Benjamin Mozes

Comparison of Factors Associated With 30-Day Mortality After Coronary Artery Bypass Grafting in Patients With Versus Without Diabetes Mellitus

The purpose of this study was to identify factors associated with 30-day mortality after coronary artery bypass graft surgery (CABG) among diabetic patients, and to compare them with risk factors among nondiabetics. A subanalysis of a prospective national cohort study was performed which included patients who underwent CABG in 14 medical centers in Israel during 1994. Data including patient demographic and historical information, comorbidity, and cardiac catheterization results were collected by trained nurses. Data were derived from direct patient interviews, charts, catheterization reports, surgical reports, and national vital records. Multivariate logistic regression analysis was used to identify factors associated with a 30-day mortality in diabetic and nondiabetic patient populations. The results showed that crude mortality was 5.0% among diabetic patients (n = 1,034) and 2.5% among nondiabetics (n = 3,350; p < 0.001). The risk profile in diabetics was found to be worse. Multivariate logistic regression analysis identified female gender, 3-vessel disease, and left main disease as independent risk factors for 30-day, past-CABG mortality unique to diabetic patients. Left ventricular dysfunction was found to effect a greater risk among diabetic patients, whereas chronic renal failure was associated with greater risk among nondiabetics. In conclusion, we found differences in patterns of risk factors for post-CABG mortality between diabetics and nondiabetics. These findings may help physicians to identify patients at high risk for CABG mortality.

The relation between objective and subjective impairment in cognitive function among multiple sclerosis patients - the role of depression

Objective: To evaluate the relations between perceived cognitive function and objective cognitive deficit and to assess variables affecting perceived cognitive function among multiple sclerosis (MS) patients. Methods: A cross sectional study of patients with MS. All patients were interviewed and the Expanded Disability Status Scale (EDSS) score was determined. The dependent variables were four items assessing perceived concentration and thinking, attention, memory, and whether others have noticed memory or concentration problems. The explanatory variables were age, sex, duration of disease, number of relapses in the last 2 years, EDSS score, depressive symptoms score (CES-D) and the domains of the Neurobehavioral Cognitive Status Examination (NCSE) assessing cognitive performance. Bivariate and then multivariate analysis were performed. Results: One hundred and sixty-one MS patients were included. Mean age was 44.2 years (s.d. 11.3 years), mean EDSS score was 4.86 (s.d. 1.93). Seventy-two per cent of the patients had objective cognitive impairment and 51% reported decreased perceived cognitive function. In all models assessing perceived cognitive function we could explain only a small part of the variance (R2 ranged between 18-26%). In all these models depressive symptoms explained the highest portion of the variance (partial R2 ranging between 13-26%). The only domain of the NCSE that entered some of the models was calculation (partial R2 ranging between 3-7%). Conclusions: These findings emphasize the gap between objective and subjective assessment of cognitive function and the high correlation between perceived cognitive deficit and depressive symptoms.

A comparison of three measures: the time trade-off technique, global health-related quality of life and the SF-36 in dialysis patients

We investigated the correlation between descriptive and valuational measures of health-related quality of life (HRQL) and assessed determinants affecting these measures. Our suspicion was that there is little similarity in the content of descriptive and valuational measures of HRQL. We thus conducted a cross-sectional observational study of 56 hemodialysis patients. All underwent structured interviews. Dependent variables were patients utilities [time trade-off (TTO)], global rating of HRQL and generic HRQL (SF-36). Independent variables were socioeconomic details, disease severity, comorbidity, symptoms, depression, social support, and laboratory data. The correlation between TTO and global HRQL was -0.33 (P = .0178) and between TTO and the SF-36 physical and mental summary scores -0.16 (P = .2383) and -0.20 (P = .1443), respectively. The regression models for the SF-36 physical and mental summary scores explained 75% and 64% of the variance, and for global HRQL 29% of the variance. The independent variables had no effect on the TTO. This confirmed our suspicion that a qualitative difference exists between TTO and descriptive quality of life tools. The TTO content could not be explained by the variables that entail the content of HRQL instruments.

