When Zebras Run with Horses: The Diagnostic Dilemma of Acute Aortic Dissection Complicated by Myocardial Infarction

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72234/1/j.1540-8183.2002.tb01107.x.pd

Using machine learning to model dose–response relationships

Rationale, aims and objectivesEstablishing the relationship between various doses of an exposure and a response variable is integral to many studies in health care. Linear parametric models, widely used for estimating dose–response relationships, have several limitations. This paper employs the optimal discriminant analysis (ODA) machine‐learning algorithm to determine the degree to which exposure dose can be distinguished based on the distribution of the response variable. By framing the dose–response relationship as a classification problem, machine learning can provide the same functionality as conventional models, but can additionally make individual‐level predictions, which may be helpful in practical applications like establishing responsiveness to prescribed drug regimens.MethodUsing data from a study measuring the responses of blood flow in the forearm to the intra‐arterial administration of isoproterenol (separately for 9 black and 13 white men, and pooled), we compare the results estimated from a generalized estimating equations (GEE) model with those estimated using ODA.ResultsGeneralized estimating equations and ODA both identified many statistically significant dose–response relationships, separately by race and for pooled data. Post hoc comparisons between doses indicated ODA (based on exact P values) was consistently more conservative than GEE (based on estimated P values). Compared with ODA, GEE produced twice as many instances of paradoxical confounding (findings from analysis of pooled data that are inconsistent with findings from analyses stratified by race).ConclusionsGiven its unique advantages and greater analytic flexibility, maximum‐accuracy machine‐learning methods like ODA should be considered as the primary analytic approach in dose–response applications.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134965/1/jep12573_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134965/2/jep12573.pd

Survival by the Fittest: Hospital‐Level Variation in Quality of Resuscitation Care

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/139113/1/jah3453.pd

Antithrombotic Therapy and Outcomes After ICD Implantation in Patients With Atrial Fibrillation and Coronary Artery Disease: An Analysis From the National Cardiovascular Data Registry (NCDR)®

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/112259/1/jah3831.pd

Do physicians examine patients in contact isolation less frequently? A brief report

Background: Patients who are hospitalized and infected with multi drug-resistant bacteria are usually placed in contact isolation, which requires hospital personnel to gown and glove before patient examination. Contact isolation with active culture surveillance appears beneficial in preventing the spread of drug-resistant infections; however, contact isolation may impede the ability to examine patients as a result of the additional effort required to gown and glove. We assessed whether patients who are hospitalized and placed under contact precautions are examined less often by second- and third-year medical residents (ie, senior medical residents), and attending physicians during morning rounds. Method: We conducted a prospective cohort study on the inpatient medical services at 2 university-affiliated medical centers. We directly observed senior medical residents and attending physicians during morning rounds, and recorded the contact precaution status of the patient and whether they were examined by either physician. Results: Of a total of 139 patients, 31 (22%) were in contact isolation. Senior medical residents examined 26 of 31 patients (84%) in contact isolation versus 94 of 108 patients (87%) not in contact isolation (relative risk, 0.96; 95% confidence interval, 0.81-1.14; P = .58). In comparison, attending physicians examined 11 of 31 patients (35%) in contact isolation versus 79 of 108 patients (73%) not in contact isolation (relative risk, 0.49; 95% confidence interval, 0.30-0.79; P \u3c .001). Discussion: Attending physicians are about half as likely to examine patients in contact isolation compared with patients not in contact isolation

Do physicians examine patients in contact isolation less frequently? A brief report

Background: Patients who are hospitalized and infected with multi drug-resistant bacteria are usually placed in contact isolation, which requires hospital personnel to gown and glove before patient examination. Contact isolation with active culture surveillance appears beneficial in preventing the spread of drug-resistant infections; however, contact isolation may impede the ability to examine patients as a result of the additional effort required to gown and glove. We assessed whether patients who are hospitalized and placed under contact precautions are examined less often by second- and third-year medical residents (ie, senior medical residents), and attending physicians during morning rounds. Method: We conducted a prospective cohort study on the inpatient medical services at 2 university-affiliated medical centers. We directly observed senior medical residents and attending physicians during morning rounds, and recorded the contact precaution status of the patient and whether they were examined by either physician. Results: Of a total of 139 patients, 31 (22%) were in contact isolation. Senior medical residents examined 26 of 31 patients (84%) in contact isolation versus 94 of 108 patients (87%) not in contact isolation (relative risk, 0.96; 95% confidence interval, 0.81-1.14; P = .58). In comparison, attending physicians examined 11 of 31 patients (35%) in contact isolation versus 79 of 108 patients (73%) not in contact isolation (relative risk, 0.49; 95% confidence interval, 0.30-0.79; P \u3c .001). Discussion: Attending physicians are about half as likely to examine patients in contact isolation compared with patients not in contact isolation

