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Biomedical subjects

Patrick G Arbogast

Publications and source records attributed to Patrick G Arbogast.

At least 19 recordsLinked to original sources
PubMed2008

Impact of proximity to comprehensive sickle cell center on utilization of healthcare services among children with sickle cell disease.

BACKGROUND: The impact of comprehensive care on utilization of healthcare services by children with sickle cell disease (SCD) has not been fully evaluated. We compared the medical care utilization and mortality in children less than 20 years of age with SCD in four regions in the state of Tennessee with and without a comprehensive sickle cell center (CSCC). METHODS: Rates of hospitalizations, outpatient and emergency department (ED) visits, and deaths were measured in a cohort of children aged <20 years with SCD, enrolled in TennCare, from January 1995 to December 2002. TennCare data linked to Tennessee vital records were used to define the population and identify the outcomes. The patients were classified into one of four regions based on their residential address on the day of their hospitalization or outpatient visit. RESULTS: The cohort consisted of 1,214 children with 6,393 person-years of follow-up. Fifty-six percent of patients resided in the region with the CSCC. This region had the highest overall rates of hospitalization for all children (P < 0.001), while ED and outpatient visits were higher in other areas. The death rates ranged from 1.8 to 4.3 per 1,000 person-years in the four regions and did not represent statistically significant differences. CONCLUSION: No clear pattern of improved utilization of medical care services were identified in relation to proximity of residence to a CSCC. This cohort was not large enough to detect small differences in death rates. In addition, other outcomes that incorporate quality of life measures may be more sensitive to differences in medical care.

Adolescent↗
PubMed2007

Beta-blocker exposure is associated with improved survival after severe traumatic brain injury.

BACKGROUND: Beta-blocker use in elective noncardiac surgery has been associated with a reduction in mortality and cardiovascular complications. Traumatic brain injury (TBI) is often associated with a hyperadrenergic state. We hypothesized that adrenergic blockade would confer improved survival among TBI patients. METHODS: Retrospective review of the Trauma Registry of the American College of Surgeons database at a Level I trauma center was conducted. All trauma patients admitted from January 2004 to March 2005 with head Abbreviated Injury Scale score of 3 or greater were evaluated. Patients with length of stay <4 or >30 days were excluded. Beta-blocker exposure was defined as receiving beta-blockers for 2 or more consecutive days. RESULTS: In all, 420 patients met inclusion criteria: 174 patients exposed to beta-blockers [BB(+)] and 246 not exposed [BB(-)]. Mean age in BB(+) group was 50 years and 36 years in BB(-) group (p < 0.001). Mean Injury Severity Score was 33.6 for BB(+) group and 30.8 for BB(-) group (p = 0.01). Predicted survival (by Trauma and Injury Severity Score) for BB(+) group was 59.1% compared with 70.3% for BB(-) group (p < 0.001). Observed mortality for BB(+) group was 5.1%, 10.8% for BB(-) group (p = 0.036). Adjusted incidence rate ratio of mortality among those exposed to beta-blockers compared with those not exposed was 0.29 (95% confidence interval). CONCLUSIONS: Beta-blocker exposure was associated with a significant reduction in mortality in patients with severe TBI. This reduction in mortality is even more impressive, considering that the BB(+) group was older, more severely injured, and had lower predicted survival.

Adrenergic beta-Antagonists↗
PubMed2006

Major congenital malformations after first-trimester exposure to ACE inhibitors.

