Diurnal temperature variation and the implications for diagnosis and infectious disease screening: a population-based study

OBJECTIVES

Fevers have been used as a marker of disease for hundreds of years and are frequently used for disease screening. However, body temperature varies over the course of a day and across individual characteristics; such variation may limit the detection of febrile episodes complicating the diagnostic process. Our objective was to describe individual variation in diurnal temperature patterns during episodes of febrile activity using millions of recorded temperatures and evaluate the probability of recording a fever by sex and for different age groups.

METHODS

We use timestamped deidentified temperature readings from thermometers across the US to construct illness episodes where continuous periods of activity in a single user included a febrile reading. We model the mean temperature recorded and probability of registering a fever across the course of a day using sinusoidal regression models while accounting for user age and sex. We then estimate the probability of recording a fever by time of day for children, working-age adults, and older adults.

RESULTS

We find wide variation in body temperatures over the course of a day and across individual characteristics. The diurnal temperature pattern differed between men and women, and average temperatures declined for older age groups. The likelihood of detecting a fever varied widely by the time of day and by an individual's age or sex.

CONCLUSIONS

Time of day and demographics should be considered when using body temperatures for diagnostic or screening purposes. Our results demonstrate the importance of follow-up thermometry readings if infectious diseases are suspected.

Cystic Fibrosis Carrier States Are Associated With More Severe Cases of Bronchiectasis

Background

People with cystic fibrosis (CF) are at increased risk for bronchiectasis, and several reports suggest that CF carriers may also be at higher risk for developing bronchiectasis. The purpose of this study was to determine if CF carriers are at risk for more severe courses or complications of bronchiectasis.

Methods

Using MarketScan data (2001-2021), we built a cohort consisting of 105 CF carriers with bronchiectasis and 300 083 controls with bronchiectasis but without a CF carrier diagnosis. We evaluated if CF carriers were more likely to be hospitalized for bronchiectasis. In addition, we examined if CF carriers were more likely to be infected with Pseudomonas aeruginosa or nontuberculous mycobacteria (NTM) or to have filled more antibiotic prescriptions. We considered regression models for incident and rate outcomes that controlled for age, sex, smoking status, and comorbidities.

Results

The odds of hospitalization were almost 2.4 times higher (95% CI, 1.116-5.255) for CF carriers with bronchiectasis when compared with non-CF carriers with bronchiectasis. The estimated odds of being diagnosed with a Pseudomonas infection for CF carriers vs noncarriers was about 4.2 times higher (95% CI, 2.417-7.551) and 5.4 times higher (95% CI, 3.398-8.804) for being diagnosed with NTM. The rate of distinct antibiotic fill dates was estimated to be 2 times higher for carriers as compared with controls (95% CI, 1.735-2.333), and the rate ratio for the total number of days of antibiotics supplied was estimated as 2.8 (95% CI, 2.290-3.442).

Conclusions

CF carriers with bronchiectasis required more hospitalizations and more frequent administration of antibiotics as compared with noncarriers. Given that CF carriers were also more likely to be diagnosed with Pseudomonas and NTM infections, CF carriers with bronchiectasis may have a phenotype more resembling CF-related bronchiectasis than non-CF bronchiectasis.

Association between household opioid prescriptions and risk for overdose among family members not prescribed opioids

BACKGROUND

Prescription opioids have contributed to the rise in opioid-related overdoses and deaths. The presence of opioids within households may increase the risk of overdose among family members who were not prescribed an opioid themselves. Larger quantities of opioids may further increase risk.

OBJECTIVES

To determine the risk of opioid overdose among individuals who were not prescribed an opioid but were exposed to opioids prescribed to other family members in the household, and evaluate the risk in relation to the total morphine milligram equivalents (MMEs) present in the household.

METHODS

We conducted a cohort study using a large database of commercial insurance claims from 2001 to 2021. For inclusion in the cohort, we identified individuals not prescribed an opioid in the prior 90 days from households with two or more family members, and determined the total MMEs prescribed to other family members. Individuals were stratified into monthly enrollment strata defined by household opioid exposure and other confounders. A generalized linear model was used to estimate incidence rate ratios (IRRs) for overdose.

RESULTS

Overall, the incidence of overdose among enrollees in households where a family member was prescribed an opioid was 1.73 (95% confidence interval [CI]: 1.67-1.78) times greater than households without opioid prescriptions. The risk of overdose increased continuously with the level of potential MMEs in the household from an IRR of 1.23 (95% CI: 1.16-1.32) for 1-100 MMEs to 4.67 (95% CI: 4.18-5.22) for >12,000 MMEs. The risk of overdose associated with household opioid exposure was greatest for ages 1-2 years (IRR: 3.46 [95% CI: 2.98-4.01]) and 3-5 years (IRR: 3.31 [95% CI: 2.75-3.99]).

CONCLUSIONS

The presence of opioids in a household significantly increases the risk of overdose among other family members who were not prescribed an opioid. Higher levels of MMEs, either in terms of opioid strength or quantity, were associated with increased levels of risk. Risk estimates may reflect accidental poisonings among younger family members.

Gap junction mediated bioelectric coordination is required for slow muscle development, organization, and function

Bioelectrical signaling, intercellular communication facilitated by membrane potential and electrochemical coupling, is emerging as a key regulator of animal development. Gap junction (GJ) channels can mediate bioelectric signaling by creating a fast, direct pathway between cells for the movement of ions and other small molecules. In vertebrates, GJ channels are formed by a highly conserved transmembrane protein family called the Connexins. The connexin gene family is large and complex, presenting a challenge in identifying the specific Connexins that create channels within developing and mature tissues. Using the embryonic zebrafish neuromuscular system as a model, we identify a connexin conserved across vertebrate lineages, gjd4, which encodes the Cx46.8 protein, that mediates bioelectric signaling required for appropriate slow muscle development and function. Through a combination of mutant analysis and in vivo imaging we show that gjd4/Cx46.8 creates GJ channels specifically in developing slow muscle cells. Using genetics, pharmacology, and calcium imaging we find that spinal cord generated neural activity is transmitted to developing slow muscle cells and synchronized activity spreads via gjd4/Cx46.8 GJ channels. Finally, we show that bioelectrical signal propagation within the developing neuromuscular system is required for appropriate myofiber organization, and that disruption leads to defects in behavior. Our work reveals the molecular basis for GJ communication among developing muscle cells and reveals how perturbations to bioelectric signaling in the neuromuscular system_may contribute to developmental myopathies. Moreover, this work underscores a critical motif of signal propagation between organ systems and highlights the pivotal role played by GJ communication in coordinating bioelectric signaling during development.

Radiosurgery Dose Reduction for Brain Metastases on Immunotherapy (RADREMI): One-Year Safety and Efficacy Outcomes from a Multicenter Phase I Trial

PURPOSE/OBJECTIVE(S)

The combination of immunotherapy and single-fraction stereotactic radiosurgery (SRS) for treatment of metastatic brain disease has yielded symptomatic radiation necrosis rates as high as 20% (PMID: 29327059). Consequently, the Radiosurgery Dose Reduction for Brain Metastases on Immunotherapy (RADREMI) multicenter phase I trial (registered at clinicaltrials.gov, NCT04047602) was created to address whether reduced-dose SRS can improve morbidity without compromising efficacy. In this report we present our one-year findings.

MATERIALS/METHODS

Eligibility for RADREMI enrollment required brain metastases patients with: a) Histologically-confirmed primary malignancy, b) Receipt of immunotherapy within 30 days of SRS, c) 1-10 MRI-visible brain metastases, d) Estimated median survival of at least 6 months (via disease-specific graded prognostic assessment), and e) No history of whole brain radiation therapy. Reduced-dose SRS utilized 18 Gy for lesions 0-2 cm, 14 Gy for lesions 2.1-3 cm, and 12 Gy for lesions 3.1-4 cm. Symptomatic radiation necrosis was defined as imaging findings consistent with radiation necrosis combined with clinical symptoms requiring steroid administration and/or operative intervention. Local control was defined by Response Assessment in Neuro-Oncology (RANO) criteria.

RESULTS

From December 18, 2019 to June 30, 2022, 54 lesions in 17 patients were treated on RADREMI with at least one-year of follow-up. One-year local control occurred in 52 of 54 lesions and in 15 of 17 patients, yielding control rates of 96% per lesion and 88% per patient. Radiographic radiation necrosis occurred in 2 of 54 lesions (4%). No symptomatic radiation necrosis occurred.

