Sheila R. Weiss

Using seasonal variations in asthma hospitalizations in children to predict hospitalization frequency

Asthma hospitalization rates have increased in the United States since 1980. The exposure risk of many environmental factors, which contribute to respiratory disease, vary throughout the year. The objective of this study was to investigate the seasonal variation of pediatric asthma hospitalizations and predict hospitalization frequency. This was a longitudinal analysis of all pediatric asthma hospitalizations in the state of Maryland by age, gender, race, and residence using non-confidential discharge data sets from 1986 to 1999. Of the 631,422 pediatric hospitalizations in the state of Maryland during the years 1986-1999, 45,924 (7%) had a primary admission diagnosis of asthma. Frequency of hospitalization for asthma was lowest in the summer in all age groups, and highest in the fall. Seasonal variation in severe asthma episodes was least striking in children aged 15-18. This was in contrast to non-asthma admissions, which were highest in winter in preschool children, but relatively flat in school- and teenaged children. Using neural network modeling, weekly asthma hospitalizations could be predicted with an R2 between 0.71 and 0.8. Temporal trends in asthma hospitalizations were seen in each age group, gender, race, and location. The seasonal variability in asthma hospitalizations suggests that acute asthma is influenced by variables beyond socioeconomic factors and adherence to medical regimens. Strategies to combat exacerbations of asthma should take into consideration seasonal effects on a population. In addition, temporal trends examined over many years can be used to predict frequency of severe asthma episodes in a population.

Temporal dynamics of emergency department and hospital admissions of pediatric asthmatics

Asthma is a chronic disease that can result in exacerbations leading to urgent care in emergency departments (EDs) and hospitals. We examined seasonal and temporal trends in pediatric asthma ED (1997-1999) and hospital (1986-1999) admission data so as to identify periods of increased risk of urgent care by age group, gender, and race. All pediatric ED and hospital admission data for Maryland residents occurring within the state of Maryland were evaluated. Distinct peaks in pediatric ED and hospital asthma admissions occurred each year during the winter-spring and autumn seasons. Although the number and timing of these peaks were consistent across age and racial groups, the magnitude of the peaks differed by age and race. The same number, timing, and relative magnitude of the major peaks in asthma admissions occurred statewide, implying that the variables affecting these seasonal patterns of acute asthma exacerbations occur statewide. Similar gross seasonal trends are observed worldwide. Although several environmental, infectious, and psychosocial factors have been linked with increases in asthma exacerbations among children, thus far they have not explained these seasonal patterns of admissions. The striking temporal patterns of pediatric asthma admissions within Maryland, as described here, provide valuable information in the search for causes.

Cancer recurrences and second primary cancers after use of antihistamines or antidepressants

Reports in the scientific literature have described accelerated tumor growth in association with antidepressant and antihistamine exposure in experimental rodent cancer models. This study was designed to determine whether exposure to prescription antidepressants or antihistamines is associated with tumor growth in humans.

Patterns of erythropoiesis-stimulating agent use among Medicare beneficiaries with myelodysplastic syndromes and consistency with clinical guidelines

Erythropoiesis-stimulating agents (ESA) are used commonly to reduce symptomatic anemia in patients with myelodysplastic syndromes (MDS). We assessed population-based patterns of ESA use relative to treatment guidelines using data from the Surveillance, Epidemiology, and End Results (SEER) registries, with linked Medicare claims providing detailed treatment data from 2001 through 2005. The study found widespread use (62%) of ESA in Medicare beneficiaries with MDS. Similar ESA use rates regardless of risk status, low frequency (45%) of serum erythropoietin determination prior to ESA initiation, and high prevalence (60.4%) of short-duration ESA episodes suggest clinically important discrepancies between actual practice and guideline-recommended therapy.

Relationships between pediatric asthma and socioeconomic/urban variables in Baltimore, Maryland

Spatial relationships between clinical data for pediatric asthmatics (hospital and emergency department utilization rates), and socioeconomic and urban characteristics in Baltimore City were analyzed with the aim of identifying factors that contribute to increased asthma rates. Socioeconomic variables and urban characteristics derived from satellite data explained 95% of the spatial variation in hospital rates. The proportion of families headed by a single female was the most important variable accounting for 89% of the spatial variation. Evidence suggests that the high rates of hospital admissions and emergency department (ED) visits may partially be due to the difficulty of single parents with limited resources managing their childs asthma condition properly. This knowledge can be used for education towards mitigating ED and hospital events in Baltimore City.

Looking Beyond Urban/Rural Differences: Emergency Department Utilization by Asthmatic Children

Asthma causes pediatric morbidity throughout the US with substantial regional variability. Emergency department (ED) utilization data were studied to determine if geographic variability of pediatric asthma cases exists within a state. Records for non-neonatal Maryland children less than 18 years of age seen and discharged from Maryland EDs from April 1997 through March 2001 were analyzed. While Baltimore City had the highest rates of asthma visits, adjusted odds ratios identified the wealthiest suburban county to have a higher risk of an asthma ED visit. Children from rural counties, for the most part, had fewer ED asthma visits than children from urban and suburban counties.