BACKGROUND: Use of angiotensin-converting-enzyme (ACE) inhibitors during the second and third trimesters of pregnancy is contraindicated because of their association with an increased risk of fetopathy. In contrast, first-trimester use of ACE inhibitors has not been linked to adverse fetal outcomes. We conducted a study to assess the association between exposure to ACE inhibitors during the first trimester of pregnancy only and the risk of congenital malformations. METHODS: We studied a cohort of 29,507 infants enrolled in Tennessee Medicaid and born between 1985 and 2000 for whom there was no evidence of maternal diabetes. We identified 209 infants with exposure to ACE inhibitors in the first trimester alone, 202 infants with exposure to other antihypertensive medications in the first trimester alone, and 29,096 infants with no exposure to antihypertensive drugs at any time during gestation. Major congenital malformations were identified from linked vital records and hospitalization claims during the first year of life and confirmed by review of medical records. RESULTS: Infants with only first-trimester exposure to ACE inhibitors had an increased risk of major congenital malformations (risk ratio, 2.71; 95 percent confidence interval, 1.72 to 4.27) as compared with infants who had no exposure to antihypertensive medications. In contrast, fetal exposure to other antihypertensive medications during only the first trimester did not confer an increased risk (risk ratio, 0.66; 95 percent confidence interval, 0.25 to 1.75). Infants exposed to ACE inhibitors were at increased risk for malformations of the cardiovascular system (risk ratio, 3.72; 95 percent confidence interval, 1.89 to 7.30) and the central nervous system (risk ratio, 4.39; 95 percent confidence interval, 1.37 to 14.02). CONCLUSIONS: Exposure to ACE inhibitors during the first trimester cannot be considered safe and should be avoided.

Abnormalities, Drug-Induced↗
PubMed2006

Improved compliance with quality measures at hospital discharge with a computerized physician order entry system.

BACKGROUND: Most measures used to assess the quality of care of hospitalized patients with congestive heart failure (CHF) and acute myocardial infarction (AMI) involve discharge medications and instructions. Implementation of disease-specific computerized physician order entry (CPOE) discharge tools may improve compliance with these measures. METHODS: We studied 286 versus 290 AMI and 595 versus 656 CHF discharges in the pre-CPOE (July 2001 to June 2002) and CPOE (October 2002 to September 2003) periods, respectively. Compliance with chosen quality measures (aspirin and beta-blocker use for AMI, ejection fraction determination and discharge instructions for CHF, and angiotensin-converting enzyme inhibitor use, and smoking cessation counseling for both) was assessed. RESULTS: Compliance with recommended discharge medications was high at baseline and did not change significantly. Smoking cessation counseling (43% vs 1% for CHF and 62% vs 21% for AMI) and discharge instructions for CHF (56% vs 3%) improved significantly in the CPOE period. Overall, 63% of patients with CHF and AMI in the CPOE period were discharged using the tools. Compliance with prescription of recommended medications was 100% among eligible patients when CPOE was used; however, this improvement was due entirely to better documentation of contraindications in the CPOE period. The actual proportion of patients who received discharge prescriptions between the pre-CPOE and CPOE periods did not change: beta-blockers (85% vs 84%), angiotensin-converting enzyme inhibitor for AMI (77% vs 76%), and for CHF (56% vs 61%). However, nonmedication measures significantly improved when CPOE was used. CONCLUSIONS: Implementation of a CPOE discharge tool improved compliance with selected quality measures in patients with AMI and CHF. Effective methods of rapid implementation and acceptance of these tools by providers require further study.

Cardiology Service, Hospital↗
PubMed2005

Performance of floating absolute risks.

A recent investigation of hormone replacement therapy and breast cancer risk used a method called "floating absolute risks" (FARs) to compute confidence intervals for relative hazards. This method has been used in other medical studies and has received controversy. This controversy stems from the correct implementation of this method. However, there has been no direct comparison of the FAR method, as it is sometimes incorrectly applied and reported, with the conventional approach for computing confidence intervals from proportional hazards regression. In this paper, the author reports simulation results comparing these two methods and demonstrates that the FAR method, when applied incorrectly, can produce confidence intervals that are substantially too narrow.

Confidence Intervals↗
PubMed2005

Asthma as a risk factor for invasive pneumococcal disease.