CONCLUSION

Our findings of concurrent immunotherapy + reduced-dose SRS at one-year post-treatment revealed excellent local control (96%) with no symptomatic radiation necrosis, and minimal radiographic radiation necrosis. These results attest to the durability of the safety and efficacy of reduced-dose SRS with immunotherapy for metastatic brain disease.

Influence of Radiation Fractionation on Immune Repertoire Diversity in Solid Tumor Patients

PURPOSE/OBJECTIVE(S)

Radiation (RT)-induced lymphopenia (RIL) occurs in up to 75% of patients undergoing RT and is associated with worse tumor control and survival across a spectrum of solid tumors. Patients undergoing hypofractionated RT are at lower risk of RIL compared with patients treated with more prolonged RT courses. However, it is unknown whether immune repertoire diversity is similarly affected by fractionation scheme in patients undergoing RT. This prospective study analyzed RT-induced changes in immune repertoire diversity in patients treated with conventionally (CFRT) vs hypofractionated RT (HFRT).

MATERIALS/METHODS

RNA-based T and B cell receptor sequencing was performed on peripheral lymphocytes collected prospectively before RT and within 4 weeks of the last RT fraction from 23 patients (18 men, 5 women, median age 67 y) with primary solid tumors undergoing CFRT (≤3 Gy/day x ≥10 days, n = 13) or HFRT (≥5 Gy/day x ≤5 days, n = 10). Absolute lymphocyte counts (ALC; cells/μL) were obtained from clinical laboratory data. The number of unique CDR3 receptors (uCDR3) and Shannon entropy were used to monitor changes in T (TCR Vβ) and B (BCR IgH) receptor diversity.

RESULTS

ALC decreased after RT in 90% (20/22) of patients (mean pre-RT ALC 1830 vs 1040 post-RT, p <0.001). Mean % ALC loss was greater in CFRT vs HFRT patients (44.3 vs. 35.2%). After RT, entropy in IgH and Vβ decreased in 18/23 (78%) and 17/23 (74%) patients, respectively; uCDR3 in IgH and Vβ decreased in 14/23 (61%) and 15/23 (65%). Among patients with concordant decreases in ALC and uCDR3, a moderate correlation between magnitude of ALC loss and uCDR3 levels in the T-cell receptor Vβ was observed (r = 0.64, p = 0.02). For both receptor species studied (IgH and Vβ), HFRT patients were more likely to have an increase in either entropy or uCDR3 in the face of decreased ALC (36 vs 15%, X2 p = 0.03). Furthermore, while decreases in entropy were observed among the CFRT patients for both IgH (median entropy 10.4 vs 9.4, p = 0.06) and Vβ (9.7 vs 8.1, p = 0.02), entropy did not significantly change following RT in the HFRT patients (IgH 10.6 vs 10.4, p = 0.74 and Vβ 10.9 vs 10.8, p = 0.24).

CONCLUSION

RT-induced changes in immune repertoire diversity are variably reflected in the peripheral ALC. Both HFRT and CFRT depleted circulating lymphocytes, but patients undergoing HFRT were more likely to experience increases in T and B cell diversity metrics despite lymphopenia. It is therefore possible that relative sparing of repertoire diversity among patients undergoing HFRT could increase the likelihood of tumor antigen recognition by peripheral blood lymphocytes. As immune repertoire diversity is associated with the likelihood of response to immunotherapy, these findings also have implications for RT-immunotherapy combinations. Further study is required to understand the relationship between RT exposure to circulating lymphocyte populations and immune repertoire diversity.

The incidence, duration, risk factors, and age-based variation of missed opportunities to diagnose pertussis: A population-based cohort study

OBJECTIVE

To estimate the incidence, duration and risk factors for diagnostic delays associated with pertussis.

DESIGN

We used longitudinal retrospective insurance claims from the Marketscan Commercial Claims and Encounters, Medicare Supplemental (2001-2020), and Multi-State Medicaid (2014-2018) databases.

SETTING

Inpatient, emergency department, and outpatient visits.

PATIENTS

The study included patients diagnosed with pertussis (International Classification of Diseases [ICD] codes) and receipt of macrolide antibiotic treatment.

METHODS

We estimated the number of visits with pertussis-related symptoms before diagnosis beyond that expected in the absence of diagnostic delays. Using a bootstrapping approach, we estimated the number of visits representing a delay, the number of missed diagnostic opportunities per patient, and the duration of delays. Results were stratified by age groups. We also used a logistic regression model to evaluate potential factors associated with delay.

RESULTS

We identified 20,828 patients meeting inclusion criteria. On average, patients had almost 2 missed opportunities prior to diagnosis, and delay duration was 12 days. Across age groups, the percentage of patients experiencing a delay ranged from 29.7% to 37.6%. The duration of delays increased considerably with age from an average of 5.6 days for patients aged <2 years to 13.8 days for patients aged ≥18 years. Factors associated with increased risk of delays included emergency department visits, telehealth visits, and recent prescriptions for antibiotics not effective against pertussis.

CONCLUSIONS

Diagnostic delays for pertussis are frequent. More work is needed to decrease diagnostic delays, especially among adults. Earlier case identification may play an important role in the response to outbreaks by facilitating treatment, isolation, and improved contact tracing.

Comparison of Different Antibiotics and the Risk for Community-Associated Clostridioides difficile Infection: A Case-Control Study

Background

Antibiotics are the greatest risk factor for Clostridioides difficile infection (CDI). Risk for CDI varies across antibiotic types and classes. Optimal prescribing and stewardship recommendations require comparisons of risk across antibiotics. However, many prior studies rely on aggregated antibiotic categories or are underpowered to detect significant differences across antibiotic types. Using a large database of real-world data, we evaluate community-associated CDI risk across individual antibiotic types.

Methods

We conducted a matched case-control study using a large database of insurance claims capturing longitudinal health care encounters and medications. Case patients with community-associated CDI were matched to 5 control patients by age, sex, and enrollment period. Antibiotics prescribed within 30 days before the CDI diagnosis along with other risk factors, including comorbidities, health care exposures, and gastric acid suppression were considered. Conditional logistic regression and a Bayesian analysis were used to compare risk across individual antibiotics. A sensitivity analysis of antibiotic exposure windows between 30 and 180 days was conducted.

Results

We identified 159 404 cases and 797 020 controls. Antibiotics with the greatest risk for CDI included clindamycin and later-generation cephalosporins, and those with the lowest risk included minocycline and doxycycline. We were able to differentiate and order individual antibiotics in terms of their relative level of associated risk for CDI. Risk estimates varied considerably with different exposure windows considered.

Conclusions

We found wide variation in CDI risk within and between classes of antibiotics. These findings ordering the level of associated risk across antibiotics can help inform tradeoffs in antibiotic prescribing decisions and stewardship efforts.

Using Thermal Imaging to Track Cellulitis

Background

Cellulitis is a common soft tissue infection and a major cause of morbidity. The diagnosis is based almost exclusively on clinical history and physical exam. To improve the diagnosis of cellulitis, we used a thermal camera to track how skin temperature of the affected area changed during a hospital stay for patients with cellulitis.

Methods

We recruited 120 patients admitted with a diagnosis of cellulitis. Daily thermal images of the affected limb were taken. Temperature intensity and area were analyzed from the images. Highest daily body temperature and antibiotics administered were also collected.We estimated a longitudinal linear mixed-effects model with a random intercept for the affected body area. All observations on a given day were included, and we used an integer time indicator indexed to the initial day (ie, t = 1 for the first day the patient was observed, etc.). We then analyzed the effect of this time trend on both severity (ie, normalized temperature) and scale (ie, area of skin with elevated temperature).

Results

We analyzed thermal images from the 41 patients with a confirmed case of cellulitis who had at least 3 days of photos. For each day that the patient was observed, the severity decreased by 1.63 (95% CI, -13.45 to 10.32) units on average, and the scale decreased by 0.63 (95% CI, -1.08 to -0.17) points on average. Also, patients' body temperatures decreased by 0.28°F each day (95% CI, -0.40 to -0.17).

Conclusions

Thermal imaging could be used to help diagnose cellulitis and track clinical progress.

A comprehensive framework to estimate the frequency, duration, and risk factors for diagnostic delays using bootstrapping-based simulation methods

BACKGROUND

The incidence of diagnostic delays is unknown for many diseases and specific healthcare settings. Many existing methods to identify diagnostic delays are resource intensive or difficult to apply to different diseases or settings. Administrative and other real-world data sources may offer the ability to better identify and study diagnostic delays for a range of diseases.