Do we know what global ratings of health-related quality of life measure?

Information is lacking about the publics perception of the term health-related quality of life (HRQL). Specifically, what are the relations between the domains included in the operational definition of HRQL tools and global health ratings. The purpose of this analysis was to identify factors associated with global rating of HRQL. We conducted a survey of a representative sample of 2,030 Israeli adults, aged 45–75 years. Multiple linear regression analysis was used to identify associations between the dependent variable, the global rating, and socio-economic details, presence of disease states, and each of the domains of the SF-36. The results demonstrate that the model explains only 52% of the variance of the global rating score. The general health domain of the SF-36 explains the vast majority of the variance, 38.5% . Another important explanatory variable was physical functioning domain, which explains 7.0% of the variance and to a lesser extent vitality. The other domains of the SF-36, socio-economic details and presence of disease states contribute only small percentages to the total explained variance of the global ratings of HRQL. It seems that there is a considerable difference between the operational definition of the research community of HRQL and the public perception of this term.

REDUCTION OF REDUNDANT HOSPITAL STAY THROUGH CONTROLLED INTERVENTION

With the aim of reducing redundant hospital stay through controlled intervention, preset criteria for inpatient care were applied on a medical ward. The proportion of unjustified hospital stay days fell by 52.6% and the average length of stay on the experimental ward declined from 6.3 days to 4.6 days. On a control medical ward there was practically no change. At one-month follow-up, patients from the two wards did not differ in death rate, readmission rate, or subjective evaluation of health status.

Factors Affecting Change in Quality of Life After Prostatectomy for Benign Prostatic Hypertrophy: The Impact of Surgical Techniques

PURPOSE The impact of prostatectomy on quality of life was assessed in patients with benign prostatic hypertrophy (BPH) who were classified according to the expected benefit from surgical intervention. The relative impact of the 2 surgical techniques (open versus closed) on short-term quality of life was compared. MATERIALS AND METHODS An observational study was done on 545 consecutive patients with BPH undergoing prostatectomy at 3 medical centers in Israel between 1991 and 1992. Repeated structured interviews preoperatively, and at 4 and 12 months postoperatively were performed, including 6 quality of life questionnaires evaluating BPH specific (symptom severity and symptom effect) and generic (activity, independence, mental health and health perception) parameters. In addition, the interviews consisted of socio-demographic data elements. Clinical details regarding severity of prostatic disease and co-morbidity were obtained from the medical charts. RESULTS We found a correlation between postoperative change in symptom effect and in generic quality of life measures (r-0.11 to 0.20, p < 0.04). The postoperative decrease in the mean symptom effect score was 56% and 52% for severe and moderate preoperative levels, respectively. There was no decrease in the mean symptom effect score for the mild preoperative level (18% of these patients had postoperative deterioration). A secondary operation, and the combination of diabetes mellitus and poor activity level were risk factors for lack of improvement in patients with moderate preoperative symptom effects. We found that the impact of open prostatectomy on quality of life was similar to that of the closed technique after adjustment for patient attributes, except for those with an indwelling urinary catheter in whom an open operation was advantageous. CONCLUSIONS In patients with BPH and mild symptom effects, and in subgroups of patients with moderate symptom effects surgery should not be recommended. Based on short-term measures of quality of life there is no justification for a preference between open and closed operations.

The competing effects of disease states on quality of life of the elderly

During the period 1993–1994 we conducted a study in Israel on a national-based sample of 960 men to examine the relationships between urinary symptoms and various domains of quality of life (QoL). Regression analyses were performed for each of the eight SF-36 domains, separately for the entire population and for those without any co-morbidity. The dependent variable was the SF-36 domain scores. The independent variables included age, origin, education, employment and economic status, the degree of disturbance caused by urinary symptoms and the existence of co-morbidities. There was a significant difference between the entire population and the population without co-morbidities. In the entire population we found that severely bothersome urinary symptoms were related to scores on three QoL domains (social function, role–emotional and mental health) but there was no association with physical functioning and general health perceptions. In men without co-morbidity, urinary symptoms were substantially related to physical functioning and general health perceptions. These findings indicate that the relative weight of the impact of a symptom or disease on QoL domains is changed by the presence of other competing factors, such as co-morbidities or sociodemographic attributes.

