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Biomedical subjects

S Schneeweiss

Publications and source records attributed to S Schneeweiss.

At least 19 recordsLinked to original sources
PubMed2006

Patterns of cardiovascular risk in rheumatoid arthritis.

BACKGROUND: Although it is known that rheumatoid arthritis is associated with an increased risk of cardiovascular disease (CVD), the pattern of this risk is not clear. This study investigated the relative risk of myocardial infarction, stroke and CVD mortality in adults with rheumatoid arthritis compared with adults without rheumatoid arthritis across age groups, sex and prior CVD event status. METHODS: We conducted a cohort study among all residents aged >or=18 years residing in British Columbia between 1999 and 2003. Residents who had visited the doctor at least thrice for rheumatoid arthritis (International Classification of Disease = 714) were considered to have rheumatoid arthritis. A non-rheumatoid arthritis cohort was matched to the rheumatoid arthritis cohort by age, sex and start of follow-up. The primary composite end point was a hospital admission for myocardial infarction, stroke or CVD mortality. RESULTS: 25 385 adults who had at least three diagnoses for rheumatoid arthritis during the study period were identified. During the 5-year study period, 375 patients with rheumatoid arthritis had a hospital admission for myocardial infarction, 363 had a hospitalisation for stroke, 437 died from cardiovascular causes and 1042 had one of these outcomes. The rate ratio for a CVD event in patients with rheumatoid arthritis was 1.6 (95% confidence interval (CI) 1.5 to 1.7), and the rate difference was 5.7 (95% CI 4.9 to 6.4) per 1000 person-years. The rate ratio decreased with age, from 3.3 in patients aged 18-39 years to 1.6 in those aged >or=75 years. However, the rate difference was 1.2 per 1000 person-years in the youngest age group and increased to 19.7 per 1000 person-years in those aged >or=75 years. Among patients with a prior CVD event, the rate ratios and rate differences were not increased in rheumatoid arthritis. CONCLUSIONS: This study confirms that rheumatoid arthritis is a risk factor for CVD events and shows that the rate ratio for CVD events among subjects with rheumatoid arthritis is highest in young adults and those without known prior CVD events. However, in absolute terms, the difference in event rates is highest in older adults.

Adolescent↗
PubMed2004

Incidence and predictors for chronicity of headache in patients with episodic migraine.

The authors followed 532 consecutive patients with episodic migraine (<15 days/month) for 1 year. Sixty-four patients (14%) developed chronic headache (>/=15 days/month). The odds ratios for developing CH were 20.1 (95% CI 5.7 to 71.5) comparing patients with a "critical" (10 to 14 days/month) vs "low" (0 to 4 days/month) and 6.2 (95% CI 1.7 to 26.6) in patients with an "intermediate" (6 to 9 days/month) vs "low" headache frequency and 19.4 (95% CI 8.7 to 43.2) comparing patients with and without medication overuse.

Adult↗
PubMed2003

Frequency and predictors of drug therapy interruptions after hospital discharge under physician drug budgets in Germany.

OBJECTIVE: We sought to study how frequently prescription drug therapy at hospital discharge was discontinued or changed by general practitioners under physician drug budgets in Germany and explore reasons and predictors for such discontinuations. METHODS: This cohort study was part of a larger project on clinical outcomes of acute hospital care in patients with 5 groups of medical diagnoses, including conditions of the heart, lung and brain, gastroduodenal ulcer disease and diabetes. Patients entered the study cohort at hospital admission and were followed throughout their stay until they had their first encounter with a primary care physician responsible for follow-up treatment after hospital discharge. Nurse practitioners and physicians assessed patient characteristics at admission and discharge. A 1-page questionnaire on continuity of care, including drug therapy, was provided to primary care physicians at the first patient encounter. The primary study endpoint was discontinuation of drug therapy by the primary care physician. Data were analyzed by multivariate logistic regression. RESULTS: A total of 3,267 patients in 22 primary care hospitals were eligible for the study. Standardized questionnaires on continuation of drug therapy were returned by 890 patients (27%); 846 patients (95%) used prescription drugs at discharge. Of those, drug therapy was interrupted in 122 (14%). Reasons for discontinuations included excessive costs of drugs in 66 patients (54%), excessive number of drugs prescribed (32, 26%) and differences in judgment on the clinical appropriateness of a drug (23, 19%). In a multivariate logistic regression, gastroduodenal ulcer disease was a significant predictor for discontinuation (OR = 3.1; 95% CI 1.5 - 6.5). Discontinuation tended to be more likely in older patients (69 - 76 years vs. < or = 58: OR = 2.0; 1.0 - 3.9) but slightly less likely in male patients (OR = 0.7; 0.4 - 1.1). CONCLUSION: Discontinuation of drug therapy after hospital discharge is common. The high costs of prescription drugs were the most common reason. Elderly patients seem to be particularly affected.

Adult↗
PubMed2001

Performance of comorbidity scores to control for confounding in epidemiologic studies using claims data.