METHODS

We propose a comprehensive framework to estimate the frequency of missed diagnostic opportunities for a given disease using real-world longitudinal data sources. We provide a conceptual model of the disease-diagnostic, data-generating process. We then propose a bootstrapping method to estimate measures of the frequency of missed diagnostic opportunities and duration of delays. This approach identifies diagnostic opportunities based on signs and symptoms occurring prior to an initial diagnosis, while accounting for expected patterns of healthcare that may appear as coincidental symptoms. Three different bootstrapping algorithms are described along with estimation procedures to implement the resampling. Finally, we apply our approach to the diseases of tuberculosis, acute myocardial infarction, and stroke to estimate the frequency and duration of diagnostic delays for these diseases.

RESULTS

Using the IBM MarketScan Research databases from 2001 to 2017, we identified 2,073 cases of tuberculosis, 359,625 cases of AMI, and 367,768 cases of stroke. Depending on the simulation approach that was used, we estimated that 6.9-8.3% of patients with stroke, 16.0-21.3% of patients with AMI and 63.9-82.3% of patients with tuberculosis experienced a missed diagnostic opportunity. Similarly, we estimated that, on average, diagnostic delays lasted 6.7-7.6 days for stroke, 6.7-8.2 days for AMI, and 34.3-44.5 days for tuberculosis. Estimates for each of these measures was consistent with prior literature; however, specific estimates varied across the different simulation algorithms considered.

CONCLUSIONS

Our approach can be easily applied to study diagnostic delays using longitudinal administrative data sources. Moreover, this general approach can be customized to fit a range of diseases to account for specific clinical characteristics of a given disease. We summarize how the choice of simulation algorithm may impact the resulting estimates and provide guidance on the statistical considerations for applying our approach to future studies.

A clinically-guided unsupervised clustering approach to recommend symptoms of disease associated with diagnostic opportunities

OBJECTIVES

A first step in studying diagnostic delays is to select the signs, symptoms and alternative diseases that represent missed diagnostic opportunities. Because this step is labor intensive requiring exhaustive literature reviews, we developed machine learning approaches to mine administrative data sources and recommend conditions for consideration. We propose a methodological approach to find diagnostic codes that exhibit known patterns of diagnostic delays and apply this to the diseases of tuberculosis and appendicitis.

METHODS

We used the IBM MarketScan Research Databases, and consider the initial symptoms of cough before tuberculosis and abdominal pain before appendicitis. We analyze diagnosis codes during healthcare visits before the index diagnosis, and use k-means clustering to recommend conditions that exhibit similar trends to the initial symptoms provided. We evaluate the clinical plausibility of the recommended conditions and the corresponding number of possible diagnostic delays based on these diseases.

RESULTS

For both diseases of interest, the clustering approach suggested a large number of clinically-plausible conditions to consider (e.g., fever, hemoptysis, and pneumonia before tuberculosis). The recommended conditions had a high degree of precision in terms of clinical plausibility: >70% for tuberculosis and >90% for appendicitis. Including these additional clinically-plausible conditions resulted in more than twice the number of possible diagnostic delays identified.

CONCLUSIONS

Our approach can mine administrative datasets to detect patterns of diagnostic delay and help investigators avoid under-identifying potential missed diagnostic opportunities. In addition, the methods we describe can be used to discover less-common presentations of diseases that are frequently misdiagnosed.

Understanding the Prodromal Period of Necrotizing Soft Tissue Infections of the Genitalia (Fournier's Gangrene) and the Incidence, Duration, and Risk Factors Associated With Potential Missed Opportunities for an Earlier Diagnosis: A Population-based Longitudinal Study

PURPOSE

The purpose of this paper was to investigate patterns of health care utilization leading up to diagnosis of necrotizing soft tissue infections of the genitalia and to identify risk factors associated with potential diagnostic delay.

MATERIALS AND METHODS

IBM MarketScan Research Databases (2001-2020) were used to identify index cases of necrotizing soft tissue infections of the genitalia. We identified health care visits for symptomatically similar diagnoses (eg, penile swelling, cellulitis) that occurred prior to necrotizing soft tissue infections of the genitalia diagnosis. A change-point analysis identified the window before diagnosis where diagnostic opportunities first appeared. A simulation model estimated the likelihood symptomatically similar diagnosis visits represented a missed opportunity for earlier diagnosis. Patient and provider characteristics were evaluated for their associations with delay.

RESULTS

We identified 8,098 patients with necrotizing soft tissue infections of the genitalia, in which 4,032 (50%) had a symptomatically similar diagnosis visit in the 21-day diagnostic window, most commonly for "non-infectious urologic abnormalities" (eg, genital swelling; 64%): 46% received antibiotics; 16% saw a urologist. Models estimated that 5,096 of the symptomatically similar diagnosis visits (63%) represented diagnostic delay (mean duration 6.2 days; mean missed opportunities 1.8). Risk factors for delay included urinary tract infection history (OR 2.1) and morbid obesity (OR 1.6). Visits to more than 1 health care provider/location in a 24-hour period significantly decreased delay risk.

CONCLUSIONS

Nearly 50% of insured patients who undergo debridement for, or die from, necrotizing soft tissue infections of the genitalia will present to a medical provider with a symptomatically similar diagnosis suggestive of early disease development. Many of these visits likely represent diagnostic delay. Efforts to minimize logistic and cognitive biases in this rare condition may lead to improved outcomes if they lead to earlier interventions.

The Rapid Reduction of Infection-Related Visits and Antibiotic Use Among People With Cystic Fibrosis After Starting Elexacaftor-Tezacaftor-Ivacaftor

BACKGROUND

People with cystic fibrosis (CF) routinely suffer from recurrent sinopulmonary infections. Such infections require frequent courses of antimicrobials and often involve multidrug-resistant organisms. The goal of this study was to identify real-world evidence for the effectiveness of elexacaftor-tezacaftor-ivacaftor (ELX/TEZ/IVA) in decreasing infection-related visits and antimicrobial use in people with CF.

METHODS

Using IBM MarketScan data, we identified 389 enrollees with CF who began taking ELX/TEZ/IVA before 1 December 2019 and were enrolled from 1 July 2019 to 14 March 2020. We also identified a comparison population who did not begin ELX/TEZ/IVA during the study period. We compared the following outcomes in the 15 weeks before and after medication initiation: total healthcare visits, inpatient visits, infection-related visits, and antimicrobial prescriptions. We analyzed outcomes using both a case-crossover analysis and a difference-in-differences analysis, to control for underlying trends.

RESULTS

For the case-crossover analysis, ELX/TEZ/IVA initiation was associated with the following changes over a 15-week period: change in overall healthcare visit dates, -2.5 (95% confidence interval, -3.31 to -1.7); change in inpatient admissions, -0.16 (-.22 to -.10); change in infection-related visit dates, -0.62 (-.93 to -.31); and change in antibiotic prescriptions, -0.78 (-1.03 to -.54). Results from the difference-in-differences approach were similar.

CONCLUSIONS

We show a rapid reduction in infection-related visits and antimicrobial use among people with CF after starting a therapy that was not explicitly designed to treat infections. Currently, there are >30 000 people living with CF in the United States alone. Given that this therapy is effective for approximately 90% of people with CF, the impact on respiratory infections and antimicrobial use may be substantial.

Frequency and Duration of, and Risk Factors for, Diagnostic Delays Associated with Histoplasmosis

Histoplasmosis is often confused with other diseases leading to diagnostic delays. We estimated the incidence, length of, and risk factors for, diagnostic delays associated with histoplasmosis. Using data from IBM Marketscan, 2001–2017, we found all patients with a histoplasmosis diagnosis. We calculated the number of visits that occurred prior to the histoplasmosis diagnosis and the number of visits with symptomatically similar diagnoses (SSDs). Next, we estimated the number of visits that represented a delay using a simulation-based approach. We also computed the number of potential opportunities for diagnosis that were missed for each patient and the length of time between the first opportunity and the diagnosis. Finally, we identified risk factors for diagnostic delays using a logistic regression model. The number of SSD-related visits increased significantly in the 97 days prior to the histoplasmosis diagnosis. During this period, 97.4% of patients had a visit, and 90.1% had at least one SSD visit. We estimate that 82.9% of patients with histoplasmosis experienced at least one missed diagnostic opportunity. The average delay was 39.5 days with an average of 4.0 missed opportunities. Risk factors for diagnostic delays included prior antibiotic use, history of other pulmonary diseases, and emergency department and outpatient visits, especially during weekends. New diagnostic approaches for histoplasmosis are needed.

