A generalized linear mixed models approach for detecting incident clusters of disease in small areas, with an application to biological terrorism

Since the intentional dissemination of anthrax through the US postal system in the fall of 2001, there has been increased interest in surveillance for detection of biological terrorism. More generally, this could be described as the detection of incident disease clusters. In addition, the advent of affordable and quick geocoding allows for surveillance on a finer spatial scale than has been possible in the past. Surveillance for incident clusters of disease in both time and space is a relatively undeveloped arena of statistical methodology. Surveillance for bioterrorism detection, in particular, raises unique issues with methodological relevance. For example, the bioterrorism agents of greatest concern cause initial symptoms that may be difficult to distinguish from those of naturally occurring disease. In this paper, the authors propose a general approach to evaluating whether observed counts in relatively small areas are larger than would be expected on the basis of a history of naturally occurring disease. They implement the approach using generalized linear mixed models. The approach is illustrated using data on health-care visits (1996–1999) from a large Massachusetts managed care organization/multispecialty practice group in the context of syndromic surveillance for anthrax. The authors argue that there is great value in using the geographic data

Does bicycling contribute to the risk of erectile dysfunction? Results from the Massachusetts Male Aging Study (MMAS)

An association between bicycling and erectile dysfunction (ED) has been described previously, but there are limited data examining this association in a random population of men. Such data would incorporate bicyclists with varied types of riding and other factors. Data from the Massachusetts Male Aging Study (MMAS) were utilized to examine the association between bicycling and ED. Logistic regression was used to test for an association, controlling for age, energy expenditure, smoking, depression and chronic illness. Bicycling less than 3 h per week was not associated with ED and may be somewhat protective. Bicycling 3 h or more per week may be associated with ED. Data revealed that there may be a reduced probability of ED in those who ride less than 3 h per week and ED may be more likely in bikers who ride more than 3 h per week. More population-based research is needed to better define this relationship

A New Surrogate Variable for Erectile Dysfunction Status in the Massachusetts Male Aging Study

Erectile dysfunction (ED) is the subject of a vast clinical literature, but little information has been gathered from random samples of the general public. The Massachusetts Male Aging Study (MMAS) addressed this important aspect of men\u27s health. The MMAS was conducted in two waves, with baseline data collection in 1987–1989 and follow-up in 1995–1997. Subsequent to the baseline MMAS survey, a consensus developed that subjective measures are optimal for defining ED. Unfortunately, the baseline questionnaire did not ask subjects directly about their erectile functioning. Thus, we previously assigned the MMAS subjects a degree of impotence at baseline using a series of related questions, employing a discriminant formula constructed from a separate sample of urology clinic patients. At follow-up the men classified themselves directly in addition to answering the original series of related questions. In the present article, we report the results of a new discriminant function, based on the MMAS men at follow-up. We also compare the two methods and discuss our reasons for preferring the internally calibrated method

Using Automated Health Plan Data to Assess Infection Risk from Coronary Artery Bypass Surgery

We determined if infection indicators were sufficiently consistent across health plans to allow comparison of hospitals’ risks of infection after coronary artery bypass surgery. Three managed care organizations accounted for 90% of managed care in eastern Massachusetts, from October 1996 through March 1999. We searched automated inpatient and outpatient claims and outpatient pharmacy dispensing files for indicator codes suggestive of postoperative surgical site infection. We reviewed full text medical records of patients with indicator codes to confirm infection status. We compared the hospital-specific proportions of cases with an indicator code, adjusting for health plan, age, sex, and chronic disease score. A total of 536 (27%) of 1,953 patients had infection indicators. Infection was confirmed in 79 (53%) of 149 reviewed records with adequate documentation. The proportion of patients with an indicator of infection varied significantly (p<0.001) between hospitals (19% to 36%) and health plans (22% to 33%). The difference between hospitals persisted after adjustment for health plan and patients’ age and sex. Similar relationships were observed when postoperative antibiotic information was ignored. Automated claims and pharmacy data from different health plans can be used together to allow inexpensive, routine monitoring of indicators of postoperative infection, with the goal of identifying institutions that can be further evaluated to determine if risks for infection can be reduced