BACKGROUND: The risk of invasive pneumococcal disease among persons with asthma is unknown. METHODS: We conducted a nested case-control study to examine the association between asthma and invasive pneumococcal disease. The study population included persons 2 to 49 years of age who were enrolled in Tennessee's Medicaid program (TennCare) for more than one year during the study period (1995 through 2002) and who resided in counties participating in a prospective laboratory-based program of surveillance for invasive pneumococcal disease. For each subject with invasive pneumococcal disease, 10 age-matched controls without invasive pneumococcal disease were randomly selected from the same population. TennCare files were queried to identify the presence of coexisting conditions that confer a high risk of pneumococcal disease. For the purpose of our study, asthma was defined by documentation of one or more inpatient or emergency-department diagnoses of asthma, two outpatient diagnoses, or the use of asthma-related medications. High-risk asthma was defined as asthma requiring admission to a hospital or a visit to an emergency department, the use of rescue therapy or long-term use of oral corticosteroids, or the dispensing of three or more prescriptions for beta-agonists within the year before enrollment in the study. RESULTS: A total of 635 persons with invasive pneumococcal disease and 6350 controls were identified, of whom 114 (18.0 percent) and 516 (8.1 percent), respectively, had asthma. Persons with asthma had an increased risk of invasive pneumococcal disease (adjusted odds ratio, 2.4; 95 percent confidence interval, 1.9 to 3.1) as compared with controls. Among those without coexisting conditions, the annual incidence of invasive pneumococcal disease was 4.2 episodes per 10,000 persons with high-risk asthma and 2.3 episodes per 10,000 persons with low-risk asthma, as compared with 1.2 episodes per 10,000 persons without asthma. CONCLUSIONS: Asthma is an independent risk factor for invasive pneumococcal disease. The risk among persons with asthma was at least double that among controls.

Adolescent↗
PubMed2005

Prescribing of contraindicated protease inhibitor and statin combinations among HIV-infected persons.

HIV-1 protease inhibitors (PIs) contribute to hyperlipidemia in persons treated for HIV infection. There are potential drug-drug interactions between PIs and some statins, which are drugs frequently used to treat hyperlipidemia. We performed a retrospective cohort study using the TennCare program to determine prescribing rates of contraindicated combinations of PIs and statins in HIV-infected persons in Tennessee and to assess changes in prescribing after publication of treatment guidelines. Computerized files identified adult patients with antiretroviral prescriptions and overlapping prescriptions for PIs and statins from January 1, 1996 through June 30, 2002. A subset of these combinations was defined as contraindicated based on published guidelines. Changes in patterns of prescribing after publication of preliminary treatment guidelines were examined using a mixed-effects logistic regression model. There were 3448 persons who received PIs during the study period. The proportion of PI users receiving statins increased from 3.5% during January 1996 through December 2000 to 7.9% during January 2001 through June 2002 (P < 0.001). Contraindicated PI-statin use decreased from 42.0% of combinations to 20.8% during the same periods (P < 0.001). Use of PIs and statins has increased in the adult TennCare population. Contraindicated combinations have decreased but remain unacceptably high.

Adolescent↗
PubMed2005

Model-checking techniques for stratified case-control studies.

We present graphical and numerical methods for assessing the adequacy of the logistic regression model for stratified case-control data. The proposed methods are derived from the cumulative sum of residuals over the covariate or linear predictor. Under the assumed model, the cumulative residual process converges weakly to a zero-mean Gaussian process whose distribution can be approximated via Monte Carlo simulation. The observed cumulative residual pattern can then be compared both visually and analytically to a number of simulated realizations from the approximate null distribution. These comparisons enable one to examine the functional form of each covariate, the logistic link function as well as the overall model adequacy. Simulation studies demonstrate that the proposed methods perform well in practical settings. Illustration with an oesophageal cancer study is provided.

Adult↗
PubMed2005

Medical care utilization and mortality in sickle cell disease: a population-based study.

The purpose of this study was to evaluate the pattern of medical care utilization and mortality in children and adults with sickle cell disease (SCD) in the state of Tennessee. Rates of hospitalization, emergency department visits, and deaths were measured in a cohort of adults and children with SCD enrolled in TennCare, Tennessee's Medicaid managed health care program, from January 1995 to December 2002. TennCare data linked to Tennessee vital records were used to define the population and identify the outcomes. For children less than 5 years of age, the mortality rate was similar to that of other black Tennessee children (P = 0.71). Among children, the death rate was highest in 10-19 years of age and was 8-fold higher than Tennessee's race- and age-specific rate. Among 20- to 49-year-old patients with SCD, mortality was significantly higher in males than in females (P < 0.001). As compared to the black population without SCD in TennCare, patients with SCD had 7-30 times higher rate of hospitalization and 2-6 times higher rates of emergency department visits (P < 0.001). The death rate in adolescents and young adults with SCD continues to be much higher than population-specific rates. Interventions to prevent morbidity and mortality related to SCD are urgently needed.