Risk for Asymptomatic Household Transmission of Clostridioides difficile Infection Associated with Recently Hospitalized Family Members

We evaluated whether hospitalized patients without diagnosed Clostridioides difficile infection (CDI) increased the risk for CDI among their family members after discharge. We used 2001–2017 US insurance claims data to compare monthly CDI incidence between persons in households with and without a family member hospitalized in the previous 60 days. CDI incidence among insurance enrollees exposed to a recently hospitalized family member was 73% greater than enrollees not exposed, and incidence increased with length of hospitalization among family members. We identified a dose-response relationship between total days of within-household hospitalization and CDI incidence rate ratio. Compared with persons whose family members were hospitalized <1 day, the incidence rate ratio increased from 1.30 (95% CI 1.19–1.41) for 1–3 days of hospitalization to 2.45 (95% CI 1.66–3.60) for >30 days of hospitalization. Asymptomatic C. difficile carriers discharged from hospitals could be a major source of community-associated CDI cases.

Diagnostic delays in infectious diseases

OBJECTIVES

Diagnostic delays are a major source of morbidity and mortality. Despite the adverse outcomes associated with diagnostic delays, few studies have examined the incidence and factors that influence diagnostic delays for different infectious diseases. The objective of this study was to understand the relative frequency of diagnostic delays for six infectious diseases commonly seen by infectious diseases (ID) consultants and to examine contributing factors for these delays.

METHODS

A 25-item survey to examine diagnostic delays in six infectious diseases was sent to all infectious diseases physicians in the Emerging Infections Network (EIN) who provide care to adult patients. Diseases included (1) tuberculosis, (2) non-tuberculous mycobacterial infections, (3) syphilis, (4) epidural abscess, (5) infective endocarditis, and (6) endemic fungal infections (e.g., histoplasmosis, blastomycosis).

RESULTS

A total of 533 of 1,323 (40%) EIN members responded to the survey. Respondents perceived the diagnosis not being considered initially and the appropriate test not being ordered as the two most important contributors to diagnostic delays. Unusual clinical presentations and not consulting ID physicians early enough were also reported as a contributing factor to delays. Responses recorded in open-text fields also indicated errors related to testing as a likely cause of delays; specifically, test-related errors included ordering the wrong laboratory test, laboratory delays (specialized labs not available at the facility), and lab processing delays.

CONCLUSIONS

Diagnostic delays commonly occur for the infectious diseases we considered. The contributing factors we identified are potential targets for future interventions to decrease diagnostic delays.

744. Incidence and Duration of Diagnostic Delays Associated with Dengue Fever

Background

Dengue fever is a prominent emerging arboviral infection in the tropics and subtropics, and an important cause of systemic febrile illness among some international travelers. Signs and symptoms are similar to more common infectious illnesses in temperate climates, and dengue may not be promptly considered when patients seek evaluation.

Methods

We conducted a retrospective cohort study of patients diagnosed with dengue fever using the IBM MarketScan Research database from 2001-2017. We identified cases of dengue fever where patients were enrolled ≥ 1 year prior to the index diagnosis. All healthcare visits in the year prior to the index diagnosis were collected and we identified visits with signs/symptoms compatible with dengue or a diagnosis made of an illness with similar symptoms (e.g., influenza) before the index dengue diagnosis. We used a time-series change-point analysis to identify the time before diagnosis in which symptoms of dengue became more prominent. We conducted a bootstrap-based simulation analysis to estimate the duration and frequency of missed diagnostic opportunities.

Results

We identified 4,449 cases of dengue fever that met eligibility criteria. We found that 2,791 (62.7%) had ≥ 1 healthcare visit(s) prior to diagnosis with characteristic symptoms of dengue recorded. Our simulations analysis supports that 32.9% (95% CI: 31.1-35.0) experienced 1 or more missed opportunities for diagnosis. Among these patients, the average duration of diagnostic delay was 8.26 (CI: 6.32-11.38) days and ~21% of patients had a diagnostic delay of 2 or more weeks. Patients with a delayed diagnosis averaged 2.2 (CI 2.11-2.29) healthcare visits which represented missed opportunities. Missed opportunities were more likely during weekend, ED or outpatient visits.

Conclusion

Dengue fever is not considered in the majority of patients at the time of the initial symptomatic evaluation in the U.S., indicating delays in diagnosis are common. Enhanced education of providers about dengue fever could lead to more prompt diagnosis that should help optimize patient management.

Disclosures

All Authors: No reported disclosures

Incidence, Duration, and Risk Factors Associated With Missed Opportunities to Diagnose Herpes Simplex Encephalitis: A Population-Based Longitudinal Study

Background

Delays in diagnosing herpes simplex encephalitis (HSE) are associated with increased morbidity and mortality. The purpose of this paper is to determine the frequency and duration of diagnostic delays for HSE and risk factors for diagnostic delays.

Methods

Using data from the IBM Marketscan Databases, 2001-2017, we performed a retrospective cohort study of patients with HSE. We estimated the number of visits with HSE-related symptoms before diagnosis that would be expected to occur in the absence of delays and compared this estimate to the observed pattern of visits. Next, we used a simulation-based approach to compute the number of visits representing a delay, the number of missed diagnostic opportunities per case patient, and the duration of delays. We also investigated potential risk factors for delays.

Results

We identified 2667 patients diagnosed with HSE. We estimated 45.9% (95% confidence interval [CI], 43.6%-48.1%) of patients experienced at least 1 missed opportunity; 21.9% (95% CI, 17.3%-26.3%) of these patients had delays lasting >7 days. Risk factors for delays included being seen only in the emergency department, age <65, or a history of sinusitis or schizophrenia.

Conclusions

Many patients with HSE experience multiple missed diagnostic opportunities before diagnosis.

Risk for Clostridioides difficile Infection Among Hospitalized Patients Associated With Multiple Healthcare Exposures Prior to Admission

BACKGROUND

Clostridioides difficile infection (CDI) is a common healthcare-associated infection and is often used as an indicator of hospital safety or quality. However, healthcare exposures occurring prior to hospitalization may increase risk for CDI. We conducted a case-control study comparing hospitalized patients with and without CDI to determine if healthcare exposures prior to hospitalization (ie, clinic visits, antibiotics, family members with CDI) were associated with increased risk for hospital-onset CDI, and how risk varied with time between exposure and hospitalization.

METHODS

Records were collected from a large insurance-claims database from 2001 to 2017 for hospitalized adult patients. Prior healthcare exposures were identified using inpatient, outpatient, emergency department, and prescription drug claims; results were compared between various CDI case definitions.

RESULTS

Hospitalized patients with CDI had significantly more frequent healthcare exposures prior to admission. Healthcare visits, antibiotic use, and family exposures were associated with greater likelihood of CDI during hospitalization. The degree of association diminished with time between exposure and hospitalization. Results were consistent across CDI case definitions.

CONCLUSIONS

Many different prior healthcare exposures appear to increase risk for CDI presenting during hospitalization. Moreover, patients with CDI typically have multiple exposures prior to admission, confounding the ability to attribute cases to a particular stay.

Incidence, duration and risk factors associated with delayed and missed diagnostic opportunities related to tuberculosis: a population-based longitudinal study

OBJECTIVES

Missed opportunities to diagnose tuberculosis are costly to patients and society. In this study, we (1) estimate the frequency and duration of diagnostic delays among patients with active pulmonary tuberculosis and (2) determine the risk factors for experiencing a diagnostic delay.

DESIGN

A retrospective cohort study of patients with tuberculosis using longitudinal healthcare encounters prior to diagnosis.

SETTING

Commercially insured enrollees from the Commercial Claims and Encounters or Medicare Supplemental IBM Marketscan Research Databases, 2001-2017.

PARTICIPANTS

All patients diagnosed with, and receiving treatment for, pulmonary tuberculosis, enrolled at least 365 days prior to diagnosis.

PRIMARY AND SECONDARY OUTCOME MEASURES

We estimated the number of visits with tuberculosis-related symptoms prior to diagnosis that would be expected to occur in the absence of delays and compared this estimate to the observed pattern. We computed the number of visits representing a delay and used a simulation-based approach to estimate the number of patients experiencing a delay, number of missed opportunities per patient and duration of delays (ie, time between diagnosis and earliest missed opportunity). We also explored risk factors for missed opportunities.

