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.

MS-CANE: a computer-aided instrument for neurological evaluation of patients with multiple sclerosis: enhanced reliability of expanded disability status scale (EDSS) assessment.

Kurtzke's EDSS remains the most widely-used measure for clinical evaluation of MS patients. However, several studies have demonstrated the limited reliability of this tool. We introduce a computerized instrument, MS-CANE (Multiple Sclerosis Computer-Aided Neurological Examination), for clinical evaluation and follow up of patients with multiple sclerosis (MS) and to compare its reliability to that of conventional Expanded Disability Status Scale (EDSS) assessment. We developed a computerized interactive instrument, based on the following principles: structured gathering of neurological findings, reduction of compound notions to their basic components, use of precise definitions, priority setting and automated calculations of EDSS and functional systems scores. An expert panel examined the consistency of MS-CANE with Kurtzke's specifications. To determine the effect of MS-CANE on the reliability of EDSS assessment, 56 MS patients underwent paired conventional EDSS and MS-CANE-based evaluations. The inter-observer agreement in both methods was determined and compared using the kappa statistic. The expert panel judged the tool to be compatible with the basic concepts of Kurtzke's EDSS. The use of MS-CANE increased the reliability of EDSS assessment: Kappa statistic was found to be 0.42 (i.e. moderate agreement) for conventional EDSS assessment versus 0.69 (i.e. substantial agreement) for MS-CANE (P=0.002). We conclude that the use of this tool may contribute towards a standardized and reliable assessment of EDSS. Within clinical trials, this could increase the power to detect effects, thus reducing trial duration and the cohort size required. Multiple Sclerosis (2000) 6 355 - 361

Sequential logistic models for 30 days mortality after CABG: pre-operative, intra-operative and post-operative experience--The Israeli CABG study (ISCAB). Three models for early mortality after CABG.

OBJECTIVES: The goal of this paper was to examine the added effect of operative and post-operative variables on 30 days mortality, in addition to patients' case-mix factors. SETTING AND DESIGN: A prospective study of 4835 patients, 95% of all Israeli patients who underwent coronary artery bypass grafting (CABG) in 1994. Information related to risk of death was collected at admission to hospital (preceding the operation), at time of the operation and in the immediate post-operative period. Deaths were independently ascertained. METHOD: Data collectors followed every patient from admission to discharge. Sequential logistic models were constructed for the 'case-mix', 'operative' and the 'post-operative' periods in chronological order. Each model incorporated and adjusted for the risk estimated at the previous point in time, by forcing individual risk scores. RESULTS: Significant pre-operative risk factors for 30 days mortality, in the case-mix model included mainly severity of illness characteristics, such as, left ventricular dysfunction and emergency admission, (c-statistic 78.8%). Model 2 (the 'operation' model) included in addition to the case-mix score, excessive duration of the operation per graft, bleeding, etc. (c-statistic 85.3%). The post-operative model showed the added effect of the post-operative factors such as low haemoglobin, additional surgery, and excessive time on respirator, (c-statistic 92.4%). CONCLUSIONS: The sequential analysis was an efficient method for updating patients' risk over time, where the number of events was small, relative to the number of risk factors. The addition of peri-operative factors increased significantly the predictive power of the model, adding clinical insights to the role of the hospital experience on 30 days mortality.

The bleeding risk and natural history of idiopathic thrombocytopenic purpura in patients with persistent low platelet counts.