Adolescent↗
PubMed2005

Seasonality of invasive pneumococcal disease: temporal relation to documented influenza and respiratory syncytial viral circulation.

BACKGROUND: Seasonal fluctuation in the incidence of invasive pneumococcal disease has been attributed to winter virus exposure (e.g., influenza and respiratory syncytial virus [RSV]). Evidence of a direct correlation of invasive pneumococcal disease with laboratory-confirmed virus seasons, however, is limited. Using two prospective surveillance networks, the temporal relation between invasive pneumococcal disease and isolation of circulating winter viruses was explored. METHODS: Episodes of invasive pneumococcal disease in five Tennessee counties were collected prospectively from January 1995 through June 2002. Virus seasons were defined using prospective laboratory-based surveillance. Correlation between weekly identification of invasive pneumococcal disease and laboratory isolation of RSV and influenza, as well as comparisons of the frequencies of invasive pneumococcal disease episodes during viral and nonviral seasons were determined. RESULTS: A total of 4147 invasive pneumococcal disease episodes were identified. Weekly frequency of invasive pneumococcal disease correlated directly with the weekly frequency of isolation of RSV (r = 0.56, P <0.001) and influenza (r= 0.40, P <0.001). The average weekly frequency of invasive pneumococcal disease during RSV and influenza seasons was higher than during the nonviral seasons (P <0.001 for each year). CONCLUSION: Weekly episodes of invasive pneumococcal disease correlated temporally with laboratory-confirmed weekly isolation of RSV and influenza, and the incidence of invasive pneumococcal disease was increased when these viruses were circulating in the community.

Adolescent↗
PubMed2005

Gaps in enrollment from a Medicaid managed care program: effects on emergency department visits and hospitalizations for children with asthma.

BACKGROUND: For high-risk children with asthma enrolled in Medicaid, loss of Medicaid coverage is a potential threat to access to quality asthma care. OBJECTIVE: We sought to quantify the effect of gaps in enrollment on emergency department visits and hospitalizations for children with asthma in TennCare, Tennessee's managed care program for Medicaid-eligible and uninsured children. METHODS: Children with asthma were identified from a research database of files maintained by the state. Gaps in enrollment in the state insurance program were measured between 1998 and 2002. Children with gaps were compared with children without gaps with respect to emergency department visits and hospitalizations for asthma, respiratory illnesses, croup, and other diagnoses. RESULTS: Among children who met study definitions of asthma, 2373 experienced a gap in enrollment during the study period (10.4%). The rate of hospitalizations and emergency department visits for children with gaps (7402/10,000 person years) was significantly lower than the rate of study events for children with no gaps (9230/10,000 person years) (adjusted incidence rate ratio 0.88; 95% confidence interval 0.81-0.96). The rate of hospitalizations for asthma and other respiratory conditions was not different between the 2 groups; however, there was a significantly lower rate of hospitalizations for other reasons for children with gaps (adjusted incidence rate ratio 0.59; 95% confidence interval 0.41-0.86). CONCLUSIONS: Children with asthma who had gaps in a Medicaid managed care insurance program had no increase in asthma related emergency department visits and hospitalizations. Children who had gaps did have fewer nonrespiratory emergency department visits and hospitalizations than their non-gap counterparts. Further study is needed to explore the reasons for this unexpected finding.

Adolescent↗
PubMed2005

Resident work hour limits and patient safety.