RESULTS

We identified 3371 patients diagnosed and treated for active tuberculosis that could be followed up for 1 year prior to diagnosis. We estimated 77.2% (95% CI 75.6% to 78.7%) of patients experienced at least one missed opportunity; of these patients, an average of 3.89 (95% CI 3.65 to 4.14) visits represented a missed opportunity, and the mean duration of delay was 31.66 days (95% CI 28.51 to 35.11). Risk factors for delays included outpatient or emergency department settings, weekend visits, patient age, influenza season presentation, history of chronic respiratory symptoms and prior fluoroquinolone use.

CONCLUSIONS

Many patients with tuberculosis experience multiple missed diagnostic opportunities prior to diagnosis. Missed opportunities occur most commonly in outpatient settings and numerous patient-specific, environment-specific and setting-specific factors increase risk for delays.

Opioid abuse surveillance in patients with endocarditis

BACKGROUND

Opioid abuse is a significant cause of morbidity and mortality in the United States, and injection drug use (IDU) is a common form of opioid abuse. IDU is a major risk factor for infections including infective endocarditis (IE).

OBJECTIVES

To determine the prevalence of opioid abuse among patients with IE in both patient problem lists and diagnostic codes and describe underlying patient characteristics.

METHODS

A retrospective chart review from 1-1-2010 to 11-19-2018 of a large academic medical center's patients with documented IE was performed. Demographic, comorbidity, opioid prescription data and records of drug abuse in both the patient's problem list and ICD9/10 codes were recorded.

RESULTS

Of the 796 patients with documented IE, 105 patients (13.2%) had opioid abuse or related IDU in their problem list, but only 22 received an ICD-9/10 code associated with drug abuse. IE patients with opioid abuse were generally younger (43.6 vs 61.7 years [P < 0.001]), had fewer chronic comorbidities, and were prescribed opioids more often (86.7% vs 53.8% [P < 0.001]).

CONCLUSIONS

Opioid abuse and IDU are commonly recorded in the problem list of patients with IE, but opioid abuse is frequently not listed as a diagnosis in administrative billing codes.

Association of Household Exposure to Primary Clostridioides difficile Infection With Secondary Infection in Family Members

Importance

Clostridioides difficile infection (CDI) is a common hospital-acquired infection. Whether family members are more likely to experience a CDI following CDI in another separate family member remains to be studied.

Objective

To determine the incidence of potential family transmission of CDI.

Design, Setting, and Participants

In this case-control study comparing the incidence of CDI among individuals with prior exposure to a family member with CDI to those without prior family exposure, individuals were binned into monthly enrollment strata based on exposure status (eg, family exposure) and confounding factors (eg, age, prior antibiotic use). Data were derived from population-based, longitudinal commercial insurance claims from the Truven Marketscan Commercial Claims and Encounters and Medicare Supplemental databases from 2001 to 2017. Households with at least 2 family members continuously enrolled for at least 1 month were eligible. CDI incidence was computed within each stratum. A regression model was used to compare incidence of CDI while controlling for possible confounding characteristics.

Exposures

Index CDI cases were identified using inpatient and outpatient diagnosis codes. Exposure risks 60 days prior to infection included CDI diagnosed in another family member, prior hospitalization, and antibiotic use.

Main Outcomes and Measures

The primary outcome was the incidence of CDI in a given monthly enrollment stratum. Separate analyses were considered for CDI diagnosed in outpatient or hospital settings.

Results

A total of 224 818 cases of CDI, representing 194 424 enrollees (55.9% female; mean [SD] age, 52.8 [22.2] years) occurred in families with at least 2 enrollees. Of these, 1074 CDI events (4.8%) occurred following CDI diagnosis in a separate family member. Prior family exposure was significantly associated with increased incidence of CDI, with an incidence rate ratio (IRR) of 12.47 (95% CI, 8.86-16.97); this prior family exposure represented the factor with the second highest IRR behind hospital exposure (IRR, 16.18 [95% CI, 15.31-17.10]). For community-onset CDI cases without prior hospitalization, the IRR for family exposure was 21.74 (95% CI, 15.12-30.01). Age (IRR, 9.90 [95% CI, 8.92-10.98] for ages ≥65 years compared with ages 0-17 years), antibiotic use (IRR, 3.73 [95% CI, 3.41-4.08] for low-risk and 14.26 [95% CI, 13.27-15.31] for high-risk antibiotics compared with no antibiotics), and female sex (IRR, 1.44 [95% CI, 1.36-1.53]) were also positively associated with incidence.

Conclusions and Relevance

This study found that individuals with family exposure may be at significantly greater risk for acquiring CDI, which highlights the importance of the shared environment in the transmission and acquisition of C difficile.

Many Opportunities to Record, Diagnose, or Treat Injection Drug-related Infections Are Missed: A Population-based Cohort Study of Inpatient and Emergency Department Settings

BACKGROUND

Injection drug use (IDU) and IDU-related infections have increased dramatically. However, the incidence of IDU-related infections may be underreported because drug use is not recorded in diagnostic records where associated infections are identified. Our goal was to estimate a more accurate incidence of IDU-related infections by including IDU-related infections not recorded at the time infections are diagnosed.

METHODS

We performed a retrospective cohort study using inpatient and emergency department visits from the Healthcare Cost and Utilization Project for California, Florida, and New York. We identified all patients diagnosed with bacteremia or sepsis, endocarditis, osteomyelitis or septic arthritis, and skin or soft tissue infection. We estimated the incidence of IDU-related infections by identifying cases where drug use was recorded at the time of an infection and cases where drug use was not recorded at the time of infection but within 6 months before or after the infection diagnosis. We also analyzed factors associated with unrecorded IDU.

RESULTS

There has been an increasing trend in the number of IDU-related infections. The annual number of IDU-related infections increased between 105% and 218% after incorporating infections in which drug use was unrecorded. Factors associated with drug use being unrecorded included emergency department diagnosis, the level of hospital experience treating drug use, age <18 years, and having Medicare as the primary payer.

CONCLUSIONS

More than half of all IDU-related infections may be unrecorded in existing surveillance estimates. There may be many missed opportunities to record, diagnose, or treat underlying drug abuse among patients presenting with IDU-related infections.

Diabetic Foot Surveillance Using Mobile Phones and Automated Software Messaging, a Randomized Observational Trial

BACKGROUND

Early detection of diabetic foot ulcers can improve outcomes. However, patients do not always monitor their feet or seek medical attention when ulcers worsen. New approaches for diabetic-foot surveillance are needed. The goal of this study was to determine if patients would be willing and able to regularly photograph their feet; evaluate different foot-imaging approaches; and determine clinical adequacy of the resulting pictures.

METHODS

We recruited adults with diabetes and assigned them to Self Photo (SP), Assistive Device (AD), or Other Party (OP) groups. The SP group photographed their own feet, while the AD group used a selfie stick; the OP group required another adult to photograph the patient's foot. For 8 weeks, we texted all patients requesting that they text us a photo of each foot. The collected images were evaluated for clinical adequacy. Numbers of (i) submitted and (ii) clinically useful images were compared among groups using generalized linear models and generalized linear mixed models.

RESULTS

A total of 96 patients consented and 88 participated. There were 30 patients in SP, 29 in AD, and 29 in OP. The completion rate was 77%, with no significant differences among groups. However, 74.1% of photographs in SC, 83.7% in AD, 92.6% in OP were determined to be clinically adequate, and these differed statistically significantly.

CONCLUSIONS

Patients with diabetes are willing and able to take photographs of their feet, but using selfie sticks or having another adult take the photographs increases the clinical adequacy of the photographs.Level of Evidence: II.

Improving State-Level Influenza Surveillance by Incorporating Real-Time Smartphone-Connected Thermometer Readings Across Different Geographic Domains

Background

Timely estimates of influenza activity are important for clinical and public health practice. However, traditional surveillance sources may be associated with reporting delays. Smartphone-connected thermometers can capture real-time illness symptoms, and these geo-located readings may help improve state-level forecast accuracy.

Methods

Temperature recordings were collected from smart thermometers and an associated mobile phone application. Using temperature recordings, we developed forecasting models of real-time state-reported influenza-like illness (ILI) 2 weeks before the availability of published reports. We compared time-series models that incorporated thermometer readings at various levels of spatial aggregation and evaluated out-of-sample model performance in an adaptive manner comparing each model to baseline models without thermometer information.