Longitudinal study of short‐term corticosteroid use by working‐age adults with diabetes mellitus: Risks and mitigating factors

BackgroundThis study assessed the frequency of short‐term oral corticosteroid use in adults with diabetes, examined the incidence of fractures, venous thromboembolism (VTE), and hospitalization for sepsis after corticosteroid use, and evaluated whether preventative medications mitigated adverse events.MethodsA longitudinal study (2012–14) was conducted of 1 548 945 adults (aged 18–64 years) who received healthcare coverage through a large national health insurer. Incidence rate ratios (IRR) were calculated using conditional Poisson regression.ResultsShort‐term oral corticosteroids were used by 23.9%, 20.8%, and 20.9% of adults with type 2 diabetes, type 1 diabetes, and no diabetes, respectively, during the 3‐year period (P < 0.001). Baseline risks of fracture, VTE, and sepsis were greater for individuals with than without diabetes (P < 0.001). The combined effect of having diabetes and using corticosteroids was greater than the sum of the individual effects (synergy indices of 1.17, 1.23, 1.30 for fracture, VTE, and sepsis, respectively). The IRR for VTE in the 5–30 days after corticosteroid use was 3.62 (95% confidence interval [CI] 2.41–5.45). Fractures increased in the 5–30 days after corticosteroid use (IRR 2.06; 95% CI 1.52, 2.80), but concomitant use of ergocalciferol mitigated this risk (IRR 1.13; 95% CI 0.12, 11.07). The risk of hospitalization for sepsis was elevated with corticosteroid use (IRR 3.79; 95% CI 2.05, 7.01), but was mitigated by the concomitant use of statins.ConclusionsShort‐term oral corticosteroid use is common in adults with diabetes and is associated with an elevated, but low, risk of adverse events. The findings suggest that preventative medications may mitigate risk.摘要背景这项研究在成年糖尿病患者中评估了短期使用口服糖皮质激素的频率,  调查了使用糖皮质激素后骨折与静脉血栓栓塞(venous thromboembolism, VTE)的发生率以及脓毒症的住院率,  并且评估了预防性用药是否会减少不良事件。方法这是一项在1548945名具有大型国家健康保险公司医疗保险的成年(年龄为18‐64岁)患者中进行的纵向研究(2012‐14)。使用有条件的Poisson回归分析来计算发病率比(incidence rate ratios, IRR)。结果在这3年期间,  短期使用口服糖皮质激素治疗的2型糖尿病、1型糖尿病以及非糖尿病成年患者的比例分别为23.9%、20.8%与20.9%(P < 0.001)。与非糖尿病患者相比,  糖尿病患者基线时的骨折、VTE以及脓毒症的风险都更高(P < 0.001)。患糖尿病以及使用糖皮质激素的联合效应大于个体效应之和(骨折、VTE以及脓毒症的协同指数分别为1.17、1.23、1.30)。使用糖皮质激素后的5‐30日内发生VTE的IRR为3.62(95%置信区间[CI]为2.41‐5.45)。使用糖皮质激素后的5‐30日内发生骨折的风险增加(IRR为2.06;95% CI为1.52, 2.80),  但同时使用麦角骨化醇治疗可以减少这种风险(IRR为1.13;95% CI为0.12, 11.07)。使用糖皮质激素后脓毒症的住院风险也增加了(IRR为3.79;95% CI为2.05, 7.01),  但是同时使用他汀类药物治疗可以减少这种风险。结论成年糖尿病患者短期使用口服糖皮质激素治疗很常见并且与不良事件风险轻度升高有关。这项研究结果表明预防性用药可以减少这种风险。HighlightsAdults with diabetes mellitus have a greater risk of fracture, venous thromboembolism, and sepsis than those without diabetes; the use of corticosteroids, even for short durations, increases this risk.Vitamin D mitigated the risk of fracture in patients with diabetes who used corticosteroids, and statins decreased the likelihood of hospitalization for sepsis in corticosteroid users with diabetes.Corticosteroids should be used with caution in patients with diabetes and mitigating factors should be considered.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/144644/1/jdb12631.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/144644/2/jdb12631_am.pd

Evaluation of atrial fibrillation using wearable device signals and home blood pressure data in the Michigan Predictive Activity & Clinical Trajectories in Health (MIPACT) Study: A Subgroup Analysis (MIPACT-AFib)