BACKGROUND: No firm data are available on the natural history of idiopathic thrombocytopenic purpura (ITP) or on mortality rates or frequency of major bleeding episodes associated with this condition. The disease is thought to have a relatively benign course, despite the frequent occurrence of very low platelet counts. This prevailing conception often guides therapeutic decisions. OBJECTIVE: To estimate the bleeding risk of ITP involving persistent low platelet counts (<30 x 10(9)/L) and its impact on prognosis. DESIGN: Age-adjusted bleeding risk was derived from a pooled analysis of ITP clinical series based on a systematic literature search. The risk estimate was incorporated into a Markov model to determine its impact on prognosis. RESULTS: Seventeen case series complied with inclusion criteria, including 1,817 patients with ITP. There were 49 cases of fatal hemorrhage over an estimated 1,258 to 3,023 patient-years at risk. The rate of fatal hemorrhage before age adjustment was estimated at between 0.0162 and 0.0389 cases per patient-year. Age-adjusted rates were 0.004, 0.012, and 0.130 cases per patient-year for age groups younger than 40, 40 to 60, and older than 60 years, respectively. Predicted 5-year mortality rates ranged from 2.2% for patients younger than 40 years to 47.8% for those older than 60 years. A 30-year-old woman remaining thrombocytopenic due to ITP was predicted to lose 20.4 years (14.9 quality-adjusted life years) of her potential life expectancy. At age 70, predicted loss was 9.4 years (5.0 quality-adjusted life years). CONCLUSIONS: Idiopathic thrombocytopenic purpura with persistent low platelet counts carries a grave prognosis. Therefore, an active therapeutic approach in the clinical management of affected patients should be considered. In view of the significant potential implications of the model results, we call for initiating a well-designed prospective inception cohort study of patients with ITP.

Factors associated with health indicators in patients undergoing coronary artery bypass surgery.

BACKGROUND: The main goals of coronary artery bypass graft (CABG) surgery for most patients are to relieve angina, to improve functional capacity, to return to work, and to improve health. A limited amount of information is available regarding the various attributes that are associated with achieving these goals. STUDY OBJECTIVES: To investigate different patient attributes affecting these outcomes. DESIGN: Prospective data collection. SETTING: Fourteen medical centers that perform CABG surgery in Israel. PATIENTS: The 4,012 patients who underwent CABG surgery during 1994. MEASUREMENTS: Trained nurses collected data using structured questionnaires prior to and 4 to 5 months after the operation. Using logistic regression, four risk models were created to the following health indicators: recurrence of angina, functional capacity, return to work, and perception of health. Candidate variables were sociodemographic details, major comorbidities, risk factors for cardiac disease, and severity of cardiac disease. RESULTS: The mean age of the patients was 63.8 years old, 79.3% were men, 59.9% were elective operations, and left main disease was found in 17.3%. Multivariate logistic regression revealed that the variables that significantly contributed to three or more of the models were Sephardic Jewish origin, female gender, left ventricular dysfunction, and diabetes mellitus. CONCLUSIONS: There is a similarity between risk factors of various health indicators in CABG surgery patients. Thus, it is possible to define a population at high risk that may not benefit from the procedure.

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.

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

Information is lacking about the public's 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.

Comparing medical centers treating hip fractures in the elderly: the importance of multi-outcome measurements.

The objective of this study was to assess the merit of multi-outcome measurements on the evaluation of quality of care, comparing different health care providers. We performed a cross-sectional study in 3 medical centers. Three hundred three patients undergoing surgical repair of traumatic femoral neck fracture were included. Trained nurses gathered data by patient and proxy interview and by chart abstraction. Multivariate analysis was performed to obtain an explanatory model for each outcome. Then, the additional contribution of each of the centers to the explanatory power of the model was examined. The outcomes were mortality, functional capacity, post-operative complications, and length of stay. Explanatory variables included were sociodemographic details, comorbidity indices, preoperative functional capacity, depression, and cognition. The results demonstrated that center A was a "good" outlier for mortality rate but, in contrast, was a "bad" outlier for complication rate and length of stay. Center B was a "bad" outlier for functional capacity but a "good" outlier for length of stay. We conclude that outcome studies for quality assurance programs should include all relevant outcomes, as the assumption that one major outcome may be representative for quality of care assessment may be misleading.

The competing effects of disease states on quality of life of the elderly: the case of urinary symptoms in men.

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.

A national study of postoperative mortality associated with coronary artery bypass grafting in Israel. ISCAB Consortium. Israel Coronary Artery Bypass Study.

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.

Variation in mortality among seven hemodialysis centers as a quality indicator.

