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Biomedical subjects

Mark G Weiner

Publications and source records attributed to Mark G Weiner.

11 recordsLinked to original sources
PubMed2006

Imipenem resistance among pseudomonas aeruginosa isolates: risk factors for infection and impact of resistance on clinical and economic outcomes.

OBJECTIVES: To identify risk factors for infection with imipenem-resistant Pseudomonas aeruginosa and determine the impact of imipenem resistance on clinical and economic outcomes among patients infected with P. aeruginosa. DESIGNS: An ecologic study, a case-control study, and a retrospective cohort study. SETTING: A 625-bed tertiary care medical center. PATIENTS: All patients who had an inpatient clinical culture positive for P. aeruginosa between January 1, 1999, and December 31, 2000. RESULTS: From 1991 through 2000, the annual prevalence of imipenem resistance among P. aeruginosa isolates increased significantly (P<.001 by the chi (2) test for trend). Among 879 patients infected with P. aeruginosa during 1999-2000, a total of 142 had imipenem-resistant P. aeruginosa infection (the case group), whereas 737 had imipenem-susceptible P. aeruginosa infection (the control group). The only independent risk factor for imipenem-resistant P. aeruginosa infection was prior fluoroquinolone use (adjusted odds ratio, 2.52 [95% confidence interval {CI}, 1.61-3.92]; P<.001). Compared with patients infected with imipenem-susceptible P. aeruginosa, patients infected with imipenem-resistant P. aeruginosa had longer subsequent hospitalization durations (15.5 days vs 9 days; P=.02) and greater hospital costs (81,330 dollars vs 48,381dollars ; P<.001). The mortality rate among patients infected with imipenem-resistant P. aeruginosa was 31.1%, compared with 16.7% for patients infected with imipenem-susceptible P. aeruginosa (relative risk, 1.86 [95% CI, 1.38-2.51]; P<.001). In multivariable analyses, there remained an independent association between infection with imipenem-resistant P. aeruginosa and mortality. CONCLUSIONS: The prevalence of imipenem resistance among P. aeruginosa strains has increased markedly in recent years and has had a significant impact on both clinical and economic outcomes. Our results suggest that curtailing use of other antibiotics (particularly fluoroquinolones) may be important in attempts to curb further emergence of imipenem resistance.

Adult↗
PubMed2006

Identification of optimal combinations for empirical dual antimicrobial therapy of Pseudomonas aeruginosa infection: potential role of a Combination Antibiogram.

To better determine the optimal combinations for empirical dual antimicrobial therapy of Pseudomonas aeruginosa infection, we evaluated the utility of a novel combination antibiogram. Although the combination antibiogram allowed modest fine-tuning of choices for dual antibiotic therapy, selections based on the 2 antibiograms did not differ substantively. Drug combinations with the broadest coverage were consistently composed of an aminoglycoside and a beta-lactam.

Anti-Bacterial Agents↗
PubMed2006

Development and validation of queries using structured query language (SQL) to determine the utilization of comparison imaging in radiology reports stored on PACS.

The purpose of this research was to develop queries that quantify the utilization of comparison imaging in free-text radiology reports. The queries searched for common phrases that indicate whether comparison imaging was utilized, not available, or not mentioned. The queries were iteratively refined and tested on random samples of 100 reports with human review as a reference standard until the precision and recall of the queries did not improve significantly between iterations. Then, query accuracy was assessed on a new random sample of 200 reports. Overall accuracy of the queries was 95.6%. The queries were then applied to a database of 1.8 million reports. Comparisons were made to prior images in 38.69% of the reports (693,955/1,793,754), were unavailable in 18.79% (337,028/1,793,754), and were not mentioned in 42.52% (762,771/1,793,754). The results show that queries of text reports can achieve greater than 95% accuracy in determining the utilization of prior images.

Database Management Systems↗
PubMed2006

Fluoroquinolone-resistant Pseudomonas aeruginosa: assessment of risk factors and clinical impact.

