The paradox of the "body mass index paradox" in dialysis patients: associations of adiposity with inflammation.
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Body Mass Index↗
Biomedical subjects
Matthew H Samore
Publications and source records attributed to Matthew H Samore.
Antimicrobial resistance determinants and future control.
At the beginning of the 21st century, antimicrobial resistance is common, has developed against every class of antimicrobial drug, and appears to be spreading into new clinical niches. We describe determinants likely to influence the future epidemiology and health impact of antimicrobial-resistant infections. Understanding these factors will ultimately optimize preventive strategies for an unpredictable future.
Anti-Bacterial Agents↗
Drug-resistant Escherichia coli, Rural Idaho.
Stool carriage of drug-resistant Escherichia coli in home-living residents of a rural community was examined. Carriage of nalidixic acid-resistant E. coli was associated with recent use of antimicrobial agents in the household. Household clustering of drug-resistant E. coli was observed. Most carriers of drug-resistant E. coli lacked conventional risk factors.
Adolescent↗
Clarifying adverse drug events: a clinician's guide to terminology, documentation, and reporting.
Adverse drug events cause substantial morbidity and mortality, yet they remain underappreciated and misunderstood. The terminology to describe errors and patient harm associated with medications causes much confusion. This article uses the case study of a patient with multiple adverse drug events to clarify key terms, such as adverse event, adverse drug reaction, adverse drug event, medication error, and side effect. The case discussion illustrates clinical approaches to analyzing the causal connection between a suspect drug and an adverse event. Examples and rationale for meaningful documentation of adverse drug events are provided, along with an outline of the types of events that should be reported to regulatory agencies.
Adverse Drug Reaction Reporting Systems↗
Surveillance of medical device-related hazards and adverse events in hospitalized patients.
CONTEXT: Although adverse drug events have been extensively evaluated by computer-based surveillance, medical device errors have no comparable surveillance techniques. OBJECTIVES: To determine whether computer-based surveillance can reliably identify medical device-related hazards (no known harm to patient) and adverse medical device events (AMDEs; patient experienced harm) and to compare alternative methods of detection of device-related problems. DESIGN, SETTING, AND PARTICIPANTS: This descriptive study was conducted from January through September 2000 at a 520-bed tertiary teaching institution in the United States with experience in using computer tools to detect and prevent adverse drug events. All 20 441 regular and short-stay patients (excluding obstetric and newborn patients) were included. MAIN OUTCOME MEASURES: Medical device events as detected by computer-based flags, telemetry problem checklists, International Classification of Diseases, Ninth Revision (ICD-9) discharge code (which could include AMDEs present at admission), clinical engineering work logs, and patient survey results were compared with each other and with routine voluntary incident reports to determine frequencies, proportions, positive predictive values, and incidence rates by each technique. RESULTS: Of the 7059 flags triggered, 552 (7.8%) indicate a device-related hazard or AMDE. The estimated 9-month incidence rates (number per 1000 admissions [95% confidence intervals]) for AMDEs were 1.6 (0.9-2.5) for incident reports, 27.7 (24.9-30.7) for computer flags, and 64.6 (60.4-69.1) for ICD-9 discharge codes. Few of these events were detected by more than 1 surveillance method, giving an overall incidence of AMDE detected by at least 1 of these methods of 83.7 per 1000 (95% confidence interval, 78.8-88.6) admissions. The positive predictive value of computer flags for detecting device-related hazards and AMDEs ranged from 0% to 38%. CONCLUSIONS: More intensive surveillance methods yielded higher rates of medical device problems than found with traditional voluntary reporting, with little overlap between methods. Several detection methods had low efficiency in detecting AMDEs. The high rate of AMDEs suggests that AMDEs are an important patient safety issue, but additional research is necessary to identify optimal AMDE detection strategies.
Adult↗
Risk factors associated with ampicillin-resistant infection in newborns in the era of group B streptococcal prophylaxis.
