight of infants delivered by older nulliparous women was 3201+/-10 g, significantly lower than that among nulliparous controls (3317+/-1 g), whereas mean birth weight in the group of older multiparas (3381+/-5 g) was no different than that among younger multiparous controls (3387+/-1 g). Gestational age at delivery was significantly lower among older nulliparas (273.4+/-0.4 days), compared with nulliparous controls (278.5+/-0.05 days), and similarly lower among older multiparous women (274.0+/-0.2 days), compared with multiparous controls (278.3+/-0.05 days). More white women age 40 or over than younger white women were having a first child (64 and 39%, respectively). CONCLUSION Nulliparous women age 40 or over have a higher risk of operative delivery (cesarean, forceps, and vacuum deliveries: 61%) than do younger nulliparous women (35%). This increase occurs in spite of lower birth weight and gestational age and may be explained largely by the increase in other complications of pregnancy. The increased frequency at which white women are having their first child at age 40 or over may reflect career choices that involve delaying childbirth until the fifth decade of life. These data will allow us better to counsel patients about their pregnancy expectations and possible outcomes.

Obstetric anal sphincter lacerations.

OBJECTIVE To estimate the frequency of obstetric anal sphincter laceration and to identify characteristics associated with this complication, including modifiable risk factors. METHODS A population‐based, retrospective study of over 2 million vaginal deliveries at California hospitals was performed, using information from birth certificates and discharge summaries for 1992 through 1997. We excluded preterm births, stillbirths, breech deliveries, and multiple gestations. The main outcome measure was obstetric anal sphincter laceration (third and fourth degree). RESULTS The frequency of anal sphincter lacerations was 5.85% (95% confidence interval [CI] 5.82, 5.88), decreasing significantly from 6.35% (95% CI 6.27, 6.43) in 1992 to 5.43% (95% CI 5.35, 5.51) in 1997 (P < .01). Using logistic regression analysis, we identified primiparity as the dominant risk factor (odds ratio [OR] for women with prior vaginal birth 0.15; 95% CI 0.14, 0.15). Birth weight over 4000 g was also highly significant (OR 2.17; 95% CI 2.07, 2.27). Lacerations occurred more often among women of certain racial and ethnic groups: Indian women (OR 2.5; 95% CI 2.23, 2.79) and Filipina women (OR 1.63; 95% CI 1.50, 1.77) were at highest risk. Episiotomy decreased the likelihood of third‐degree lacerations (OR 0.81; 95% CI 0.78, 0.85), but increased the risk of fourth‐degree lacerations (OR 1.12; 95% CI 1.05, 1.19). Operative delivery increased the risk of sphincter laceration, with vacuum delivery (OR 2.30; 95% CI 2.21, 2.40) presenting a greater risk than forceps delivery (OR 1.45; 95% CI 1.37, 1.52). CONCLUSION Anal sphincter lacerations are strongly associated with primiparity, macrosomia, and operative vaginal delivery. Of the modifiable risk factors, operative vaginal delivery remains the dominant independent variable.

Acute myocardial infarction in pregnancy and the puerperium: a population-based study.

OBJECTIVE: To estimate the population-based incidence and pregnancy outcomes of acute myocardial infarction (MI) in pregnancy. METHODS: Maternal and newborn hospital discharge records were linked to birth/death certificates for the 10-year period January 1, 1991, to December 30, 2000, for the majority (98%) of deliveries in California. This database was searched for the diagnosis of acute MI, demographic characteristics, and pregnancy outcomes. Patients were divided into 4 groups: antenatal diagnosis, intrapartum diagnosis, up to 6-week postpartum diagnosis, and those without the diagnosis of acute MI. All groups were compared by Student t test or χ2 or both, where appropriate. RESULTS: A total of 151 women had an acute MI during the antepartum (38%), intrapartum (21%), or 6-week postpartum (41%) period, giving an incidence rate of 1 in 35,700 deliveries. The incidence rate increased over the study period. The maternal mortality rate was 7.3%, and maternal death only occurred in women with an acute MI before or at delivery (P < .01). Compared with women who did not have an acute MI, those with one were more likely to be older (30% were older than 35 years compared with 10%), multiparous (78% compared with 61%), non-Hispanic white (40% compared with 35%) or African Americans (15% compared with 7%). All measures of maternal and neonatal morbidity were increased in the acute MI group compared with those without an acute MI. Multivariate analysis identified chronic hypertension, diabetes, advancing maternal age, eclampsia, and severe preeclampsia as independent risk factors for acute MI. CONCLUSION: Acute MI during pregnancy remains a rare event, with significant maternal, fetal, and neonatal morbidity and mortality and maternal mortality limited to the antepartum and intrapartum period. LEVEL OF EVIDENCE: III