PURPOSE: Pseudomonas aeruginosa infections have been associated with considerable morbidity and mortality. Fluoroquinolones (FQ) are the only oral therapy available for P. aeruginosa infections, but resistance is increasingly prevalent. METHODS: We examined annual trends in FQ-resistant P. aeruginosa (FQRPA) from 1991 to 2000. Subsequently, inpatients with a clinical culture positive for P. aeruginosa between January 1, 1999 and December 31, 2000 were included in a case control study to identify risk factors for FQ resistance and a cohort study to examine the impact of FQ resistance on outcomes in P. aeruginosa. RESULTS: Annual prevalence of FQRPA increased from 15% in 1991 to 41% in 2000 (P <0.001 trend). Between 1999 and 2000, 332 P. aeruginosa isolates were FQ resistant and 540 were FQ susceptible. Prior FQ use was the only independent risk factor for FQRPA (adjusted OR = 3.43; 95% confidence interval [CI] 2.37, 4.96). Subjects with FQRPA had greater median hospital charges (62,325 dollars vs 48,734 dollars) (P =.007) and higher mortality (47.5% vs 35.5%) (P =.004). However, in a multivariate model, only imipenem resistance of the isolate was significantly associated with mortality. FQ resistance was not an independent risk factor. CONCLUSIONS: FQRPA has increased significantly and is associated with prior FQ use. Limiting FQ use may curb the emergence of resistance among P. aeruginosa. FQRPA is associated with increased hospital charges, but other resistance patterns may have a more significant impact on mortality.

Academic Medical Centers↗
PubMed2006

Simulation of the Syst-Eur randomized control trial using a primary care electronic medical record was feasible.

OBJECTIVE: To determine the validity of outcome research using a primary care practice database by comparing a randomized controlled trial (RCT) with a simulated one. STUDY DESIGN AND SETTING: A cohort from the United Kingdom General Practice Research Database (GPRD) was used to simulate the Systolic Hypertension in Europe (Syst-Eur) trial, a study of antihypertensive therapy of isolated systolic hypertension, by replicating all aspects of that RCT (selection criteria, study time frame, treatment, and outcomes) except randomization. RESULTS: The exposed and unexposed groups in the GPRD study exhibited similar baseline characteristics. Stroke, the primary RCT outcome, decreased significantly in both the RCT (incidence rate ratio IRR = 0.58) and the GPRD study (IRR = 0.68). Myocardial infarction decreased nonsignificantly but similarly in both studies (RCT IRR = 0.70; GPRD IRR = 0.74). With the GPRD study extended for 3 years more, myocardial infarction decreased significantly, comparable to findings from the Systolic Hypertension in the Elderly Program (SHEP), another RCT similar to Syst-Eur. CONCLUSIONS: The findings support the potential value of clinical databases to investigate treatment effectiveness. RCT simulation using the GPRD may be the most feasible way to assess observational study validity in comparison to RCTs. The extended GPRD study shows the feasibility of using a simulated study to supplement the results of an RCT of limited duration.

Computer Simulation↗
PubMed2006

The impact of continuous pulse oximetry monitoring on intensive care unit admissions from a postsurgical care floor.

Continuous pulse oximetry (CPOX) has the potential to increase vigilance and decrease pulmonary complications and thus decrease intensive care unit (ICU) admissions. In a randomized nonblinded study of 1219 subjects we compared the effects of CPOX and standard monitoring on the rate of transfer to an ICU from a 33-bed postcardiothoracic surgery care floor. There was no difference in the rate of ICU readmission between the CPOX and standard monitor groups. Despite older age and comorbidity, estimated cost to time of censoring (enrollment to completion of the study) was less in the monitored patients who required ICU transfer than in the unmonitored patients who required ICU transfer (mean estimated cost difference of 28,195 dollars; P = 0.04). Use of CPOX altered the reasons that patients were transferred to an ICU but did not affect the rate of transfer. The duration, and thus estimated cost, of ICU stay was significantly less in the CPOX-monitored group. The potential for CPOX to allow for early intervention, or perhaps prevention of pulmonary complications, needs to be explored. Routine CPOX monitoring did not reduce transfer to ICU, mortality, or overall estimated cost of hospitalization, and it is unclear if there is any real benefit from the application of this technology in patients on a general care floor who are recovering from cardiothoracic surgery.

Aged↗
PubMed2005

Coadministration of oral levofloxacin with agents that impair its absorption: potential impact on emergence of resistance.