OBJECTIVES: To document the trend of ampicillin-resistant infections in newborns weighing at least 1500 g and to determine factors associated with ampicillin-resistant neonatal early-onset infection in the era of routine group B streptococcal prophylaxis. DESIGN: Case-control study. SETTING: Referral hospital with level I through level III nurseries.Patients Newborns aged 0 to 7 days with cultures positive for bacterial infection, born from January 1994 to August 2002 (n = 53). Random controls were matched to admission year and nursery level (n = 159). MAIN OUTCOME MEASURES: Trends of and factors associated with ampicillin-resistant infections. RESULTS: Trends in our institution were the same as those found in some recent reports, a decrease in group B streptococcal early-onset infections without a concomitant increase in gram-negative early-onset infections. Specifically, when stratified by birth weight, newborns weighing at least 1500 g had no increase in gram-negative pathogens in the eras both before and after group B streptococcal prophylaxis (0.8 per 1000 live births to 0.3 per 1000 live births; incidence ratio, 2.3 [95% confidence interval, 0.5-10.9]). No increase in ampicillin resistance was seen during the same 3 periods (50%, 60%, and 50%, respectively; P =.97). Independent risk factors associated with ampicillin-resistant early-onset infection were intrapartum antibiotics for a 24-hour duration or longer (odds ratio, 4.8 [95% confidence interval, 1.0-23.3]) and clinical chorioamnionitis (odds ratio, 9.2 [95% confidence interval, 2.6-32.9]). CONCLUSIONS: No increase in early-onset infections with gram-negative or ampicillin-resistant pathogens was detected. Ampicillin-resistant early-onset infection was associated with intrapartum antibiotics given for 24 hours or longer prior to delivery and with clinical chorioamnionitis. Ampicillin sodium and gentamicin sulfate remain appropriate initial antibiotic therapies for early-onset infection in newborns weighing at least 1500 g and without these risk factors.
Ampicillin Resistance↗
Assessing the status of infection control programs in small rural hospitals in the western United States.
BACKGROUND: Organized infection control (IC) interventions have been successful in reducing the acquisition of hospital-associated infections. Rural community hospitals, although contributing significantly to the US health care system, have rarely been assessed regarding the nature and quality of their IC programs. METHODS: A sample of 77 small rural hospitals in Idaho, Nevada, Utah, and eastern Washington completed a written survey in 2000 regarding IC staffing, infrastructure support, surveillance of nosocomial infections, and IC policies and practices. RESULTS: Almost all hospitals (65 of 67, 97%) had one infection control practitioner (ICP), and 29 of 61 hospitals (47.5%) reported a designated physician with IC oversight. Most ICPs (62 of 64, 96.9%) were also employed for other activities outside of IC. The median number of ICP hours per week for IC activities was 10 (1-40), equating to a median of 1.56 (0.30-21.9) full-time ICPs per 250 hospital beds. Most hospitals performed total house surveillance for nosocomial infections (66 of 73, 90.4%) utilizing Centers for Disease Control and Prevention (CDC) definitions (69 of 74, 93.2%). Most also monitored employee bloodborne exposures (69 of 73, 94.5%). All hospitals had a written bloodborne pathogen exposure plan and isolation policies. CDC guidelines were typically followed when developing IC policies. Access to medical literature and online resources appeared to be limited for many ICPs. CONCLUSIONS: Most rural hospitals surveyed have expended reasonable resources to develop IC programs that are patterned after those seen in larger hospitals and conform to recommendations of consensus expert panels. Given these hospitals' small patient census, short length of stay, and low infection rates, further studies are needed to evaluate necessary components of effective IC programs in these settings that efficiently utilize limited resources without compromising patient care.
Centers for Disease Control and Prevention, U.S.↗
Malnutrition and atherosclerosis in dialysis patients.