OBJECTIVES: To identify patient attributes that were associated with increased mortality; variables that were associated with process of care that were correlated with mortality; and outlier centers after adjustment for patient attributes. DESIGN: Standard interviews were conducted by trained nurses with all patients. Detailed information regarding primary renal diagnosis, comorbidity, and results of laboratory tests were obtained from the medical charts. The vital status of the patients was obtained from the records of each of the centers. We used the Cox hazard method to identify variables that correlated with a 1-year mortality. Centers with observed mortality exceeding the 95% confidence interval (CI95) of the expected probability of death were marked as outliers. SETTING: Seven dialysis centers located in large teaching hospitals in Israel. PATIENTS: The current study included patients > 16 years of age who had undergone hemodialysis > 4 weeks prior to the day of data collection. RESULTS: The study included 564 patients. Significant differences were found in patient demographics and process variables among the centers. The following variables correlated with mortality; diabetes (odds ratio [OR], 2.03; CI95, 1.28-3.21); ischemic heart disease (OR, 2.2; CI95, 1.39-3.49); each year of age (OR, 1.04; CI95, 1.02-1.06); each 1 g% of albumin (OR, 0.51; CI95, 0.30-0.86). The average observed mortality in all centers was 17.4%. After adjustment for casemix, one center showed excess mortality (24% observed compared to 15% expected after adjustment for patient attributes; CI95, 6.2-23.7). CONCLUSIONS: The ability to compare mortality rates among dialysis centers to detect possible quality outliers depends on thorough consideration of patient attributes and random variation.

Comparison of factors associated with 30-day mortality after coronary artery bypass grafting in patients with versus without diabetes mellitus. Israeli Coronary Artery Bypass (ISCAB) Study Consortium.

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 importance of laboratory data for comparing outcomes and detecting 'outlier' wards in the treatment of patients with pneumonia.

OBJECTIVES: To evaluate whether routine laboratory data can improve the ability to compare risk-adjusted outcomes of different medical wards, and to detect 'outlier' wards with significantly better or worse outcome. METHODS: Patient data were taken from the Combined Patient Database Systematic Management and Research Tool, a database created by merging different computerized sources at a tertiary care hospital. All patients admitted to internal wards with the diagnosis of pneumonia during the years 1991-1995 were included (n = 2734). The outcome variable was mortality 30 days post-admission. We used three comorbidity measures based on ICD-9-CM codes as possible predictors of mortality: secondary diagnoses; the Health Care Financing Administration severity index; and the Charlson comorbidity index. Models were created using logistic regression. To each model, laboratory data gathered in the first 48 hours after admission were added. To identify 'outlier' services we determined whether the patients' ward was an independent predictor of mortality. The area under the receiver operator curve (ROC) of the models was used for comparisons. RESULTS: The area under the ROC was 0.65-0.72 for the models based on age and comorbid diagnoses. The addition of laboratory data improved markedly the discriminatory ability of each of the models, as reflected by an increase in the area under the ROC to 0.83-0.84. An 'outlier' ward with a higher risk-adjusted mortality rate was identified only by the models that included laboratory data. CONCLUSION: Basic, automated, routinely gathered laboratory data added significantly to the discriminatory power of risk models based on administrative data with abstracted diagnoses. Addition of laboratory data improved the ability to identify providers with possible exceptional quality of care.

Underutilization of health services among patients with urinary symptoms: results of a population-based survey in Israel.

BACKGROUND: Although there is firm evidence concerning the relatively-high rates of overutilization of prostate surgery among elderly men, only minimal efforts have been made to evaluate the existence and extent of underutilization. This assessment, accomplished by our study, may have a significant impact on health services planning and budgeting. METHODS: The study population comprised a nationwide representative sample of 960 Israeli men, aged between 45 and 75 years. Data were accumulated by personal interviews conducted at the homes of the individuals by trained staff. The questions included in the questionnaire aimed at describing the sociodemographic and clinical status. The responses to questions regarding male urinary symptoms were obtained by personal reports. RESULTS: Forty-three percent of the subjects reported having experienced urinary symptoms, but only 4.6% were severely bothered by the symptoms on a daily basis, and 8.9% were moderately bothered. Only 55.4% of patients with bothersome urinary symptoms visited their general practitioners, while only 39.7% were referred to a urologist because of their complaints. CONCLUSIONS: Elderly men bothered by urinary symptoms frequently do not seek health care. An educational program regarding the potential benefit of medical interventions for benign prostatic hypertrophy may significantly improve their quality of life.