Inconsistency of a model aimed at predicting bacteremia in hospitalized patients.

Clinical prediction rules can help physicians determine the necessity for blood cultures in specific patients and/or in whom empiric antibiotic treatment should be administered. Before adopting a prediction rule its validity must be evaluated in different settings. We revealed independent predictors of true bacteremia and developed a risk score based on them in one group of adult hospitalized patients (n = 474; derivation set). An attempt was made to validate this risk score in a second group of in-patients at the same hospital (n = 438; validation set). The derivation set included 540 blood culture episodes and the validation set 516. A blood culture episode was defined as one or more of all blood specimens withdrawn for culture from one patient over one 24 hour period. Independent multivariate predictors of true bacteremia were: temperature of 39 degrees C or higher, current immunosuppressive therapy, serum alkaline phosphatase > 100 IU and hospitalization in an intensive care unit. In the low risk group, defined by the absence of the said predictors, the rates of true bacteremia were 5.1 and 4.6% for the derivation and validation sets, respectively. As raised temperature is the main clinical feature guiding physicians to suspect bacteremia, we examined the probability of true bacteremia in patients with a temperature of less than 38 degrees C and found it to be 5.6% in the two sets. The model identified high risk subset patient groups demonstrating true bacteremia in 38% of all episodes in the derivation set and the comparatively low rate of 12.1% (p < 0.01) for the validation set.(ABSTRACT TRUNCATED AT 250 WORDS)

A national study of postoperative mortality associated with coronary artery bypass grafting in Israel

BACKGROUND Investigation of observed differences in outcomes among medical centers is of major interest to the medical community and the public and has a substantial impact on efforts to improve the quality of medical care. METHODS This study analyzed data from consecutive patients who underwent isolated coronary artery bypass grafting at 14 medical centers. Data included demographic and clinical information, comorbidity, cardiac catheterization results, and 30-day postoperative vitality status. Logistic regression analysis was used to identify variables associated with mortality. An outlier hospital was defined as one having an observed mortality outside the 95% confidence interval boundaries around the expected mortality rate calculated, given the patient risk factors. RESULTS The overall crude 30-day mortality rate for isolated coronary artery bypass grafting among the 4,835 patients in this study was 3.1%. The rate varied among centers, ranging from 0.85% to 7.05%. Predictors of 30-day mortality included advanced age, female sex, diabetes mellitus, poor left ventricular function, high creatinine level, high priority of operation, and three-vessel disease (with or without left main coronary artery disease). After adjustment for risk factors, two hospitals were defined as outliers. CONCLUSIONS The observed disparity in early mortality among patients undergoing coronary artery bypass grafting is not due solely to differences in case mix.

Use of a clustered model to identify factors affecting hospital length of stay.

Predictive models have been used to identify factors that may prolong hospital length of stay (LOS). However, because predictors of LOS are collinear, the proportion of variance associated with each factor in a multivariate stepwise regression model may not reflect its mathematical contribution in explaining LOS. In an attempt to model factor contribution to LOS more realistically, we evaluated a clinically based clustered model. This model uses classes of candidate predictors, that is, patient attributes, adverse events, treatment modality, and health provider identity. Clusters of variables are permitted to enter into the model in a theoretically based predetermined sequence, so that the additional contribution of each cluster of factors can be assessed while the contribution of preceding factors is preserved. The clustered model was tested and compared with a free stepwise multivariate analysis in a cohort of patients undergoing prostatectomy for benign prostatic hypertrophy. We found that both models explained a similar proportion of the variance in LOS (56%-57%). However, some important differences were evident. Prostate size, associated with 12% of the variance in the clustered model, was not an independent predictor in the free model. A higher proportion of variance was associated with process variables, such as treatment modality in the free model. We conclude that use of a clustered model may facilitate more realistic assessment of the relative contribution of factors to LOS.