Longitudinal associations of malnutrition with atherosclerotic events in uremia are unclear. In 50,732 incident Medicare dialysis patients who had normal (18.5 to 24.9 kg/m(2)), low (<18.5 kg/m(2)), or high (> or = 25 kg/m(2)) body mass index (BMI) and initiated dialysis in the United States from January 1995 to December 1999 with reported measured creatinine clearances and acute coronary syndrome (ACS; International Classification of Diseases, Ninth Revision codes 410.x and 411.x) were examined in parametric survival models. Normal BMI was the referent group. Twenty-four-hour urinary creatinine (UCr) was used as a measure of muscle mass. There were 7213 (14.2%) hospitalized ACS events, 1528 (22%) of which were fatal (death within 30 d). One-year post-ACS mortality was 48%. Low BMI (hazard ratio [HR], 0.89; P = 0.02] was associated with lower hazard, and UCr was not predictive (NS) of hospitalized ACS in multivariable model. Low BMI (NS) was not associated with a composite end point of hospitalized ACS/suspected out-of-hospital ACS death, whereas lowest UCr quartile was associated with higher hazard (HR, 1.14; P < 0.001). Low BMI (HR, 1.24; P < 0.001) and decrease in UCr (highest quartile reference, second quartile HR, 1.11 [P < 0.001]; third quartile HR, 1.24 [P < 0.001]; and fourth quartile HR, 1.43 [P < 0.001]) were associated with increased hazard of death. Hospitalized ACS events in dialysis patients carry very high immediate and long-term mortality. Positive longitudinal associations of malnutrition with documented hospitalized ACS events could not be demonstrated. Further longitudinal studies are warranted to provide definitive evidence of malnutrition as a uremic risk factor for atherosclerosis.
Aged↗
Variety of beta-lactamases produced by amoxicillin-clavulanate-resistant Escherichia coli isolated in the northeastern United States.
This study analyzed the enzymatic basis and molecular epidemiology of amoxicillin-clavulanate-resistant Escherichia coli isolated by the microbiology laboratory of a United States tertiary care hospital. From October 1998 to December 1999, all E. coli isolates were screened for ampicillin-sulbactam resistance. Of 283 isolates that tested resistant to ampicillin-sulbactam, 69 unique patient isolates were also resistant to amoxicillin-clavulanate by disk diffusion testing (zone diameter </= 13 mm). These amoxicillin-clavulanate-resistant E. coli isolates underwent agar dilution testing, pulsed-field gel electrophoresis, PCR analysis, and isoelectric focusing. The mean age of study patients was 52 years; 78% were female. Among the isolates, 12 were nosocomial (rate of amoxicillin-clavulanate resistance = 4.7%) and 57 were community acquired (rate of amoxicillin-clavulanate resistance = 2.8%). No predominant strain was identified. By agar dilution testing, 67 isolates were nonsusceptible (39 resistant and 28 intermediate) to amoxicillin-clavulanate and 37 were piperacillin-tazobactam resistant but only 8 were ceftazidime resistant (ceftazidime MIC >/= 32 micro g/ml). Two isolates were susceptible to amoxicillin-clavulanic acid by agar dilution, although they were resistant by disk diffusion testing. The distribution of beta-lactamases was as follows: the TEM type alone was found in 52 isolates, the AmpC type was found in 4 isolates (2 identified as containing CMY-2), the TEM type and CMY-2 were found in 2 isolates, and the OXA type was found in 1 isolate. Also, there was one isolate with the TEM type and the SHV type and one with the TEM type and a second, unidentified enzyme. Among the isolates with TEM-type enzymes, two extended-spectrum beta-lactamase-producing isolates were identified but two isolates with inhibitor-resistant TEM (IRT) enzymes (one with TEM-34 [IRT-6] and the other with a novel enzyme [tentatively assigned the designation TEM-122]) were more interesting.
Adolescent↗
System-wide surveillance for clinical encounters by patients previously identified with MRSA and VRE.
Methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE) have emerged as major infection control problems worldwide. Patients previously infected or colonized with MRSA or VRE need to be identified and often isolated as soon as they visit a health care facility. Infection control personnel usually are not aware when these patients enter their facilities. We developed a system-wide surveillance system to alert infection control personnel when patients with previous MRSA or VRE cultures from LDS Hospital have subsequent clinical encounters at any inpatient or outpatient facility at Intermountain Health Care (IHC). This paper describes this system and includes the results from an initial study on the potential epidemiological benefits provided to help improve patient care. The study found that patients with previous MRSA and VRE had subsequent encounters at 62 different IHC facilities up to 304 miles away from 1 day to over 5 years later. In addition, the new surveillance system was able to alert infection control personnel when ever these patients visited any IHC inpatient or outpatient facility.
Enterococcus↗
Transmission dynamics and control of severe acute respiratory syndrome.