Differences in quality of life among patients receiving dialysis replacement therapy at seven medical centers.

The purpose of this study is to investigate the variations in quality of life (QOL) among patients with end-stage renal disease (ESRD) who are receiving replacement therapy in several dialysis centers. This observational study includes interviews with nurses and data extraction from medical charts for all 680 adults who had been on dialysis therapy for more than 4 weeks in seven dialysis centers. By using multivariate analysis, we generated a model to explain the variance in QOL as measured by the QL index score (developed by Spitzer et al., J Chronic Dis 1981; 34:585-597) among patients pooled from all centers. The expected mean QL index score and 95% confidence interval were computed for each dialysis center. Centers with observed mean QL index scores outside of the expected confidence range were marked as possible outliers. We found the following patient attributes to be independently associated with QOL: age, education, occupation, and certain comorbidities (e.g., diabetes, stroke). After adjustment for case mix, we could identify four outlier centers. After further adjustment for albumin in serum, a possible process indicator, two centers were no longer considered as outliers. These findings indicate that the variance in QOL of ESRD patients at different centers is not entirely explained by known case-mix factors. Further research should explore whether such variations are related to dissimilarity in the process of care at different centers.

The contribution of personal rating to the clinimetric functioning of a generic quality of life instrument.

We assessed the contribution to measurement properties of weighting the items of a generic quality of life (QOL) index. Data were acquired from an observational study on QOL of 675 patients with end-stage renal disease (ESRD). As an outcome measure we used the Spitzer QL-index. We compared scores on this generic index to those constructed using weighting schemes based on personal rating of each of the items included in the generic index. We found that the weighted schemes were not superior to the nonweighted with regard to: (a) Their ability to discriminate between diseased and nondiseased patients with five major comorbidities, and among patients reporting five different categories of global assessment of QOL, (b) Their responsiveness, i.e., identifying changes in QOL over a year and (c) Their predictive ability for one year mortality. We conclude that weighting by personal rating added no marginal benefit to a generic, nonweighted QOL instrument in ESRD patients.

Two-dimensional outcome analysis as a guide for quality assurance of prostatectomy.

PURPOSE: To find outlier centers in different aspects of quality of care by comparing two different outcomes and adjusting to case mix in benign prostatic hypertrophy (BPH) patients undergoing prostatectomy. MATERIALS AND METHODS: An observational study including 537 consecutive patients undergoing prostatectomy for BPH in three medical centers in Israel between 1991 and 1992. Data were collected from medical charts and by a structured interview. Outcomes examined included immediate surgical complications and postoperative symptom effect level. Regression analysis was employed to adjust for case mix and to determine the additional contribution of medical centers. RESULTS: We found significant variability among centers in crude symptom effect, but not after case mix adjustment. An outlier was detected in both the crude and case mix-adjusted urological complications. CONCLUSIONS: Centers may differ with various outcomes. This may reflect variability in different levels of performance within different aspects of the process of care in prostatectomy procedures.

Medical patients assessment protocol: a tool for evaluating the appropriateness of utilizing hospital-stay days for acute medical patients; development, reliability and applications.

An attempt was made to formulate a tool that, when compared to the appropriateness evaluation protocol (AEP) used for evaluating the utilization of hospital services for medical patients, would be an improvement. To establish this, a four-phase project was evolved, which included: (a) taxonomy definition of medical and nonmedical reasons for acute-care hospital bed utilization for a day of care, (b) use of the preliminary protocol by trained nurses to extend the range of clinical conditions included, (c) independent review of the protocol by three senior physicians, and (d) comparative interrater reliability and feasibility study between the new instrument-the medical patients assessment protocol (MPAP) and the AEP. We found the MPAP to have a higher inter-rater reliability than the AEP (kappa = 0.94 and 0.78, respectively), to be more clinically oriented, more comprehensive, and similar to the AEP regarding the time required for investigation of cases. Therefore, we recommend the use of the MPAP for management and quality control of medical hospitalized patients.