Results

More than 12 million temperature readings were recorded from over 500,000 devices from August 30, 2015 to April 15, 2018. Readings were voluntarily reported from anonymous device users, with potentially multiple users for a single device. We developed forecasting models of real-time outpatient ILI for 46 states with sufficient state-reported ILI data. Forecast accuracy improved considerably when information from thermometers was incorporated. On average, thermometer readings reduced the squared error of state-level forecasting by 43% during influenza season and more than 50% in many states. In general, best-performing models tended to result from incorporating thermometer information at multiple levels of spatial aggregation.

Conclusion

Local forecasts of current influenza activity, measured by outpatient ILI, can be improved by incorporating real-time information from mobile-devices. Information aggregated across neighboring states, regions, and the nation can lead to more reliable forecasts, benefiting local surveillance efforts.

198. Chart Validation of an Algorithm for Identifying Patients with Intravenous Drug Use-Associated Endocarditis Using Administrative Code Data

Background

Studies using administrative data have described increasing rates of intravenous drug use (IVDU)-associated infective endocarditis (IE) in the United States. These studies used International Classification of Disease (ICD) diagnosis codes to identify hospitalized patients with IE and any illicit drug use (i.e., opioid, amphetamine, cocaine or sedative), but were hindered by absence of specific ICD codes for IVDU. We reviewed charts to determine the positive predictive value (PPV) of ICD codes for identifying patients with IE and IVDU.

Methods

We examined national Veterans Affairs (VA) administrative data from January 2010 to December 2017 to identify patients hospitalized for a first episode of potential IVDU-associated IE based on inpatient ICD 9 and 10 codes for both IE and any illicit drug use, the algorithm used to identify IVDU-IE in most prior studies. We randomly selected 100 of these patients nationally and reviewed hospital charts to confirm clinical documentation of: (1) IE, (2) any illicit drug use, and (3) current or past IVDU.

Results

We identified 340 patients with concurrent ICD codes for IE and drug use, increasing from 28 in 2010 to 51 in 2017 (82% increase). In chart review of 100 randomly selected patients, the PPV of ICD codes was 93% (95% CI 88–98%) for a documented clinical diagnosis of IE; 96% (95% CI 92–100%) for documented drug use by any route; and 63% (95% CI 53–73%) for documented IVDU. Among the 37% of patients without clinically documented IVDU, 30% (i.e.,11% of total patients) had clinical documentation stating that drug use was only by non-IV routes, 59% (22% of total) had documented drug use without mention of route of use, and 11% (4% of total) had clinical documentation that patients denied any drug use.

Conclusion

The incidence of first hospitalization for IE among patients with ICD codes for drug use increased by 82% from 2010 to 2017 in VA care. Concurrent ICD codes for illicit drug use had moderate PPV for identifying IVDU in setting of IE, largely due to identification of patients using drugs without documented intravenous use. There is a need to develop more accurate case-finding algorithms for identifying patients with IVDU-associated endocarditis, for both epidemiologic surveillance and quality improvement applications.

Disclosures

All authors: No reported disclosures.

An Assessment of Inappropriate Antibiotic Use and Guideline Adherence for Uncomplicated Urinary Tract Infections

BACKGROUND

In 2011, The Infectious Diseases Society of America released a clinical practice guideline (CPG) that recommended short-course antibiotic therapy and avoidance of fluoroquinolones for uncomplicated urinary tract infections (UTIs). Recommendations from this CPG were rapidly disseminated to clinicians via review articles, UpToDate, and the Centers for Disease Control and Prevention website; however, it is unclear if this CPG had an impact on national antibiotic prescribing practices.

METHODS

We performed a retrospective cohort study of outpatient and emergency department visits within a commercial insurance database between January 1, 2009, and December 31, 2013. We included nonpregnant women aged 18-44 years who had an International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis code for a UTI with a concurrent antibiotic prescription. We performed interrupted time series analyses to determine the impact of the CPG on the appropriateness of the antibiotic agent and duration.

RESULTS

We identified 654 432 women diagnosed with UTI. The patient population was young (mean age, 31 years) and had few comorbidities. Fluoroquinolones, nonfirstline agents, were the most commonly prescribed antibiotic class both before and after release of the guidelines (45% vs 42%). Wide variation was observed in the duration of treatment, with >75% of prescriptions written for nonrecommended treatment durations. The CPG had minimal impact on antibiotic prescribing behavior by providers.

CONCLUSIONS

Inappropriate antibiotic prescribing is common for the treatment of UTIs. The CPG was not associated with a clinically meaningful change in national antibiotic prescribing practices for UTIs. Further interventions are necessary to improve outpatient antibiotic prescribing for UTIs.

Comparing Clinical Outcomes of a Pharmacist-Managed Diabetes Clinic to Usual Physician-Based Care

BACKGROUND

This study analyzed the impact of a pharmacist-managed diabetes clinic on clinical outcomes compared to usual care received from primary care providers (PCPs). This comparison may more definitively demonstrate the value of pharmacist management of chronic disease states.

METHODS

Retrospective observational cohort study conducted in patients referred to a pharmacist-managed pharmacotherapy (PT) clinic from July 2009 to October 2014.

RESULTS

For the primary outcome, the absolute change in A1c during the usual care phase was +1.53% (95% confidence interval [CI]: 1.10-1.96, P < .0001) versus an absolute change of -1.63% (95% CI: -1.28 to -1.97, P < .0001) in the intervention phase. For secondary outcomes, diabetes-related hospitalizations (10 vs 6, P = .104) and emergency room (ER) visits (27 vs 8, P = .049) decreased in the intervention phase compared to the usual care phase. The rate of diabetes-related interventions made per patient per year in the usual care phase was 2.7 versus 11.1 in the intervention phase ( P < .0001).

CONCLUSION

Patients referred to the PT clinic had worsening blood glucose control prior to referral, and their control improved after referral to the clinic. Furthermore, there was an improvement in all diabetes-related outcomes in the intervention phase compared to the usual care phase.

Hospital Clostridium difficile infection (CDI) incidence as a risk factor for hospital-associated CDI

BACKGROUND

Environmental risk factors for Clostridium difficile infections (CDIs) have been described at the room or unit level but not the hospital level. To understand the environmental risk factors for CDI, we investigated the association between institutional- and individual-level CDI.

METHODS

We performed a retrospective cohort study using the Healthcare Cost and Utilization Project state inpatient databases for California (2005-2011). For each patient's hospital stay, we calculated the hospital CDI incidence rate corresponding to the patient's quarter of discharge, while excluding each patient's own CDI status. Adjusting for patient and hospital characteristics, we ran a pooled logistic regression to determine individual CDI risk attributable to the hospital's CDI rate.

RESULTS

There were 10,329,988 patients (26,086 cases and 10,303,902 noncases) who were analyzed. We found that a percentage point increase in the CDI incidence rate a patient encountered increased the odds of CDI by a factor of 1.182.

CONCLUSIONS

As a point of comparison, a 1-percentage point increase in the CDI incidence rate that the patient encountered had roughly the same impact on their odds of acquiring CDI as a 55.8-day increase in their length of stay or a 60-year increase in age. Patients treated in hospitals with a higher CDI rate are more likely to acquire CDI.

Targeted candidate gene screens using CRISPR/Cas9 technology

In the postgenomic era, the ability to quickly, efficiently, and inexpensively assign function to the zebrafish proteome is critical. Clustered regularly interspaced short palindromic repeats (CRISPRs) have revolutionized the ability to perform reverse genetics because of its simplicity and broad applicability. The CRISPR system is composed of an engineered, gene-specific single guide RNA (sgRNA) and a Cas9 enzyme that causes double-stranded breaks in DNA at the targeted site. This simple, two-part system, when injected into one-cell stage zebrafish embryos, efficiently mutates target loci at a frequency such that injected embryos phenocopy known mutant phenotypes. This property allows for CRISPR-based F0 screening in zebrafish, which provides a means to screen through a large number of candidate genes for their role in a phenotype of interest. While there are important considerations for any successful genetic screen, CRISPR screening has significant benefits over conventional methods and can be accomplished in any lab with modest molecular biology experience.

Missed Opportunities to Diagnose Tuberculosis Are Common Among Hospitalized Patients and Patients Seen in Emergency Departments

Background. Delayed diagnosis of tuberculosis (TB) may lead to worse outcomes and additional TB exposures.