Severe acute respiratory syndrome (SARS) is a recently described illness of humans that has spread widely over the past 6 months. With the use of detailed epidemiologic data from Singapore and epidemic curves from other settings, we estimated the reproductive number for SARS in the absence of interventions and in the presence of control efforts. We estimate that a single infectious case of SARS will infect about three secondary cases in a population that has not yet instituted control measures. Public-health efforts to reduce transmission are expected to have a substantial impact on reducing the size of the epidemic.
Contact Tracing↗
Geographic diversity and temporal trends of antimicrobial resistance in Streptococcus pneumoniae in the United States.
Resistance of Streptococcus pneumoniae to antibiotics is increasing throughout the United States, with substantial variation among geographic regions. We show that patterns of geographic variation are best explained by the intensity of selection for resistance, which is reflected by differences between the proportions of resistance within individual serotypes, rather than by differences between the frequencies of particular serotypes. Using a mathematical transmission model, we analyzed temporal trends in the proportions of singly and dually resistant organisms and found that pneumococcal strains resistant to both penicillin and erythromycin are increasing faster than strains singly resistant to either. Using the model, we predict that by 1 July 2004, in the absence of a vaccine, 41% of pneumococci at the Centers for Disease Control and Prevention (CDC)'s Active Bacterial Core surveillance (ABCs) sites, taken together, will be dually resistant, with 5% resistant to penicillin only and 5% to erythromycin only.
Drug Resistance↗
Evaluation of antibiotic use in a hospital with an antibiotic restriction policy.
The study was designed to evaluate rational antibiotic use in relation to diagnosis and bacteriological findings. All hospitalized patients who received antibiotics were evaluated by a cross-sectional study. Of the 713 patients hospitalized, 281 (39.4%) patients received 377 antibiotics. Among 30 different antibiotics the most frequently requested were first generation cephalosporins (19.9%), ampicillin-sulbactam (19.1%) and aminoglycosides (11.7%). Antibiotic use was appropriate in 64.2% of antibiotic requests. In analysis of appropriate use, a request after an infectious diseases consultation was a frequent reason (OR=14, P<0.001, CI=0.02-0.24). Antibiotics requested in conjunction with susceptibility results were found to be more appropriate than those ordered empirically (OR=4.5, P=0.017, CI=0.06-0.76). Inappropriate antibiotic use was significantly higher among unrestricted antibiotics than restricted ones (P<0.001). Irrational antibiotic use was high for unrestricted antibiotics. Additional interventions such as postgraduate training programmes and elaboration of local guidelines could be beneficial.
Anti-Bacterial Agents↗
Shortage of penicillin G: impact on antibiotic prescribing at a US tertiary care centre.
A six-year retrospective study was undertaken to examine the effect of the recent penicillin G (penG) shortage on antibiotic prescribing practices at a tertiary care centre in the US. Prior to the shortage, penG was predominantly used for intrapartum prophylaxis of group B streptococcal disease. As the supply of penG ended temporarily in October 1999, penG use declined dramatically, ampicillin replaced penG in obstetrics and a shift to broad-spectrum agents was noted in non-obstetric patients potentially eligible for penG treatment. Shortage-triggered treatment changes had a negative effect on prescribing patterns, which may contribute to antibiotic resistance.
Adult↗
Creatinine production, nutrition, and glomerular filtration rate estimation.
This study examined the validity and clinical implications of the assumption of the Modification of Diet in Renal Disease Study (MDRD) formula that age, gender, race, and BUN account for creatinine production (CP). The relationships of MDRD GFR, CP, and nutrition were examined in 1074 Dialysis Morbidity and Mortality Study Wave II patients with reported measured creatinine clearances at initiation of dialysis. Age, gender, race, BUN, and serum creatinine (Scr) were used to calculate MDRD GFR. The measured 24-h urinary creatinine was used to estimate CP. In linear regression, Scr positively correlated with CP independent of age, gender, race, and BUN. Compared with the highest CP quartile, the lowest CP quartile had lower creatinine clearance (5.8 +/- 2.9 versus 11.3 +/- 3.4 ml/min, P <.01) despite lower Scr (5.8 +/- 2.6 versus 8.6 +/- 3.1 mg%, P <.01). There was an excellent correlation between the reciprocal of Scr and the MDRD GFR (r = 0.90). As a result, the MDRD GFR was higher in the lowest CP quartile (10.9 +/- 4.6 versus 7.6 +/- 2.4 ml/min, P <.01). Malnutrition (48% versus 26%, P <.01) was more common in the lowest CP quartile. Each 5-ml/min increase in MDRD GFR was associated with 21% higher odds of malnutrition (P = 0.046) in a multivariable logistic regression, which was abolished by controlling for CP. The fundamental assumption of the MDRD formula is invalid in patients with advanced renal failure, and the use of this formula in these patients might introduce biases.