BackgroundThe rising adoption of wearable technology increases the potential to identify arrhythmias. However, specificity of these notifications is poorly defined and may cause anxiety and unnecessary resource utilization. Herein, we report results of a follow-up screening protocol for incident atrial fibrillation/flutter (AF) within a large observational digital health study.MethodsThe MIPACT Study enrolled 6,765 adult patients who were provided an Apple Watch and blood pressure (BP) monitors. From March to July 2019, participants were asked to contact the study team for any irregular heart rate (HR) notification. They were assessed using structured questionnaires and asked to provide 6 Apple Watch EKGs. Those with arrhythmias or non-diagnostic EKGs were sent 7-day monitors. The EHR was reviewed after 3 years to determine if participants developed arrhythmias.Results86 participants received notifications and met inclusion criteria. Mean age was 50.5 (SD 16.9) years, and 46 (53.3%) were female. Of 76 participants assessed by the study team, 32 (42.1%) reported anxiety surrounding notifications. Of 59 participants who sent at least 1 EKG, 52 (88.1%) were in sinus rhythm, 3 (5.1%) AF, 2 (3.4%) indeterminate, and 2 (3.4%) sinus bradycardia. Cardiac monitor demonstrated AF in 2 of 3 participants with AF on Apple Watch EKGs. 2 contacted their PCPs and were diagnosed with AF. In total, 5 cases of AF were diagnosed with 1 additional case identified during EHR review.ConclusionWearable devices produce alarms that can frequently be anxiety provoking. Research is needed to determine the implications of these alarms and appropriate follow-up

Effect of Testing and Treatment on Emergency Department Length of Stay Using a National Database

Objectives:  Testing and treatment are essential aspects of the delivery of emergency care. Recognition of the effects of these activities on emergency department (ED) length of stay (LOS) has implications for administrators planning efficient operations, providers, and patients regarding expectations for length of visit; researchers in creating better models to predict LOS; and policy‐makers concerned about ED crowding. Methods:  A secondary analysis was performed using years 2006 through 2008 of the National Hospital Ambulatory Medical Care Survey (NHAMCS), a nationwide study of ED services. In univariate and bivariate analyses, the authors assessed ED LOS and frequency of testing (blood test, urinalysis, electrocardiogram [ECG], radiograph, ultrasound, computed tomography [CT], or magnetic resonance imaging [MRI]) and treatment (providing a medication or performance of a procedure) according to disposition (discharged or admitted status). Two sets of multivariable models were developed to assess the contribution of testing and treatment to LOS, also stratified by disposition. The first was a series of logistic regression models to provide an overview of how testing and treatment activity affects three dichotomized LOS cutoffs at 2, 4, and 6 hours. The second was a generalized linear model (GLM) with a log‐link function and gamma distribution to fit skewed LOS data, which provided time costs associated with tests and treatment. Results:  Among 360 million weighted ED visits included in this analysis, 227 million (63%) involved testing, 304 million (85%) involved treatment, and 201 million (56%) involved both. Overall, visits with any testing were associated with longer LOS (median = 196 minutes; interquartile range [IQR] = 125 to 305 minutes) than those with any treatment (median = 159 minutes; IQR = 91 to 262 minutes). This difference was more pronounced among discharged patients than admitted patients. Obtaining a test was associated with an adjusted odds ratio (OR) of 2.29 (95% confidence interval [CI] = 1.86 to 2.83) for experiencing a more than 4‐hour LOS, while performing a treatment had no effect (adjusted OR = 0.84; 95% CI = 0.68 to 1.03). The most time‐costly testing modalities included blood test (adjusted marginal effects on LOS = +72 minutes; 95% CI = 66 to 78 minutes), MRI (+64 minutes; 95% CI = 36 to 93 minutes), CT (+59 minutes; 95% CI = 54 to 65 minutes), and ultrasound (US; +56 minutes; 95% CI = 45 to 67 minutes). Treatment time costs were less substantial: performing a procedure (+24 minutes; 95% CI = 20 to 28 minutes) and providing a medication (+15 minutes; 95% CI = 8 to 21 minutes). Conclusions:  Testing and less substantially treatment were associated with prolonged LOS in the ED, particularly for blood testing and advanced imaging. This knowledge may better direct efforts at streamlining delivery of care for the most time‐costly diagnostic modalities or suggest areas for future research into improving processes of care. Developing systems to improve efficient utilization of these services in the ED may improve patient and provider satisfaction. Such practice improvements could then be examined to determine their effects on ED crowding.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/92123/1/j.1553-2712.2012.01353.x.pd