Malignant melanoma in pregnancy. A population-based evaluation.

For many years, there has been controversy in the medical community regarding the correlation of female hormonal factors with the outcome of women with malignant melanoma. There have been multiple reports that women with high hormone states, such as pregnancy, had thicker tumors and/or a worse prognosis compared with a group of control women.

Amniotic fluid embolism: decreased mortality in a population-based study.

OBJECTIVE To examine the risk factors and pregnancy outcomes associated with 53 cases of amniotic fluid embolism that occurred in California during the 2-year period January 1, 1994 to December 31, 1995. METHODS Data were obtained from a computerized database that contains linked records from the vital statistics birth certificate and hospital discharge summaries of both mother and newborn. This database covered all singleton deliveries that occurred in 328 civilian acute-care hospitals in California, which represented 98% of all deliveries in California. All cases of amniotic fluid embolism were examined for other pregnancy complications. RESULTS There were 1,094,248 deliveries during that 2-year period. Fifty-three singleton gestations had the diagnosis of amniotic fluid embolism, for a population frequency of one per 20,646 deliveries. Fourteen women with amniotic fluid embolism died, for a maternal mortality rate of 26.4%. There were 35 (66%) diagnoses of disseminated intravascular coagulation (DIC), 38 (72%) diagnoses of hemorrhage, and 25 (47%) diagnoses of obstetric shock. Among the 14 women who died, the frequency of DIC (79%) and hemorrhage (71%) was not different compared with that of the survivors (62% and 72%, respectively), but obstetric shock was higher (86%, P = .02) than in survivors (33%). The average maternal length of stay for survivors was 6.5 days (range 3-27 days, median 5 days). The cesarean rate was 60% and the frequency of fetal distress was 49%. CONCLUSION In this population-based study of reported cases of amniotic fluid embolism, the maternal mortality rate (26.4%) was significantly less than previously reported and might reflect a more accurate population frequency. In addition, patients who survived and patients who died had similar pregnancy complications, suggesting that amniotic fluid embolism was present in all cases and not limited to those who died.

Birth outcomes in teenage pregnancies

OBJECTIVE To evaluate and characterize the racial/ethnic differences in obstetric outcomes of early and late teenagers in California. METHODS A data-set linking birth and death certificates with maternal and neonatal hospital discharge records in California was utilized to identify nulliparous women (11 to 29 years of age) who delivered between January 1,1992 and December 31,1997. Pregnancy outcomes of early (11-15 year) and late (16-19 year) teenagers were compared to those of a control group of women aged 20-29. RESULTS Early (n = 31 232) and late teens (n = 271 470) demonstrated greater neonatal and infant mortality and major neonatal morbidities (delivery < 37 weeks of gestation and birthweight < 2500 g) when compared to pregnancies in the older control women (n = 662 752). Ethnicity adversely affected outcome with African-Americans of all ages having worse outcomes than whites. The higher rate of adverse obstetric outcomes among the teenage pregnancies occurred despite a lower cesarean section rate and was consistent across all ethnic groups. CONCLUSIONS When compared to women aged 20-29, all teen pregnancies were associated with higher rates of poor obstetric outcomes. Other factors besides teen pregnancy appear to be responsible for poor outcomes in certain ethnic groups.