Adult↗
Impact of timing of initiation of dialysis on mortality.
Previous studies showed that sicker patients were initiated on dialysis at higher GFR as estimated by the Modification of Diet in Renal Disease (MDRD) formula. It was previously shown that patients with low creatinine production were malnourished and had low serum creatinine levels and creatinine clearances (CrCl) but high MDRD GFR at initiation of dialysis. Therefore, a propensity score approach was used to examine the associations of MDRD GFR and measured CrCl at the initiation of dialysis with subsequent mortality. Baseline data and outcomes were obtained from the Dialysis Morbidity Mortality Study Wave II. Propensity scores for early initiation derived by logistic regression were used in Cox models to examine mortality. Each 5-ml/min increase in MDRD GFR at initiation of dialysis in the entire cohort was associated with increased hazard of death in multivariable Cox model (hazard ratio [HR] 1.14; P = 0.002). In the subgroup of patients with reported CrCl, higher MDRD GFR was associated with increased risk of death (for each 5-ml/min increase, HR 1.27; P < 0.001) but not CrCl (for each 5-ml/min increase, HR 0.98; P = 0.81). These divergent results might reflect erroneous GFR estimation by the MDRD formula. Furthermore, these data do not support earlier initiation of dialysis. Therefore, for patients without clinical indications for initiation of dialysis, the appropriate GFR level for initiation of dialysis is unknown.
Adult↗
Clinical and economic outcomes of conventional amphotericin B-associated nephrotoxicity.
A retrospective 9-year cohort study was conducted to identify the hospitalization costs, length of hospital stay, and mortality associated with nephrotoxicity (NT) among 494 inpatients who were treated with conventional amphotericin B (CAB). Survival regression methods were used to model the effect of NT. The rate of NT was 12%; the overall in-hospital mortality rate was 22%. After adjustment for confounding, NT was associated with a 2.7-fold higher risk of death (P<.001). Although the unadjusted effects of NT on length of hospital stay and hospitalization costs after the initiation of CAB were consistent with small increases, such effects were not significant in multivariate models (time ratio, 1.2 [P=.2]; cost ratio, 1.1 [P=.8]). The greater the number of days before the onset of NT that were included in the analysis, the greater the apparent effect of NT on costs. CAB-associated NT was associated with increased mortality, but it did not impact the costs and length of hospital stay.
Amphotericin B↗
The effects of comorbid conditions on the outcomes of patients undergoing peritoneal dialysis.
PURPOSE: Dialysis patients frequently have comorbid conditions. We examined the effects of age and comorbid conditions on technique failure (i.e., transfer to hemodialysis), death, hospital costs, and kidney transplantation in patients treated with peritoneal dialysis. METHODS: We studied 97 patients who began peritoneal dialysis from January 1, 1993, to December 31, 1998, at the University of Pittsburgh outpatient dialysis unit. Demographic characteristics, comorbid conditions, and outcomes were determined by reviewing the Medical Archival Retrieval System database and outpatient records. Because the comorbidity (Charlson) score was colinear with age, we used a modified version of the score without an age component. Low, moderate, and high comorbidity groups were defined based on the 33rd and 66th percentiles of the comorbidity score. RESULTS: In multivariate-adjusted models, each decade increase in age was associated with an increased risk of death (hazard ratio [HR] = 1.7; 95% confidence interval [CI]: 1.1 to 2.5) and technique failure (HR = 1.5; 95% CI: 1.0 to 2.3). High (versus low) comorbidity was associated with an increased risk of death or technique failure (HR = 3.5; 95% CI: 1.0 to 12) and significantly higher average inpatient costs. There were no differences in age or comorbidity score between patients who transferred to hemodialysis and those who died. CONCLUSION: Patients who are older and more ill have a greater risk of death and of transfer to hemodialysis from peritoneal dialysis.
Age Factors↗