We also explored the association between the number of antihypertensives and systolic, diastolic, and pulse pressure. After 15 months, 41% of participants met blood pressure targets. CKD was not associated with control (adjusted odds ratio: 1.04; 95% CI: 0.93 to 1.15). However, CKD was associated with higher odds of use of ≥3 medications among nondiabetic subjects (odds ratio: 1.46; 95% CI: 1.25 to 1.71) and diabetic subjects (odds ratio: 1.40; 95% CI: 1.17 to 1.66). A significant interaction was observed between CKD and the number of antihypertensives as determinants of diastolic and pulse pressures. Among non-CKD participants, a greater number of antihypertensives (0 compared with 4) was associated with wider pulse pressure ({Delta}5.2 mm Hg; P<0.001), mainly because of higher systolic pressures ({Delta}3.6 mm Hg; P=0.001).

Among participants with CKD, although greater numbers of antihypertensives were associated with even wider pulse pressures ({Delta}8.3 mm Hg; P<0.001), this was primarily because of lower diastolic pressures ({Delta}4.8 mm Hg; P<0.01). Among participants with CKD, greater use of antihypertensives was associated with lower diastolic pressures. Given recent evidence suggesting adverse effects of diastolic hypotension, these results suggest potential risks in patients with CKD from aggressive attempts to control systolic blood pressure.

Background: In 2002, the Accreditation Council on Graduate Medical Education enacted regulations, effective 1 July 2003, that limited work hours for all residency programs in the United States.

Objective: To determine whether work-hour regulations were associated with changes in mortality in hospitalized patients.

Design: Comparison of mortality rates in high-risk teaching service patients hospitalized before and after July 2003, with nonteaching service patients used as a control group.

Setting: 551 U.S. community hospitals included in the Healthcare Cost and Utilization Project's Nationwide Inpatient Survey between January 2001 and December 2004.

Patients: 1,511,945 adult patients admitted for 20 medical and 15 surgical diagnoses.

Measurement: Inpatient mortality.

Results: In 1,268,738 medical patients examined, the regulations were associated with a 0.25% reduction in the absolute mortality rate (P = 0.043) and a 3.75% reduction in the relative risk for death. In subgroup analyses, particularly large improvements in mortality were observed among patients admitted for infectious diseases (change, -0.66%; P = 0.007) and in medical patients older than 80 years of age (change, -0.71%; P = 0.005). By contrast, in 243 207 surgical patients, regulations were not associated with statistically significant changes (change, 0.13%; P = 0.54).

Limitations: Teaching status was assigned according to hospital characteristics because direct information on each patient's provider was not available. Results reflect changes associated with the sum of regulations, not specifically with caps on work hours.

Conclusions: The work-hour regulations were associated with decreased short-term mortality among high-risk medical patients in teaching hospitals but were not associated with statistically significant changes among surgical patients in teaching hospitals.

Background: Carotid endarterectomy (CEA) has been shown to decrease future ischemic stroke risk in selected patients. However, clinical trials did not examine the risk-benefit ratio for nonwhites, who have a greater ischemic stroke risk than whites. In general, few studies have examined the effects of race on CEA use and complications, and data on race and CEA readmission are lacking.

Methods: This study used administrative data for patients discharged from California hospitals between January 1 and December 31, 2000. Selection criteria of cases included: ICD-9 principal procedure code 38.12, principal diagnostic code 433 and diagnosis-related group 5. There were 8,080 white and 1196 nonwhite patients (228 blacks, 643 Hispanics, 325 Asians/Pacific Islanders) identified that underwent an elective and isolated CEA. For both groups, CEA rates were compared. Logistic regression was used to examine the independent effects of race on in-hospital death and stroke, as well as CEA readmission.

Results: Rates of CEA use were more than three times greater for whites than nonwhites, although nonwhites were more likely to have symptomatic disease. For all patients, the complication rate was 1.9%. However, the odds of in-hospital death and stroke were greater for nonwhites than whites, but after adjustment for patient and hospital factors, these differences were only significant for stroke (OR = 1.7, P = 0.013). For both outcomes, the final models had good predictive accuracy. Overall, CEA readmission risk was 7%, and no significant racial differences were observed (P = 0.110).

Conclusions: The data suggest that CEA is performed safely in California. However, nonwhites had lower rates of initial CEA use but higher rates of in-hospital death and stroke than whites. Racial differences in stroke risk persisted after adjustment for patient and hospital factors. Finally, this study found that despite significant racial disparities in initial CEA use, whites and nonwhites were similar in their CEA readmission rates. These findings may suggest that screening initiatives are lacking for nonwhites, which may increase their risk for poorer outcomes.

Background: There has been a large increase in both the number of neonatal intensive care units (NICUs) in community hospitals and the complexity of the cases treated in these units. We examined differences in neonatal mortality among infants with very low birth weight (below 1500 g) among NICUs with various levels of care and different volumes of very-low-birth-weight infants.

Methods: We linked birth certificates, hospital discharge abstracts (including interhospital transfers), and fetal and infant death certificates to assess neonatal mortality rates among 48,237 very-low-birth-weight infants who were born in California hospitals between 1991 and 2000.

