Jacob E. Simmering

MRSA in Conventional and Alternative Retail Pork Products

In order to examine the prevalence of Staphylococcus aureus on retail pork, three hundred ninety-five pork samples were collected from a total of 36 stores in Iowa, Minnesota, and New Jersey. S. aureus was isolated from 256 samples (64.8%, 95% confidence interval [CI] 59.9%–69.5%). S. aureus was isolated from 67.3% (202/300) of conventional pork samples and from 56.8% (54/95) of alternative pork samples (labeled “raised without antibiotics” or “raised without antibiotic growth promotants”). Two hundred and thirty samples (58.2%, 95% CI 53.2%–63.1%) were found to carry methicillin-sensitive S. aureus (MSSA). MSSA was isolated from 61.0% (183/300) of conventional samples and from 49.5% (47/95) of alternative samples. Twenty-six pork samples (6.6%, 95% CI 4.3%–9.5%) carried methicillin-resistant S. aureus (MRSA). No statistically significant differences were observed for the prevalence of S. aureus in general, or MSSA or MRSA specifically, when comparing pork products from conventionally raised swine and swine raised without antibiotics, a finding that contrasts with a prior study from the Netherlands examining both conventional and “biologic” meat products. In our study spa types associated with “livestock-associated” ST398 (t034, t011) were found in 26.9% of the MRSA isolates, while 46.2% were spa types t002 and t008—common human types of MRSA that also have been found in live swine. The study represents the largest sampling of raw meat products for MRSA contamination to date in the U.S. MRSA prevalence on pork products was higher than in previous U.S.-conducted studies, although similar to that in Canadian studies.

Hospital Transfer Network Structure as a Risk Factor for Clostridium difficile Infection

OBJECTIVE To determine the effect of interhospital patient sharing via transfers on the rate of Clostridium difficile infections in a hospital. DESIGN Retrospective cohort. METHODS Using data from the Healthcare Cost and Utilization Project California State Inpatient Database, 2005-2011, we identified 2,752,639 transfers. We then constructed a series of networks detailing the connections formed by hospitals. We computed 2 measures of connectivity, indegree and weighted indegree, measuring the number of hospitals from which transfers into a hospital arrive, and the total number of incoming transfers, respectively. Next, we estimated a multivariate model of C. difficile infection cases using the log-transformed network measures as well as covariates for hospital fixed effects, log median length of stay, log fraction of patients aged 65 or older, and quarter and year indicators as predictors. RESULTS We found an increase of 1 in the log indegree was associated with a 4.8% increase in incidence of C. difficile infection (95% CI, 2.3%-7.4%) and an increase of 1 in log weighted indegree was associated with a 3.3% increase in C. difficile infection incidence (1.5%-5.2%). Moreover, including measures of connectivity in our models greatly improved their fit. CONCLUSIONS Our results suggest infection control is not under the exclusive control of a given hospital but is also influenced by the connections and number of connections that hospitals have with other hospitals.

Web search query volume as a measure of pharmaceutical utilization and changes in prescribing patterns

BACKGROUND Monitoring prescription drug utilization is important for both drug safety and drug marketing purposes. However, access to utilization data is often expensive, limited and not timely. OBJECTIVES To demonstrate and validate the use of web search engine queries as a method for timely monitoring of drug utilization and changes in prescribing behaviors. METHODS Drug utilization time series were obtained from the Medical Expenditure Panel Survey and normalized search volume was obtained from Google Trends. Correlation between the series was estimated using a cross-correlation function. Changes in the search volume following knowledge events were detected using a cumulative sums changepoint method. RESULTS Search volume tracks closely with the utilization rates of several seasonal prescription drugs. Additionally, search volume exhibits changes following known major knowledge events, such as the publication of new information. CONCLUSIONS Search volume provides a first order approximation to pharmaceutical utilization in the community and can be used to detect changes in prescribing behavior.

Identifying Patients With COPD at High Risk of Readmission

Background: Readmission within 30 days of a COPD hospitalization is a common measure of performance for COPD care. However, most studies of COPD readmission risk have been constrained to a single data source, private payer claims, or Medicare claims data, making it difficult to generalize results from these studies to other populations. The purpose of this study was to examine the risk for readmission within 30 days from time of discharge in patients with COPD using the Healthcare Cost and Utilization Project (HCUP) State Inpatient Database for California for the years 2005-2011. This statewide dataset allows us to consider all readmissions for COPD regardless of age or payer status. Methods: The total dataset included 28,265,070 visits among 17,918,374 patients over 480 hospitals. We identified patients with a hospitalization, a primary diagnosis related to COPD, age 40 or older, and discharged alive. We found 286,313 hospitalizations that matched this definition and included information on covariates such as comorbidities, age, and insurance status. To characterize the joint associations of these covariates with readmission within 30 days, we used a generalized linear model. Results: Patients aged 40-64 are more likely to be readmitted to the hospital within 30 days of a COPD-related hospitalization than patients 65 and older. This effect persists after adjustment for patient severity, comorbidities, payer, and demographics. Our model featured an interaction of age with insurance type. We found that younger patients (aged 40-64) on public insurance have the highest readmission rates: 14.77% for Medicare and 16.27% for Medicaid. However, younger patients with private insurance have the lowest readmission rates at 8.25%. Additional significant covariates included whether or not the patient left against medical advice, and diagnoses of congestive heart failure and diabetes. In addition, we found that although admissions for COPD were highest in the winter, this is not true for COPD readmissions, which peak in summer. Also, inpatient mortality for patients admitted for COPD decreased from approximately 3% to 1.25% over the study period. Conclusion: Our results demonstrate that many of the risk factors for readmission may be dependent on the data source used. Furthermore, many of the strongest predictors are clearly related to the patients themselves. This observation may help explain why prior programs to reduce readmissions have had limited success.