Air quality and error quantity: pollution and performance in a high-skilled, quality-focused occupation

We provide the first evidence that short-term exposure to air pollution affects the work performance of a group of highly-skilled, quality-focused employees. We repeatedly observe the decision-making of individual professional baseball umpires, quasi-randomly assigned to varying air quality across time and space. Unique characteristics of this setting combined with high-frequency data disentangle effects of multiple pollutants and identify previously under-explored acute effects. We find a 1 ppm increase in 3-hour CO causes an 11.5% increase in the propensity of umpires to make incorrect calls and a 10 mg/m3 increase in 12-hour PM2.5 causes a 2.6% increase. We control carefully for a variety of potential confounders and results are supported by robustness and falsification checks

Epidemiology and risk factors for Staphylococcus aureus colonization in children in the post-PCV7 era

BACKGROUND: The incidence of community-associated methicillin-resistant Staphylococcus aureus (MRSA) has risen dramatically in the U.S., particularly among children. Although Streptococcus pneumoniae colonization has been inversely associated with S. aureus colonization in unvaccinated children, this and other risk factors for S. aureus carriage have not been assessed following widespread use of the heptavalent pneumococcal conjugate vaccine (PCV7). Our objectives were to (1) determine the prevalence of S. aureus and MRSA colonization in young children in the context of widespread use of PCV7; and (2) examine risk factors for S. aureus colonization in the post-PCV7 era, including the absence of vaccine-type S. pneumoniae colonization. METHODS: Swabs of the anterior nares (S. aureus) were obtained from children enrolled in an ongoing study of nasopharyngeal pneumococcal colonization of healthy children in 8 Massachusetts communities. Children 3 months to <7 years of age seen for well child or sick visits in primary care offices from 11/03-4/04 and 10/06-4/07 were enrolled. S. aureus was identified and antibiotic susceptibility testing was performed. Epidemiologic risk factors for S. aureus colonization were collected from parent surveys and chart reviews, along with data on pneumococcal colonization. Multivariate mixed model analyses were performed to identify factors associated with S. aureus colonization. RESULTS: Among 1,968 children, the mean age (SD) was 2.7 (1.8) years, 32% received an antibiotic in the past 2 months, 2% were colonized with PCV7 strains and 24% were colonized with non-PCV7 strains. The prevalence of S. aureus colonization remained stable between 2003-04 and 2006-07 (14.6% vs. 14.1%), while MRSA colonization remained low (0.2% vs. 0.9%, p = 0.09). Although absence of pneumococcal colonization was not significantly associated with S. aureus colonization, age (6-11 mo vs. > or =5 yrs, OR 0.39 [95% CI 0.24-0.64]; 1-1.99 yrs vs. > or =5 yrs, OR 0.35 [0.23-0.54]; 2-2.99 yrs vs. > or =5 yrs, OR 0.45 [0.28-0.73]; 3-3.99 yrs vs. > or =5 yrs, OR 0.53 [0.33-0.86]) and recent antibiotic use were significant predictors in multivariate models. CONCLUSION: In Massachusetts, S. aureus and MRSA colonization remained stable from 2003-04 to 2006-07 among children <7 years despite widespread use of pneumococcal conjugate vaccine. S. aureus nasal colonization varies by age and is inversely correlated with recent antibiotic use

Quality and correlates of medical record documentation in the ambulatory care setting