OBJECTIVE: This study evaluates the effect of resident physician work hour limits on surgical patient safety. BACKGROUND: Resident work hour limits have been enforced in New York State since 1998 and nationwide from 2003. A primary assumption of these limits is that these changes will improve patient safety. We examined effects of this policy in New York on standardized surgical Patient Safety Indicators (PSIs). METHODS: An interrupted time series analysis was performed using 1995 to 2001 Nationwide Inpatient Sample data. The intervention studied was resident work hour limit enforcement in New York teaching hospitals. PSIs included rates of accidental puncture or laceration (APL), postoperative pulmonary embolus or deep venous thrombosis (PEDVT), foreign body left during procedure (FB), iatrogenic pneumothorax (PTX), and postoperative wound dehiscence (WD). PSI trends were compared pre- versus postintervention in New York teaching hospitals and in 2 control groups: New York nonteaching hospitals and California teaching hospitals. RESULTS: A mean of 2.6 million New York discharges per year were analyzed with cumulative events of 33,756 (APL), 36,970 (PEDVT), 1,447 (FB), 10,727 (PTX), and 2,520 (WD). Increased rates over time (expressed per 1000 discharges each quarter) were observed in both APL (0.15, 95% confidence interval, 0.09-0.20, P<0.05) and PEDVT (0.43, 95% confidence interval, 0.03-0.83, P<0.05) after policy enforcement in New York teaching hospitals. No changes were observed in either control group for these events or New York teaching hospital rates of FB, PTX, or WD. CONCLUSIONS: Resident work hour limits in New York teaching hospitals were not associated with improvements in surgical patient safety measures, with worsening trends observed in APL and PEDVT corresponding with enforcement.

Adult↗
PubMed2005

Prescriptions for chronic high-dose cyclooxygenase-2 inhibitors are often inappropriate and potentially dangerous.

OBJECTIVE: To describe the use of coxibs outside of licensed indications and recommended dosing ranges including rofecoxib 50 mg, valdecoxib 20 to 40 mg, and celecoxib 400 mg. DESIGN: Cross-sectional study of coxib utilization in 2002 and 2003 and retrospective cohort analysis of new users. PARTICIPANTS: Patients with known age and sex enrolled in Tennessee's Medicaid program. MEASUREMENTS: The prevalence of coxib use by dose and duration, and the proportion of persons initially prescribed a high-dose coxib and indications for such use. RESULTS: The estimated daily prevalence of nonaspirin prescription nonsteroidal anti-inflammatory drugs (NSAIDs) was 8.7% in 2002 to 2003 (45.7% coxibs). NSAID use peaked at age 65 to 74 with a prevalence of 19.8% (56.3% coxibs). Doses above the recommended daily dose for osteoarthritis accounted for 33.2% (95% confidence intervals [CIs] 32.4%, 33.9%) of celecoxib use, 14.9% (95% CI 14.4%, 15.5%) of rofecoxib use, and 52.2% (95% CI 50.6%, 53.8%) of valdecoxib use. Most of these prescriptions were for a month's supply. For new coxib users, 13.5% were given a month's supply for the highest dose category, and 28% refilled their prescriptions within 7 days of the end of the original prescription. Of these new chronic high-dose users, 17.2% had ischemic heart disease and 7.1% had heart failure. CONCLUSIONS: A substantial portion of coxib prescriptions were for a month's supply at doses above those recommended for most chronic indications. New users were also prescribed high doses despite evidence for cardiovascular comorbidity. These prescribing patterns at doses outside licensed indications are both inappropriate and potentially dangerous.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2004

Reduction in high rates of antibiotic-nonsusceptible invasive pneumococcal disease in tennessee after introduction of the pneumococcal conjugate vaccine.

BACKGROUND: Invasive pneumococcal disease (IPD) is a burgeoning problem, with rates of antibiotic-nonsusceptible IPD, in particular, increasing during the past decade. One measure to combat IPD is vaccination with the recently introduced 7-valent pneumococcal conjugate vaccine (PCV). METHODS: To evaluate the effects of the introduction of PCV in 2000 on the epidemiology of antibiotic-nonsusceptible IPD, a database of IPD cases from January 1995 through December 2002 identified through active surveillance in 5 Tennessee counties was examined. For each case, clinical data were collected, and antibiotic susceptibility testing and serotyping were performed on available isolates. RESULTS: Among children younger than 2 years, IPD rates peaked at 235 cases per 100,000 in 1999 before decreasing, after PCV licensure, to 46 cases per 100,000 in 2002 (P<.001). The proportion of penicillin-nonsusceptible IPD isolates from this age group declined from 59.8% in 1999 to 30.4% in 2002 (P<.01). After 2001, similar decreases in IPD rates and in the proportion of antibiotic-nonsusceptible isolates recovered were seen among persons aged 2 years and older (P<.01). Rates of IPD due to PCV-associated serotypes declined after PCV introduction in all age groups (P<.001), whereas the rate of IPD due to nonvaccine serotypes increased among persons aged 2 years and older. CONCLUSIONS: In the 2 years since licensure, widespread PCV vaccination of children has resulted in dramatic declines in the proportion of antibiotic-nonsusceptible isolates in Tennessee. PCV vaccination of children also appears to be a highly effective method for reducing the burden of IPD in adults.