Methods. To estimate the potential number of misdiagnosed TB cases, we linked all hospital and emergency department (ED) visits in California′s Healthcare Cost and Utilization Project (HCUP) databases (2005–2011). We defined a potential misdiagnosis as a visit with a new, primary diagnosis of TB preceded by a recent respiratory-related hospitalization or ED visit. Next, we calculated the prevalence of potential missed TB diagnoses for different time windows. We also computed odds ratios (OR) comparing the likelihood of a previous respiratory diagnosis in patients with and without a TB diagnosis, controlling for patient and hospital characteristics. Finally, we determined the correlation between a hospital′s TB volume and the prevalence of potential TB misdiagnoses.

Results. Within 30 days before an initial TB diagnosis, 15.9% of patients (25.7% for 90 days) had a respiratory-related hospitalization or ED visit. Also, within 30 days, prior respiratory-related visits were more common in patients with TB than other patients (OR = 3.83; P < .01), controlling for patient and hospital characteristics. Respiratory diagnosis-related visits were increasingly common until approximately 90 days before the TB diagnosis. Finally, potential misdiagnoses were more common in hospitals with fewer TB cases (ρ = −0.845; P < .01).

Conclusions. Missed opportunities to diagnose TB are common and correlate inversely with the number of TB cases diagnosed at a hospital. Thus, as TB becomes infrequent, delayed diagnoses may increase, initiating outbreaks in communities and hospitals.

Incidence of advanced intravenous access in 2 urban EDs

BACKGROUND

In an emergency department (ED), intravenous (IV) access is frequently accomplished by inspection and palpation of peripheral veins. Failure of these methods indicates severe IV access difficulty and necessitates advanced techniques. Here, we estimate the incidence of advanced IV access in 2 urban EDs with varying resident coverage.

METHODS

In this multiple-cohort study, we enrolled data from 2 neighboring urban EDs-a tertiary care ED and a community hospital affiliate. The 2 have similar volumes but the tertiary care ED has more resident coverage (112 vs 20 hours/d). In a prospective data collection (April 2012-2013), we enrolled consecutive patients during hours of scheduled shifts for research assistants. In a retrospective data collection (March 2011-2012), we reviewed charts of a random sample of patients from each ED for similar outcomes. We calculated the incidence of advanced IV access by dividing the number requiring advanced techniques by the number requiring IV access.

RESULTS

We determined IV outcomes for 790 patients in the prospective cohort and 669 patients in the retrospective cohort. Between groups, there was no difference in the incidence of advanced IV access in the prospective collection (P = .08) or in the retrospective collection (P = .7). Pooling data from both cohorts and both hospitals, the overall incidence was 3.2 [95% confidence interval, 1.9-5.2] per 100 attempts.

CONCLUSION

Advanced IV access is needed in 3.2% of IV attempts in 2 urban EDs with varying levels of resident coverage. We found similar incidence in both EDs.

Condylar fractures of the proximal and middle phalanges

We describe the treatment of 74 patients with phalangeal condylar fractures. Twelve patients presenting with undisplaced fractures were initially treated nonoperatively; of these, five displaced, requiring fixation. The remaining seven patients, all children, united uneventfully. Sixty-two patients presenting with displaced fractures were treated with internal fixation using a single lag screw through a lateral approach. The patients were treated semi-electively on a day surgery unit. Twenty-seven patients with unicondylar fractures, all operated on within 2 weeks of injury, regained full range of movement. Thirty-eight patients had loss of extension (range 10-35°) with fixed flexion contractures at the proximal interphalangeal and thumb interphalangeal joints and extensor lag at the distal interphalangeal joints (overall mean extension loss 10°). Although fixation was technically easier during the first week, a delay of 2 weeks before fixation made little difference to the outcome. In our experience, fractures can be taken down and fixed internally even 8 weeks after injury. If nonoperative treatment is initially embarked upon, close monitoring is required with weekly radiographs up to 3 weeks, as these fractures will frequently displace.

Optimal screening strategies for healthcare associated infections in a multi-institutional setting

Health institutions may choose to screen newly admitted patients for the presence of disease in order to reduce disease prevalence within the institution. Screening is costly, and institutions must judiciously choose which patients they wish to screen based on the dynamics of disease transmission. Since potentially infected patients move between different health institutions, the screening and treatment decisions of one institution will affect the optimal decisions of others; an institution might choose to “free-ride” off the screening and treatment decisions of neighboring institutions. We develop a theoretical model of the strategic decision problem facing a health care institution choosing to screen newly admitted patients. The model incorporates an SIS compartmental model of disease transmission into a game theoretic model of strategic decision-making. Using this setup, we are able to analyze how optimal screening is influenced by disease parameters, such as the efficacy of treatment, the disease recovery rate and the movement of patients. We find that the optimal screening level is lower for diseases that have more effective treatments. Our model also allows us to analyze how the optimal screening level varies with the number of decision makers involved in the screening process. We show that when institutions are more autonomous in selecting whom to screen, they will choose to screen at a lower rate than when screening decisions are more centralized. Results also suggest that centralized screening decisions have a greater impact on disease prevalence when the availability or efficacy of treatment is low. Our model provides insight into the factors one should consider when choosing whether to set a mandated screening policy. We find that screening mandates set at a centralized level (i.e. state or national) will have a greater impact on the control of infectious disease.

Healthcare associated infections are a major cause of morbidity and mortality. Screening patients on admission to the hospital may reduce prevalence by identifying infected individuals; infected individuals can then be treated or isolated to prevent further spread. Because screening is costly, institutions must weigh the benefits of reduced prevalence against the costs of screening. However, patients move between institutions carrying disease with them; consequently, when choosing who to screen, institutions must also consider the rates at which neighboring institutions screen patients as well. We develop a theoretical model that describes this strategic decision process. Using this model we are able to analyze the screening decision problem along three dimensions: (1) how disease specific parameters, such as the effectiveness of treatment, influence the optimal screening level, (2) how the degree of centralization in screening policy (e.g. local, state or federal) influences the optimal screening level, and (3) how these two sets of factors combine to influence the optimal screening level. Our model highlights factors to consider when choosing to implement screening policy, and results are of use to policy makers wishing to reduce the prevalence of infectious disease.

Gender differences in enrolment in an HIV-treatment programme in rural Lesotho, 2006-2008: a brief report

The southern African nation of Lesotho has an HIV seroprevalence of approximately 25%. To address the need for HIV care in rural Lesotho, a project called the Rural Health Initative (RHI) was launched in seven clinics in 2006. Data on enrolment were collected retrospectively and analysed for trends in gender enrolment over time. Of 6001 enrolled, 3904 were women (65.1%) and 2097 (34.9%) were men. When analysed by month of enrolment, there was a higher percentage of men enrolled in December compared with the other months of the year (χ(2) = 15.98, P < 0.001). This may be due to the migratory work of the men in the mines of South Africa and suggests a need for targeted interventions to increase male enrolments over the entire calendar year.

Alcohol use and the management of multidrug-resistant tuberculosis in Tomsk, Russian Federation

SETTING

Alcohol use increases the risk of multidrug-resistant tuberculosis (MDR-TB) and poses challenges for successful MDR-TB treatment, including the potential for additional adverse events.

AIM

To investigate the association between alcohol consumption during MDR-TB treatment and adverse events and treatment outcomes in a cohort of patients in Tomsk, Russia.

DESIGN

From 2000 to 2004, retrospective data were collected on 407 MDR-TB patients in Tomsk. Factors associated with treatment outcomes were assessed using logistic regression.

RESULTS

Of the 407 patients, 253 (62.2%) consumed alcohol during treatment ('drinkers'), and 367 (90.2%) had at least one documented adverse advent. No significant differences were noted in frequency of adverse events in drinkers vs. non-drinkers. Drinkers had less favourable treatment outcomes (OR 0.28, 95%CI 0.18-0.45). Among drinkers, favourable treatment outcome was associated with adherence to at least 80% of prescribed doses (OR 2.89, 95%CI 1.30-6.43) and the occurrence of an adverse event requiring treatment interruption (OR 2.49, 95%CI 1.11-5.59).

CONCLUSIONS

Alcohol use did not appear to increase the risk of adverse events during MDR-TB treatment; however, alcohol consumption was associated with poor outcome. Our findings suggest that individuals who drink alcohol should receive aggressive attention to optimise treatment adherence and manage adverse events.