BACKGROUND: Documentation in the medical record facilitates the diagnosis and treatment of patients. Few studies have assessed the quality of outpatient medical record documentation, and to the authors' knowledge, none has conclusively determined the correlates of chart documentation. We therefore undertook the present study to measure the rates of documentation of quality of care measures in an outpatient primary care practice setting that utilizes an electronic medical record. METHODS: We reviewed electronic medical records from 834 patients receiving care from 167 physicians (117 internists and 50 pediatricians) at 14 sites of a multi-specialty medical group in Massachusetts. We abstracted information for five measures of medical record documentation quality: smoking history, medications, drug allergies, compliance with screening guidelines, and immunizations. From other sources we determined physicians' specialty, gender, year of medical school graduation, and self-reported time spent teaching and in patient care. RESULTS: Among internists, unadjusted rates of documentation were 96.2% for immunizations, 91.6% for medications, 88% for compliance with screening guidelines, 61.6% for drug allergies, 37.8% for smoking history. Among pediatricians, rates were 100% for immunizations, 84.8% for medications, 90.8% for compliance with screening guidelines, 50.4% for drug allergies, and 20.4% for smoking history. While certain physician and patient characteristics correlated with some measures of documentation quality, documentation varied depending on the measure. For example, female internists were more likely than male internists to document smoking history (odds ratio [OR], 1.90; 95% confidence interval [CI], 1.27 – 2.83) but were less likely to document drug allergies (OR, 0.51; 95% CI, 0.35 – 0.75). CONCLUSIONS: Medical record documentation varied depending on the measure, with room for improvement in most domains. A variety of characteristics correlated with medical record documentation, but no pattern emerged. Further study could lead to targeted interventions to improve documentation

Multicenter Evaluation of a Novel Surveillance Paradigm for Complications of Mechanical Ventilation

Ventilator-associated pneumonia (VAP) surveillance is time consuming, subjective, inaccurate, and inconsistently predicts outcomes. Shifting surveillance from pneumonia in particular to complications in general might circumvent the VAP definition's subjectivity and inaccuracy, facilitate electronic assessment, make interfacility comparisons more meaningful, and encourage broader prevention strategies. We therefore evaluated a novel surveillance paradigm for ventilator-associated complications (VAC) defined by sustained increases in patients' ventilator settings after a period of stable or decreasing support.We assessed 600 mechanically ventilated medical and surgical patients from three hospitals. Each hospital contributed 100 randomly selected patients ventilated 2-7 days and 100 patients ventilated >7 days. All patients were independently assessed for VAP and for VAC. We compared incidence-density, duration of mechanical ventilation, intensive care and hospital lengths of stay, hospital mortality, and time required for surveillance for VAP and for VAC. A subset of patients with VAP and VAC were independently reviewed by a physician to determine possible etiology.Of 597 evaluable patients, 9.3% had VAP (8.8 per 1,000 ventilator days) and 23% had VAC (21.2 per 1,000 ventilator days). Compared to matched controls, both VAP and VAC prolonged days to extubation (5.8, 95% CI 4.2-8.0 and 6.0, 95% CI 5.1-7.1 respectively), days to intensive care discharge (5.7, 95% CI 4.2-7.7 and 5.0, 95% CI 4.1-5.9), and days to hospital discharge (4.7, 95% CI 2.6-7.5 and 3.0, 95% CI 2.1-4.0). VAC was associated with increased mortality (OR 2.0, 95% CI 1.3-3.2) but VAP was not (OR 1.1, 95% CI 0.5-2.4). VAC assessment was faster (mean 1.8 versus 39 minutes per patient). Both VAP and VAC events were predominantly attributable to pneumonia, pulmonary edema, ARDS, and atelectasis.Screening ventilator settings for VAC captures a similar set of complications to traditional VAP surveillance but is faster, more objective, and a superior predictor of outcomes

Giving an Account of One’s Pain in the Anthropological Interview

In this paper, I analyze the illness stories narrated by a mother and her 13-year-old son as part of an ethnographic study of child chronic pain sufferers and their families. In examining some of the moral, relational and communicative challenges of giving an account of one’s pain, I focus on what is left out of some accounts of illness and suffering and explore some possible reasons for these elisions. Drawing on recent work by Judith Butler (Giving an Account of Oneself, 2005), I investigate how the pragmatic context of interviews can introduce a form of symbolic violence to narrative accounts. Specifically, I use the term “genre of complaint” to highlight how anthropological research interviews in biomedical settings invoke certain typified forms of suffering that call for the rectification of perceived injustices. Interview narratives articulated in the genre of complaint privilege specific types of pain and suffering and cast others into the background. Giving an account of one’s pain is thus a strategic and selective process, creating interruptions and silences as much as moments of clarity. Therefore, I argue that medical anthropologists ought to attend more closely to the institutional structures and relations that shape the production of illness narratives in interview encounters