Coadministration of fluoroquinolones (FQs) with divalent or trivalent cation-containing compounds (DTCCs) inhibits FQ absorption. In a case-control study of 46 inpatients receiving oral levofloxacin and DTCCs, patients with a levofloxacin-resistant isolate had been previously exposed to nearly twice as many days of levofloxacin/DTCC coadministration (P = 0.04). There remained a borderline significant independent association between the number of days of coadministration and levofloxacin-resistant culture [adjusted odds ratio (95% confidence interval) = 1.26 (0.98, 1.63); P = 0.07], even after controlling for the length of the levofloxacin course and the duration of hospitalisation prior to initiation of levofloxacin. Efforts should be directed at modifying hospital policies for dosing of levofloxacin and DTCCs to prevent coadministration.

Administration, Oral↗
PubMed2005

High rate of coadministration of di- or tri-valent cation-containing compounds with oral fluoroquinolones: risk factors and potential implications.

BACKGROUND: The characteristics of fluoroquinolone use that increase the risk of selecting for fluoroquinolone resistance remain unclear. Exposure to subtherapeutic levels of fluoroquinolone promotes bacterial development of fluoroquinolone resistance. Oral fluoroquinolone absorption is significantly impaired by coadministration with many common di- or tri-valent cation-containing compounds (DTCCs), and this interaction has been associated with therapeutic failure. However, the prevalence of, and risk factors for, in-hospital coadministration of oral fluoroquinolones with DTCCs is unknown. DESIGN: Case-control study. SETTING: A 625-bed, tertiary-care medical center. PATIENTS: All inpatients who were dispensed oral levofloxacin from July 1, 1999, to June 30, 2001, were included. Coadministration was defined by documented administration of any DTCC within 2 hours of levofloxacin. Complete coadministration was defined as coadministration complicating every dose of a course of levofloxacin. RESULTS: A subset of 3,227 (41.0%) of 7,871 doses of levofloxacin that occurred during the same calendar day as any DTCC was selected for further review. Overall, 1,904 (77.1%) of 2,470 doses of oral levofloxacin reviewed were complicated by coadministration with at least one DTCC. On multivariable analysis, an increased number of prescribed medications was significantly associated with complete coadministration (per increase of one medication: OR, 1.05; CI95, 1.01-1.10; P = .036), whereas patient location in an ICU was protective (OR, 0.51; CI95, 0.30-0.87; P = .013). If our prevalence results are extrapolated to all patients receiving oral levofloxacin at our hospital, approximately one in three doses was complicated by coadministration. CONCLUSION: Coadministration of fluoroquinolones with DTCCs is extremely common and significantly associated with polypharmacy.

Administration, Oral↗
PubMed2003

Derivation of malignancy status from ICD-9 codes.

To assess the severity of illness of oncology patients, it is necessary to distinguish patients with a single primary tumor from patients with metastatic disease occurring at a secondary location remote from the primary site. We developed a ranked list of cancer groupings and an algorithm that could distinguish patients with primary and metastatic cancer even if no specific code for secondary cancer was recorded. In patients with metastatic disease, the algorithm should also distinguish the primary site from the secondary site.

Algorithms↗
PubMedDate not supplied

Visits to physicians after the oxygenation of gasoline in Philadelphia.

During the period between 1992 and 1997, there was an increase in levels of methyl tertiary butyl ether (MTBE) in gasoline in the Philadelphia, Pennsylvania, area. In this study, the authors analyzed billing records from clinical practices that were extensions of the University of Pennsylvania. The authors based their selections on the International Classification of Diseases-9 diagnostic codes, which were determined from (1) previous studies of methyl tertiary butyl ether conducted by the Centers for Disease Control; (2) respiratory symptoms, including asthma and wheezing; and (3) symptoms associated anecdotally with methyl tertiary butyl ether levels in gasoline. The authors normalized all data by the total number of office visits. The incidences of headache, throat irritation, allergic rhinitis, cough, nausea, dizziness, upper respiratory infections, wheezing, otitis media, skin rash, anxiety, insomnia, palpitations, generalized allergy, and malaise were increased during the period studied. Large increases occurred during the winters of 1993-1994 and 1994-1995 (during which there were high levels of MTBE), but not in the preceding summers (during which there were low levels of MTBE). This was especially true for asthma and wheezing. During the summers of 1995, 1996, and 1997, the incidences of the aforementioned symptoms increased greatly.

Adult↗