Evidence of Poorer Survival in Pregnancy-Associated Breast Cancer

OBJECTIVE: To compare stage distribution, tumor characteristics, and survival outcome in pregnancy-associated and non–pregnancy-associated breast cancer, and to evaluate pregnancy as a risk factor for mortality in breast cancer. METHODS: The California Cancer Registry (1991–1999) was linked with the California Patient Discharge Data Set to identify women with breast cancer occurring within 9 months before or 1 year after an obstetric delivery. Age-matched, non–pregnancy-associated breast cancer controls were also identified. Demographics, cancer stage, tumor size, histology, hormone receptor status, type of treatment, and survival were reviewed and compared. Predictive factors for death from breast cancer were identified using proportional hazards modeling. RESULTS: Seven hundred ninety-seven pregnancy-associated breast cancer cases were compared with 4,177 non–pregnancy-associated breast cancer controls. Pregnancy-associated breast cancer cases were significantly more likely to have more advanced stage, larger primary tumor, hormone receptor negative tumor, and mastectomy as a component of their treatment. In survival analysis, pregnancy-associated breast cancer had a higher death rate than non–pregnancy-associated breast cancer (39.2% compared with 33.4%, P=.002). In a multivariable analysis, advancing stage (2.22–10.76 times the risk of death for stages II–IV), race (African Americans had 68% increased risk of death over non-Hispanic whites), hormone receptor–negative tumors (20% increased risk of death over receptor-positive tumors), and pregnancy (14% increased risk of death over nonpregnant women) all were significant predictors of death. CONCLUSION: Pregnancy-associated breast cancer presented with more advanced disease, larger tumors, and increased percentage of hormone receptor–negative tumors. When controlled for stage, race, and hormone receptor status, pregnancy-associated breast cancer cases had a slightly higher risk of death, even when only localized-stage disease was considered. LEVEL OF EVIDENCE: II

Younger Age Is Associated with a Higher Risk of Early Periprosthetic Joint Infection and Aseptic Mechanical Failure After Total Knee Arthroplasty

BACKGROUND Although early aseptic mechanical failure after total knee arthroplasty has been reported in younger patients, it is unknown whether early revision due to periprosthetic joint infection is more or less frequent in this patient subgroup. The purpose of this study was to determine whether the incidence of early periprosthetic joint infection requiring revision knee surgery is significantly different in patients younger than fifty years of age compared with older patients following primary unilateral total knee arthroplasty. METHODS A large population-based study was conducted with use of the California Patient Discharge Database, which allows serial linkage of all discharge data from nonfederal hospitals in the state over time. Patients undergoing primary unilateral total knee arthroplasty during 2005 to 2009 were identified. Principal outcomes were partial or complete revision arthroplasty due to periprosthetic joint infection or due to aseptic mechanical failure within one year. Multivariate analysis included risk adjustment for important demographic and clinical variables. The effect of hospital total knee arthroplasty volume on the outcomes of infection and mechanical failure was analyzed with use of hierarchical modeling. RESULTS At one year, 983 (0.82%) of 120,538 primary total knee arthroplasties had undergone revision due to periprosthetic joint infection and 1385 (1.15%) had undergone revision due to aseptic mechanical failure. The cumulative incidence in patients younger than fifty years of age was 1.36% for revision due to periprosthetic joint infection and 3.49% for revision due to aseptic mechanical failure. In risk-adjusted models, the risk of periprosthetic joint infection was 1.8 times higher in patients younger than fifty years of age (odds ratio = 1.81, 95% confidence interval = 1.33 to 2.47) compared with patients sixty-five years of age or older, and the risk of aseptic mechanical failure was 4.7 times higher (odds ratio = 4.66, 95% confidence interval = 3.77 to 5.76). The rate of revision due to infection at hospitals in which a mean of more than 200 total knee arthroplasties were performed per year was lower than the expected (mean) value (p = 0.04). CONCLUSIONS Patients younger than fifty years of age had a significantly higher risk of undergoing revision due to periprosthetic joint infection or to aseptic mechanical failure at one year after primary total knee arthroplasty.