Comorbidity is an important confounder in epidemiologic studies. The authors compared the predictive performance of comorbidity scores for use in epidemiologic research with administrative databases. Study participants were British Columbia, Canada, residents aged >or=65 years who received angiotensin-converting enzyme inhibitors or calcium channel blockers at least once during the observation period. Six scores were computed for all 141,161 participants during the baseline year (1995-1996). Endpoints were death and health care utilization during a 12-month follow-up (1996-1997). Performance was measured by using the c statistic ranging from 0.5 for chance prediction of outcome to 1.0 for perfect prediction. In logistic regression models controlling for age and gender, four scores based on the International Classification of Diseases, Ninth Revision (ICD-9) generally performed better at predicting 1-year mortality (c = 0.771, c = 0.768, c = 0.745, c = 0.745) than medication-based Chronic Disease Score (CDS)-1 and CDS-2 (c = 0.738, c = 0.718). Number of distinct medications used was the best predictor of future physician visits (R(2) = 0.121) and expenditures (R(2) = 0.128) and a good predictor of mortality (c = 0.745). Combining ICD-9 and medication-based scores improved the c statistics (1.7% and 6.2%, respectively) for predicting mortality. Generalizability of results may be limited to an elderly, predominantly White population with equal access to state-funded health care.

Aged↗
PubMed2001

[An update of the German version of AEP (Appropriateness Evaluation Protocol): metric properties and practical experiences].

The development of a German version of the Appropriateness Evaluation Protocol (AEP) allows for the first time the evaluation of hospital admissions and bed days in Germany. The instrument is based on international experience and has been adopted in cooperation with acknowledged members of German surgical and medical societies. The AEP showed excellent reliability in general internal medicine as well as in surgery. The validity is comparable to international studies, although further research is necessary. Approximately 90% of surgical cases could be evaluated according to the criteria of the AEP; the remaining patients were evaluated using the "override option". The majority of inappropriate care is due to poor documentation in medical records and management deficiencies during inpatient care.

Geriatrics↗
PubMed2001

On the evaluation of drug benefits policy changes with longitudinal claims data: the policy maker's versus the clinician's perspective.

Cost containment in pharmaceutical-benefit plans are often controversially debated for their potential of unintended consequences on health and overall expenditures. Thorough evaluations are needed but hypotheses and design considerations are complex. Our objective is to provide a structured framework for the evaluation of drug-benefit changes using longitudinal claims data. Differential cost sharing (DCS) will serve as a recent example. Benefit-plan managers are mainly interested in the overall performance of their plan. In a policy model, any observed policy-related effects may be compared with what would have happened had the intervention not been implemented by extrapolating the pre-policy trend from the same patients. These estimates will reflect the global consequences of the policy maker's decision. However, such estimates represent summary effects of benefits and harms, separately identifiable in those complying with the intended policy and those not complying. Results from a policy model apply only to a specific policy implementation and tend to underestimate effects when non-compliance is high. Clinical-decision makers and patients, by contrast, are interested in the consequences of patients' actual compliance to the policy. A clinical model assesses the effects of DCS depending on the actual treatment in contrast to the treatment intended by the policy. However, this model must sometimes make, unprovable assumptions about the appropriate control of selection factors. In conclusion, both policy and clinical models should be tested with a clear understanding of their perspectives, hypotheses, and interpretations, using quasi-experimental time-series designs to evaluate the effects of drug cost-containment policies.

Attitude of Health Personnel↗
PubMed2001

First results from an intensified monitoring system to estimate drug related hospital admissions.

AIMS: An intensified monitoring system was set up to identify drug related hospital admissions and estimate population-based incidences for commonly prescribed medications. METHODS: Pharmacovigilance-centres systematically screened nonelective admissions to emergency rooms or departments of internal medicine for drug related hospitalizations (DRH). Clinical pharmacologists used standardized causality assessment. Service areas of each acute care hospital were defined by 5 digit postal codes that covered 60% of all admissions. Drug dispensing information was available through claims processed by regional pharmacy computing centres. Quarterly incidences were estimated by dividing the number of events by the number of treated patients. RESULTS: 435 DRHs were reported during five quarters. The incidence of ADRs leading to admissions varied for specific drug groups from 1.5/10 000 treated patients to 24/10 000. Quarterly variation of incidences was moderate except for insulin and calcium antagonists. 95% confidence intervals overlap for all quarters within each group. Incidences are sensitive to changes in the definition of the source population. CONCLUSIONS: Our pharmacovigilance monitoring system allows comparisons of population-based incidences of drug-related hospitalizations among drugs and over time. It provides important information for risk management and monitoring outcomes of pharmaceutical quality management programmes.

Adverse Drug Reaction Reporting Systems↗
PubMed2001

[Patient-centered evaluation of the health status in a longitudinal quality management system in the hospital].