Results: Mortality rates among very-low-birth-weight infants varied according to both the volume of patients and the level of care at the delivery hospital. The effect of volume also varied according to the level of care. As compared with a high level of care and a high volume of very-low-birth-weight infants (more than 100 per year), lower levels of care and lower volumes (except for those of two small groups of hospitals) were associated with significantly higher odds ratios for death, ranging from 1.19 (95% confidence interval [CI], 1.04 to 1.37) to 2.72 (95% CI, 2.37 to 3.12). Less than one quarter of very-low-birth-weight deliveries occurred in facilities with NICUs that offered a high level of care and had a high volume, but 92% of very-low-birth-weight deliveries occurred in urban areas with more than 100 such deliveries.

Conclusions: Mortality among very-low-birth-weight infants was lowest for deliveries that occurred in hospitals with NICUs that had both a high level of care and a high volume of such patients. Our results suggest that increased use of such facilities might reduce mortality among very-low-birth-weight infants.

Purpose: Recent studies and anecdotal evidence suggest that patient safety may be compromised on weekends. Our objective was to determine whether rates of complications in hospitals are higher on weekends than on weekdays.

Methods: We examined records from 4,967,114 admissions to acute care hospitals in 3 states and analyzed complication rates using the Patient Safety Indicators. We selected 8 indicators that could be assigned to a single day: complications of anesthesia, retained foreign bodies, postoperative hemorrhage, accidental cuts and lacerations during procedures, birth trauma, obstetric trauma during vaginal deliveries with and without instrumentation, and obstetric trauma during cesarean delivery. Odds ratios (ORs) comparing weekends versus weekdays were adjusted for demographics, type of admission, and admission route. In a subgroup analysis of surgical complications, we restricted the population to patients who underwent cardiac or vascular procedures.

Results: Four of the 8 complications occurred more frequently on weekends: postoperative hemorrhage (OR 1.07, 95% confidence interval [CI], 1.01-1.14), newborn trauma (OR 1.06, 95% CI, 1.03-1.10), vaginal deliveries without instrumentation (OR 1.03, 95% CI, 1.02-1.04), and obstetric trauma during cesarean sections (OR 1.36, 95% CI, 1.29-1.44). Complications related to anesthesia occurred less frequently on weekends (OR 0.86). Among patients undergoing vascular procedures, surgical complications occurred more frequently on weekends (OR 1.46, 95% CI, 1.16-1.85).

Conclusions: Rates of complications are marginally higher on weekends than on weekdays for some surgical and newborn complications, but more significantly for obstetric trauma and for surgical complications involving patients undergoing vascular procedures. Hospitals should work toward increasing the robustness of safeguards on weekends.

Context: Hospitals are under pressure to increase revenue and lower costs, and at the same time, they face dramatic variation in clinical demand.

Objective: We sought to determine the relationship between peak hospital workload and rates of adverse events (AEs).

Methods: A random sample of 24,676 adult patients discharged from the medical/surgical services at 4 US hospitals (2 urban and 2 suburban teaching hospitals) from October 2000 to September 2001 were screened using administrative data, leaving 6841 cases to be reviewed for the presence of AEs. Daily workload for each hospital was characterized by volume, throughput (admissions and discharges), intensity (aggregate DRG weight), and staffing (patient-to-nurse ratios). For volume, we calculated an "enhanced" occupancy rate that accounted for same-day bed occupancy by more than 1 patient. We used Poisson regressions to predict the likelihood of an AE, with control for workload and individual patient complexity, and the effects of clustering.

Results: One urban teaching hospital had enhanced occupancy rates more than 100% for much of the year. At that hospital, admissions and patients per nurse were significantly related to the likelihood of an AE (P 0.05); occupancy rate, discharges, and DRG-weighted census were significant at P 0.10. For example, a 0.1% increase in the patient-to-nurse ratio led to a 28% increase in the AE rate. Results at the other 3 hospitals varied and were mainly non significant.

Conclusions: Hospitals that operate at or over capacity may experience heightened rates of patient safety events and might consider re-engineering the structures of care to respond better during periods of high stress.

Objective: To describe the development of an instrument for assessing workforce perceptions of hospital safety culture and to assess its reliability and validity.

Data Sources/Study Setting: Primary data collected between March 2004 and May 2005. Personnel from 105 U.S. hospitals completed a 38-item paper and pencil survey. We received 21,496 completed questionnaires, representing a 51 percent response rate.

Study Design: Based on review of existing safety climate surveys, we developed a list of key topics pertinent to maintaining a culture of safety in high-reliability organizations. We developed a draft questionnaire to address these topics and pilot tested it in four preliminary studies of hospital personnel. We modified the questionnaire based on experience and respondent feedback, and distributed the revised version to 42,249 hospital workers.

Data Collection: We randomly divided respondents into derivation and validation samples. We applied exploratory factor analysis to responses in the derivation sample. We used those results to create scales in the validation sample, which we subjected to multitrait analysis (MTA).

Principal Findings: We identified nine constructs, three organizational factors, two unit factors, three individual factors, and one additional factor. Constructs demonstrated substantial convergent and discriminant validity in the MTA. Cronbach's  coefficients ranged from 0.50 to 0.89.

Conclusions: It is possible to measure key salient features of hospital safety climate using a valid and reliable 38-item survey and appropriate hospital sample sizes. This instrument may be used in further studies to better understand the impact of safety climate on patient safety outcomes.

Six cases of coagulase-negative staphylococcal mediastinitis were identified in the latter half of 1999. A new preoperative cleansing solution was suspected by hospital staff to be a factor in the outbreak. We evaluated this possible risk factor along with other known and suspected surgical site infection risk factors in this case-control study.