Are Well-Child Visits a Risk Factor for Subsequent Influenza-Like Illness Visits?

OBJECTIVE To determine whether well-child visits are a risk factor for subsequent influenza-like illness (ILI) visits within a childs family. DESIGN Retrospective cohort. METHODS Using data from the Medical Expenditure Panel Survey from the years 1996-2008, we identified 84,595 families. For each family, we determined those weeks in which a well-child visit or an ILI visit occurred. We identified 23,776 well-child-visit weeks and 97,250 ILI-visit weeks. We fitted a logistic regression model, where the binary dependent variable indicated an ILI clinic visit in a particular week. Independent variables included binary indicators to denote a well-child visit in the concurrent week or one of the previous 2 weeks, the occurrence of the ILI visit during the influenza season, and the presence of children in the family in each of the age groups 0-3, 4-7, and 8-17 years. Socioeconomic variables were also included. We also estimated the overall cost of well-child-exam-related ILI using data from 2008. RESULTS We found that an ILI office visit by a family member was positively associated with a well-child visit in the same or one of the previous 2 weeks (odds ratio, 1.54). This additional risk translates to potentially 778,974 excess cases of ILI per year in the United States, with a cost of

The Increase in Hospitalizations for Urinary Tract Infections and the Associated Costs in the United States, 1998–2011

500 million annually. CONCLUSIONS Our results should encourage ambulatory clinics to strictly enforce infection control recommendations. In addition, clinics could consider time-shifting of well-child visits so as not to coincide with the peak of the influenza season.

The Seasonal Variability of Surgical Site Infections in Knee and Hip Arthroplasty

Abstract Background Outpatient therapies for urinary tract infections (UTIs) are becoming limited due to antimicrobial resistance. The purpose of this paper is to report how the incidence of hospitalizations for UTIs have varied over time in both men and women and across age groups. We also explore how the severity for UTI hospitalizations has changed and describe the seasonality of UTI hospitalizations. Methods Using the Nationwide Inpatient Sample, we compute a time-series of UTI incidence and subdivide the series by age and sex. We fit a collection of time-series models to explore how the trend and seasonal intensity varies by age and sex. We modeled changes in severity using regression with available confounders. Results In 2011, there were approximately 400000 hospitalizations for UTIs with an estimated cost of

Weather-Dependent Risk for Legionnaires' Disease, United States

2.8 billion. Incidence increased by 52% between 1998 and 2011. The rate of increase was larger among both women and older patients. We found that the seasonal intensity (summer peaks and winter troughs) increased over time among women while decreasing among men. For both men and women, seasonality decreased with advancing age. Relative to controls and adjusted for demographics, we found that costs among UTI patients grew more slowly, patients left the hospital earlier, and patients had lower odds of death. Conclusions Incidence of UTI hospitalization is increasing and is seasonal, peaking in the summer. However, the severity of UTI admissions seems to be decreasing, indicating that patients previously treated as outpatients may now be admitted to the hospital due to increasing antimicrobial resistance.

The effect of automated text messaging and goal setting on pedometer adherence and physical activity in patients with diabetes: A randomized controlled trial

BACKGROUND Surgical site infections (SSIs) after total knee (TKA) and total hip (THA) arthroplasty are devastating to patients and costly to healthcare systems. The purpose of this study is to investigate the seasonality of TKA and THA SSIs at a national level. METHODS All data were extracted from the National Readmission Database for 2013 and 2014. Patients were included if they had undergone TKA or THA. We modeled the odds of having a primary diagnosis of SSI as a function of discharge date by month, payer status, hospital size, and various patient co-morbidities. SSI status was defined as patients who were readmitted to the hospital with a primary diagnosis of SSI within 30 days of their arthroplasty procedure. RESULTS There were 760,283 procedures (TKA 424,104, THA 336,179) in our sample. Our models indicate that SSI risk was highest for patients discharged from their surgery in June and lowest for December discharges. For TKA, the odds of a 30-day readmission for SSI were 30.5% higher at the peak compared to the nadir time (95% confidence interval [CI] 20-42). For THA, the seasonal increase in SSI was 19% (95% CI 9-30). Compared to Medicare, patients with Medicaid as the primary payer had a 49% higher odds of 30-day SSI after TKA (95% CI 32-68). CONCLUSION SSIs following TKA and THA are seasonal peaking in summer months. Payer status was also a significant risk factor for SSIs. Future studies should investigate potential factors that could relate to the associations demonstrated in this study.

Warmer weather as a risk factor for hospitalisations due to urinary tract infections

Using the Nationwide Inpatient Sample and US weather data, we estimated the probability of community-acquired pneumonia (CAP) being diagnosed as Legionnaires’ disease (LD). LD risk increases when weather is warm and humid. With warm weather, we found a dose-response relationship between relative humidity and the odds for LD. When the mean temperature was 60°–80°F with high humidity (>80.0%), the odds for CAP being diagnosed with LD were 3.1 times higher than with lower levels of humidity (<50.0%). Thus, in some regions (e.g., the Southwest), LD is rarely the cause of hospitalizations. In other regions and seasons (e.g., the mid-Atlantic in summer), LD is much more common. Thus, suspicion for LD should increase when weather is warm and humid. However, when weather is cold, dry, or extremely hot, empirically treating all CAP patients for LD might contribute to excessive antimicrobial drug use at a population level.