Clinical Correlates of Estrogen Replacement Therapy Use and Duration of Use among Medicaid Recipients

Estrogen replacement therapy (ERT) is used not only for the short-term control of menopausal symptoms but long-term for disease prevention. This study examined the influence of selected clinical conditions on the use of ERT and the duration of ERT use among women enrolled in a state Medicaid program. We identified 60,531 women, aged >/=45 years, who were enrolled in Maryland Medicaid continuously for at least 2 of 3 years. ERT use was determined through prescription claims submitted for reimbursement. The presence or risk of selected clinical conditions (e.g., osteoporosis, heart disease, estrogen-sensitive cancers) was determined by screening Medicaid claims files for related diagnoses, procedures, or prescription claims. Multiple logistic regression was used to model ERT use, and proportional hazards regression was used to model duration of use. Fourteen percent of these women filled an ERT prescription, with use varying by age, race, and place of residence. Oral dosage forms were the most popular (80.8%), followed by vaginal cream or ring (22.2%), and transdermal patch (7.3%). In adjusted models, osteoporosis, heart disease, hypertension, hyperlipidemia, diabetes, ovarian cancer, and thromboembolic disease were positively associated and dementia and breast cancer were negatively associated with ERT use. None of these medical conditions predicted the duration of estrogen therapy. Use of ERT was very low among these women despite coverage of prescription medications, and the presence of clinical indications had no influence on the length of therapy among these women despite known benefits for long-term preventive therapy.

Pharmacist’s Guide to Pregnancy Registry Studies

OBJECTIVE To introduce the concept and design characteristics of pregnancy registries and to discuss opportunities for pharmacist involvement. DATA SOURCES Previous and ongoing pregnancy registry studies that assess the safety of pharmaceutical agents in pregnant women were identified from the medical literature, Internet, abstracts from professional meetings, and personal communications. DATA EXTRACTION The development and use of the pregnancy registry study for evaluating drug safety is described. Then, to illustrate the application of scientific principles to this unique study design, examples are given from previous and ongoing pregnancy registry studies. DATA SYNTHESIS Pregnancy registry studies are increasingly used to assess the safety of drugs and other therapeutic agents during pregnancy. In a pregnancy registry, women who took the study drug while pregnant are identified soon after that exposure and followed until their pregnancy ends and its outcome is determined. Information is compiled from hundreds or thousands of pregnancies and used to make a safety assessment. CONCLUSION Pharmacists can explain pregnancy registries to pregnant women and encourage enrollment. Also, pharmacists can use information derived from these studies to help patients and health care providers manage inadvertent drug exposures and optimize pharmaceutical therapy during pregnancy.

Predicting paediatric asthma hospital admissions and ED visits

Historical data for hospital admissions and Emergency Department (ED) visits in Baltimore City contain information concerning temporal patterns of paediatric asthma service utilisation (e.g. number of peaks and troughs, timing, relative magnitudes, steepness of rise and fall of the endemic cycles, etc.). This historical information can be captured by linear and neural network models to accurately predict the level of asthma admissions for the next few days or one week. Using 14 years of data, the best neural network models explained over 80% of the variations in admissions data with root mean square errors of 5–7 admissions per week. Models developed to predict asthma admissions can aid in identifying future peak periods of asthma admissions, alerting and educating individual asthmatic patients to periods of increased risk, and mitigating asthma events that lead to ED and/or hospital admissions. It is believed that these modelling techniques using historical data can be applied to any city or region with similar accuracies.

Variations in erythropoiesis-stimulating agent administration in transfusion-dependent myelodysplastic syndromes impact response

INTRODUCTION Erythropoiesis-stimulating agents (ESAs) reduce red blood cell (RBC) transfusions in approximately 40% of patients with myelodysplastic syndrome (MDS) in clinical trials. We studied the association of timing of ESA initiation, agent (epoetin alfa, darbepoetin) and number of weeks of ESA use with response in MDS patients in routine practice. METHODS Patients diagnosed with MDS from 2001 to 2005 were identified in the Surveillance Epidemiology and End Results-Medicare linked database. The study cohort consisted of patients with new-onset transfusion dependence (TD). All patients received an ESA at least once during the study period, which began the week that criteria for TD were met and continued until transfusion independence (TI). Kaplan-Meier statistics and Cox Proportional Hazard models were used to assess relationships between time to ESA initiation, agent and number of weeks of ESA use and TI attainment. RESULTS Of 610 TD patients treated with ESAs, 210 (34.4%) achieved TI. Median time from ESA initiation to TI was 13 weeks. Shorter time from TD to ESA initiation and use of darbepoetin were associated with higher probability of achieving TI. The probability of achieving TI decreased beyond 8 weeks of treatment, and was very low beyond 16 weeks (8-15 weeks: HR=0.64, 16-31 weeks: HR=0.25, 32+ weeks HR=0.10). CONCLUSIONS In this observational, population-based study, variations in ESA administration impacted response in transfusion-dependent MDS patients, with higher response rates with early administration and use of darbepoetin, and low response likelihood in non-responders beyond 16 weeks of therapy.