Anti-Bacterial Agents↗
PubMed2004

Outpatient utilization of angiotensin-converting enzyme inhibitors among heart failure patients after hospital discharge.

OBJECTIVES: This study was designed to assess outpatient angiotensin-converting enzyme inhibitor (ACEI) use after heart failure (HF) hospitalization. BACKGROUND: Assuring therapy with ACEIs at discharge after HF hospitalization is a key Medicare quality measure. The benefits of such quality improvement attempts will be limited if therapy is not continued long-term. METHODS: To assess the factors associated with filling an ACEI prescription in the 30 days postdischarge and the proportion of patients who filled such prescriptions subsequently up to 365 days postdischarge, we studied 219 patients with depressed ejection fraction (EF) specifically and 960 HF patients in general. RESULTS: Sixty-seven percent of patients with depressed EF and 55% of the total cohort were discharged with ACEIs. Overall 81.2%/77.1% (depressed EF/total cohort) of survivors discharged with ACEIs had filled a prescription by 30 days postdischarge; only 66.3%/63.3% were current users at 365 days. In contrast, for patients with no discharge order for ACEIs, only 12.7%/12.0% (depressed EF/total cohort) had filled such a prescription by 30 days and 12.5%/18.8% were current users at 365 days postdischarge. Patients with a discharge order for ACEIs were more likely to fill a prescription within 30 days postdischarge (hazard ratio 10.93, 95% confidence interval 5.28, 22.61, for patients with depressed EF). CONCLUSIONS: For patients with HF who are discharged while taking ACEIs, there is a significant decline in use after discharge. Patients not discharged with ACEIs are unlikely to be started as outpatients. Quality improvement efforts therefore need to be focused on both discharge planning and outpatient care.

Aftercare↗
PubMed2004

New users of antipsychotic medications among children enrolled in TennCare.

BACKGROUND: The use of antipsychotic medications in children and adolescents for indications other than psychosis or Tourette syndrome is controversial. Newer atypical antipsychotics with profiles of adverse effects that differ from those of traditional antipsychotics may lead providers to prescribe antipsychotics more frequently than in the past for behavioral indications not strongly supported by clinical study. OBJECTIVE: To identify population-based new use of antipsychotics among patients aged 2 to 18 years. DESIGN: Retrospective cohort study, January 1, 1996, through December 31, 2001. SETTING: Tennessee's managed care program for Medicaid enrollees and the uninsured (TennCare). MAIN OUTCOME MEASURES: New use of antipsychotic medications and indications for use by the child's diagnosis, adjusted for age, sex, race, county of residence, enrollment category, and income. RESULTS: The proportion of TennCare children who were new users of antipsychotics, adjusted for demographic characteristics, nearly doubled from 23/10 000 in 1996 to 45/10 000 in 2001 (adjusted incidence rate ratio, 1.98; 95% confidence interval, 1.82-2.16). In 1996, 6.8% of new users received an atypical antipsychotic; by 2001, this had increased to 95.9%. New use for attention-deficit/hyperactivity disorder and affective disorders increased 2.5-fold. New use of antipsychotics for schizophrenia, acute psychotic reaction, Tourette syndrome, and mental retardation or autism remained relatively constant. Secular trends of increasing use were most pronounced for those aged 6 to 12 years (93% increase) and 13 to 18 years (116% increase), although use among preschool children increased 61% during the study period. CONCLUSION: The proportion of TennCare children who became new users of antipsychotics nearly doubled from 1996 to 2001, with a substantial increase in use of antipsychotics for attention-deficit/hyperactivity disorder, conduct disorder, and affective disorders.

Adolescent↗