A Population-Based Comparison of the Incidence of Adverse Outcomes After Simultaneous-Bilateral and Staged-Bilateral Total Knee Arthroplasty

BACKGROUND It is unclear whether simultaneous-bilateral total knee arthroplasty is as safe as staged-bilateral arthroplasty is. We are aware of no randomized trials comparing the safety of these surgical strategies. The purpose of this study was to retrospectively compare these two strategies, with use of an intention-to-treat approach for the staged-bilateral arthroplasty cohort. METHODS We used linked hospital discharge data to compare the safety of simultaneous-bilateral and staged-bilateral knee arthroplasty procedures performed in California between 1997 and 2007. Estimates were generated to take into account patients who had planned to undergo staged-bilateral arthroplasty but never underwent the second procedure because of death, a major complication, or elective withdrawal. Hierarchical logistic regression modeling was used to adjust the comparisons for patient and hospital characteristics. The principal outcomes of interest were death, a major complication involving the cardiovascular system, and a periprosthetic knee infection or mechanical malfunction requiring revision surgery. RESULTS Records were available for 11,445 simultaneous-bilateral arthroplasty procedures and 23,715 staged-bilateral procedures. On the basis of an intermediate estimate of the number of complications that occurred after the first procedure in a staged-bilateral arthroplasty, patients who underwent simultaneous-bilateral arthroplasty had a significantly higher adjusted odds ratio (OR) of myocardial infarction (OR = 1.6, 95% confidence interval [CI] = 1.2 to 2.2) and of pulmonary embolism (OR = 1.4, 95% CI = 1.1 to 1.8), similar odds of death (OR = 1.3, 95% CI = 0.9 to 1.9) and of ischemic stroke (OR = 1.0, 95% CI = 0.6 to 1.6), and significantly lower odds of major joint infection (OR = 0.6, 95% CI = 0.5 to 0.7) and of major mechanical malfunction (OR = 0.7, 95% CI = 0.6 to 0.9) compared with patients who planned to undergo staged-bilateral arthroplasty. The unadjusted thirty-day incidence of death or a coronary event was 3.2 events per thousand patients higher after simultaneous-bilateral arthroplasty than after staged-bilateral arthroplasty, but the one-year incidence of major joint infection or major mechanical malfunction was 10.5 events per thousand lower after simultaneous-bilateral arthroplasty. CONCLUSIONS Simultaneous-bilateral total knee arthroplasty was associated with a clinically important reduction in the incidence of periprosthetic joint infection and malfunction within one year after arthroplasty, but it was associated with a moderately higher risk of an adverse cardiovascular outcome within thirty days. If patients who are at higher risk for cardiovascular complications can be identified, simultaneous-bilateral knee arthroplasty may be the preferred surgical strategy for the remaining lower-risk patients.

Hospital Variation in Readmission After Coronary Artery Bypass Surgery in California

Background—Readmissions are common after coronary artery bypass grafting (CABG) surgery and account for a significant percentage of hospital healthcare costs. Readmission rates also vary widely between hospitals, but the reasons for this variation have not been studied previously. Methods and Results—We linked 2009 California CABG clinical registry data to hospital discharge data for 2009 and 2010 to identify 30-day readmissions for all patients undergoing isolated CABG surgery. Both standard and hierarchical logistic models were developed to predict readmission risk and explore sources of hospital readmission variation. Among 11 823 patients discharged alive after isolated CABG in 2009, 1565 (13.2%) patients were readmitted within 30 days of surgery. Heart failure and postoperative infections were the most frequent reasons for readmission (15.3% and 12.9%, respectively). Multiple patient risk factors, including age, sex, and lower zip code-level median household income, were significant predictors of readmission (all adjusted odds ratios >1.0; P<0.05). The readmission rates among the 119 hospitals performing CABG varied from 0% to 26.9%. Compared with hospitals in lower quartiles for readmission, hospitals in higher quartiles had a significantly higher readmission rates due to circulatory diseases, infections, complications for surgical and medical care and digestive diseases (all P<0.05). In a hierarchical model, including several hospital characteristics, hospital-level variables did not predict readmission risk (all P>0.05, with an intraclass correlation of 0.004 for hospitals). Conclusions—California hospitals performing CABG surgery vary widely in 30-day readmission rates. Patient demographic and clinical risk factors, rather than measured hospital characteristics, accounted for most of the observed hospital-level variation in CABG readmissions.