Continuous intravenous infusion of ketamine for maintenance sedation

Ketamine HCl is a rapidly acting general anesthetic with sedative and analgesic properties that has been reported to have favorable effects on the cardiovascular and pulmonary systems. The goal of this review is to determine the hemodynamic and pulmonary effects of continuous intravenous (IV) ketamine infusion in mechanically ventilated patients, and to determine whether sufficient evidence exists to support its use as an agent for maintenance anesthesia. PubMed/Medline, EMBASE, and Index Medicus databases as well as relevant bibliographies were searched. Studies were independently evaluated for inclusion and exclusion criteria, as well as study parameters, by two evaluators. Any discrepancy was resolved by a third evaluator. Twenty studies (281 patients) met the inclusion criteria for this review including 11 prospective studies (250 patients). Data suggests that ketamine decreases airway resistance, improves dynamic compliance, and preserves functional residual capacity, minute ventilation and tidal volume, while retaining protective pharyngeal and laryngeal reflexes. In patients with refractory bronchospasm, continuous infusion of intravenous ketamine decreases audible wheeze, bronchodilator requirements, and hypercarbia. It also improves respiratory rate and oxygenation, and does not promote respiratory depression. Additionally, ketamine does not result in significant perturbations in blood pressure, heart rate, or vascular resistance. Ketamine may be a safe and effective tool for maintenance sedation of mechanically ventilated patients, however a large prospective clinical trial is warranted.

Controlled trial of active tuberculosis case finding in a Brazilian favela

SETTING

A large, impoverished squatters' settlement (favela), Rio de Janeiro, Brazil.

OBJECTIVE

To assess the community impact of active case finding for tuberculosis (TB) compared to an enhanced case-finding strategy.

DESIGN

A pair-matched, cluster-randomized trial comparing household symptom screening and spot sputum collection (Arm 1) vs. distribution of an educational pamphlet (Arm 2) was performed in a large Brazilian favela. We compared TB case-notification rates, time from symptom onset to treatment start and treatment completion proportions between arms. Fourteen neighborhoods (estimated population 58,587) were pair-matched by prior TB case rates and randomly allocated to one of two interventions. TB was diagnosed using acid-fast bacilli smears. New TB cases were interviewed and clinic records were reviewed.

RESULTS

A total of 193 TB cases were identified in the 14 study neighborhoods (incidence proportion 329 per 100,000 population). The case identification rate in Arm 1 was 934/100,000 person-years (py) vs. 604/100,000 py in Arm 2 (RR 1.55, 95%CI 1.10-1.99). No significant differences were found in time from cough onset to treatment start or proportion completing treatment.

CONCLUSIONS

A door-to-door case-finding campaign was more effective (while ongoing) at detecting prevalent cases and influencing people to come for care than leafleting, but no differences were seen in time to treatment start or treatment completion.

The effect of weaner diet protein content and diet quality on the long-term performance of pigs to slaughter

Short and long-term effects of manipulating dietary CP content and diet quality in weaner diets on health and performance of pigs were investigated in a 2 x 2 factorial combination of CP inclusion (high-CP, 230 g of CP/kg vs. low-CP, 170 g of CP/kg) and diet quality (high-quality, cooked cereals, and animal protein vs. low-quality, raw cereals, and plant protein). Diets were fed ad libitum for 14 d postweaning to pigs weaned at 29.4+/-3.1 d of age and 9.9+/-1.0 kg of BW. From d 14 to slaughter at 104+/-3 kg, all pigs were fed the same series of standard commercial diets. There were 15 replicates per treatment in the weaner phase (<30 kg) and 5 replicates per treatment in the grower-finisher phase (>30 kg). High-quality diets promoted gut health as indicated by improved fecal lactobacilli to coliform ratio (P=0.002) and decreased fecal enterotoxigenic Escherichia coli counts on d 11 postweaning (P=0.028), reducing the risk of postweaning diarrhea and improving pig health from weaning to the end of the weaner phase. Reducing CP content had no effect on gut health. High-CP (P=0.053) and high-quality (P=0.025) diets independently increased ADG during the first 14 d postweaning compared with low-CP and low-quality diets, respectively. There were no interactions between dietary CP content and quality on any of the response criteria investigated. Despite differences in the immediate postweaning period, there was no effect of manipulating diet quality or CP content for 2 wk postweaning on lifetime performance with pigs reaching slaughter weight in 128+/-7 d. These results indicate that high-quality diets may protect pig gut health during the immediate postweaning period. However, it may be possible to use less expensive, decreased quality weaner diets without any adverse effects on long-term performance when weaning older, heavier pigs and where health status, environmental control, and stock management are all maintained to a high standard.

The pathway study: results of a pilot feasibility study in patients suspected of having lung carcinoma investigated in a conventional chest clinic setting compared to a centralised two-stop pathway

The best chance of cure in non-small cell lung cancer (NSCLC) is surgical resection, but UK rates of 8% compare poorly to 25% in the USA and Europe. Delays in diagnosis in the current UK system may be one reason for such discrepancy. To address this problem we set up a rapid diagnostic system and compared it to the conventional method of investigations in a pilot randomised trial.

METHODS

Eighty-eight patients were prospectively enrolled from three District General Hospitals and randomised to either investigation locally or to the rapid system at The Royal Marsden Hospital. The pilot end-points were feasibility and audit of radical treatment rates to enable estimates for patient numbers for the full study.

RESULTS

Forty-five and 43 patients were in the central and conventional arms, respectively (65% male, median age 69 years). There was a 4-week improvement in time to first treatment in those in the central arm (P=0.0025) with 13/30 (43%) and 9/27 (33%) patients having radical treatment in the central and conventional arms, respectively. Patients in the conventional arm felt the diagnostic process was too slow (P=0.02) while those in the central arm seemed to have a better care experience (P=0.01). There were significantly less visits to the general practitioner (GP) in the central arm (P=0.02).

CONCLUSIONS

This pilot study demonstrates that the full study is feasible but would require the commitment and involvement of a large number of patients and physicians. The results show several advantages to investigations and diagnosis in the central arm, particularly in time to treatment initiation, patient satisfaction and rate of radical treatments. The improved rate of radical treatment could lead to an improved survival rate.

Radiation biodosimetry: applications for spaceflight

The multiparametric dosimetry system that we are developing for medical radiological defense applications could be adapted for spaceflight environments. The system complements the internationally accepted personnel dosimeters and cytogenetic analysis of chromosome aberrations, considered the best means of documenting radiation doses for health records. Our system consists of a portable hematology analyzer, molecular biodosimetry using nucleic acid and antigen-based diagnostic equipment, and a dose assessment management software application. A dry-capillary tube reagent-based centrifuge blood cell counter (QBC Autoread Plus, Becton [correction of Beckon] Dickinson Bioscience) measures peripheral blood lymphocytes and monocytes, which could determine radiation dose based on the kinetics of blood cell depletion. Molecular biomarkers for ionizing radiation exposure (gene expression changes, blood proteins) can be measured in real time using such diagnostic detection technologies as miniaturized nucleic acid sequences and antigen-based biosensors, but they require validation of dose-dependent targets and development of optimized protocols and analysis systems. The Biodosimetry Assessment Tool, a software application, calculates radiation dose based on a patient's physical signs and symptoms and blood cell count analysis. It also annotates location of personnel dosimeters, displays a summary of a patient's dosimetric information to healthcare professionals, and archives the data for further use. These radiation assessment diagnostic technologies can have dual-use applications supporting general medical-related care.

Clonal relationships in a shelter-associated outbreak of drug-resistant tuberculosis: 1983-1997

SETTING

An outbreak of tuberculosis caused by Mycobacterium tuberculosis resistant to isoniazid and streptomycin (HS-resistant) was documented in Boston's homeless population in 1984. Isolate relatedness was confirmed at the time by phage typing. In the late 1990s, cases of HS-resistant tuberculosis in the homeless were also documented, confirmed by RFLP typing using IS6110. None of the phage typed isolates from the 1980s were viable for performing RFLP analysis. We attempted to determine, using mixed-linker PCR (M-L PCR) finger-printing, whether or not these cases were all due to the same strain of M. tuberculosis.

DESIGN

Isolates from 10 HS-resistant patients-four non-viable isolates from the 1980s and six viable isolates from 1996-1997-were sent to the Centers for Disease Control and Prevention for M-L PCR fingerprinting. These results were combined with record reviews of older cases and an ongoing epidemiologic investigation.

RESULTS

Eight of 10 of the isolates were clonal, and the other two were strongly suspected matches. Epidemiologic investigation determined that transmission continued to occur after the initial outbreak in 1984-1985, and that a streptomycin-monoresistant variant of the strain was also circulating.

CONCLUSION

M-L PCR fingerprinting combined with epidemiology was able to document links between cases across 15 years.