OBJECTIVE: The objective was to assess the value of self-reported health status as an indicator of outcomes of acute hospital care, to identify potential practical limitations, and develop strategies for future applications. METHODS: 180 patients from 4 acute care hospitals in Germany participated in a comprehensive and longitudinal assessment of outcome of care in general internal medicine between 8/1/99 and 10/31/99. Self-administered SF-36 surveys were completed at admission and 4 weeks after discharge. Additionally, nurses and physicians answered questions regarding the patients' health status. Linear relations between health status assessments were quantified as correlation coefficients. Odds ratios (OR) and 95% confidence limits from multivariate logistic regression models were reported for predictors of non-returned questionnaires. RESULTS: 33% of SF-36 surveys handed out at discharge were returned. Patients with impairments and referred patients were more likely not to return the survey (OR = 1.3 [1.09; 1.66] and OR = 3.7 [1.37; 9.87]). The linear relation of SF-36 and SF-12 scores in the same patients were r = 0.95 [0.91; 0.97] for physical health and r = 0.91 [0.85; 0.94] for mental health. Physicians and nurses moderately agreed in their assessment of patients' health (r = 0.38 [0.22; 0.52]) but both professional groups showed poor agreement with self-reported health (r = 0.15 [-0.08; 0.36] and r = -0.01 [-0.23; 0.21]). CONCLUSIONS: 1. Self-reported health status should be considered in the assessment of outcomes of acute care as a dimension that is to some extent independent of health status assessment by professionals, 2. shorter instruments, i.e., the SF-12, can be used instead of the SF-36, 3. a self-reported health status assessment is feasible 4 weeks after discharge, and 4. patients with multiple impairments or those who are transferred should get specific support in the completion of questionnaires to increase response or to receive at least minimal information about their health status.

Aged↗
PubMed2001

Causation of bias: the episcope.

A risk ratio or difference from a meta-analysis is as many as ten steps away from the unobservable causal risk ratios and differences in target populations. The steps are like lenses, filters, or other fallible components of the epidemiologist's "telescope" for observing populations. Each step is another domain where different biases can be caused. How biases combine across domains in the production of epidemiologic evidence can be quickly explained to nonepidemiologists by using a sequence of causal arrow diagrams with easy notation: (a) agent of interest, (b) background risk factors, (c) correlated causes, (d) diagnosis, (e) exposure measurement, (f) filing of data, (g) grouping of cohorts, (h) harvesting of cases and controls, (i) interpretations of investigators, (j) judgments of journals, and (k) knowledge of meta-analysts. For epidemiologists, this article serves as a review of ideas about confounding, information bias, and selection bias and underscores the need for routinely analyzing the sensitivity of study findings to multiple hypothesized biases.

Bias↗
PubMed2001

A case-control study of the effect of infant feeding on celiac disease.

AIMS: The aim of this study was to investigate the association between the duration of breast-feeding and the age at the first gluten introduction into the infant diet and the incidence and age at onset of celiac disease. METHODS: In a case-control study, 143 children with celiac disease and 137 randomly recruited gender- and age-matched control children were administered a standardized questionnaire. Multivariate-adjusted odds ratios (OR) as estimates of the relative risk and corresponding 95% confidence intervals (95% CI) were calculated. RESULTS: The risk of developing celiac disease decreased significantly by 63% for children breast-fed for more than 2 months (OR 0.37, 95% CI 0.21-0.64) as compared with children breast-fed for 2 months or less. The age at first gluten introduction had no significant influence on the incidence of celiac disease (OR 0.72, 95% CI 0.29-1.79 comparing first gluten introduction into infant diet >3 months vs. < or =3 months). CONCLUSIONS: A significant protective effect on the incidence of celiac disease was suggested by the duration of breast-feeding (partial breast-feeding as well as exclusive breast-feeding). The data did not support an influence of the age at first dietary gluten exposure on the incidence of celiac disease. However, the age at first gluten exposure appeared to affect the age at onset of symptoms.

Age of Onset↗
PubMed2000

[Evaluation of the appropriateness of hospital care in internal medicine. Reliability of a German adaptation of the procedure].

BACKGROUND AND OBJECTIVE: The evaluation of the appropriateness of hospital admissions and hospital stays has become an increasingly important issue in Germany. Evaluations by the German Physicians Review Organizations (MDS, MDK) demonstrated the need for a standardized, valid and reliable assessment tool for inappropriate hospital use. Objective of this study was to test the reliability of a German adaptation of the "Appropriateness Evaluation Protocol" (AEP). PATIENTS AND METHODS: From the 2317 admissions to medical wards of a teaching hospital in Hessia in 1997 we randomly selected 52 patients to test the inter-rater-reliability (54% female, mean age = 66 years +/- 18). Another 49 patients were randomly selected to test the intra-rater-reliability of the AEP (53% female, mean age = 61 years +/- 20). We estimated general agreement, specific agreement and Kappa statistics for the agreement of the evaluation of hospital admissions and hospital days. 95% confidence intervals were reported. RESULTS: The German adaptation of the AEP showed an inter-rater-agreement of 92% (88-96%) for hospital admissions and 76% (73-80%) for hospital days. Correspondingly, we observed an intra-rater-agreement of 96% (88-100%) for hospital admissions and 93% (91-95%) for hospital days. The high agreement was independent of the length of hospital stay and independent of the proportion of inappropriate hospital days. CONCLUSION: A standard instrument for the assessment of the appropriateness of hospital care with known metric properties may be useful for quality management in hospitals and provide competitive advantages in a consolidating health care market. The AEP could be such an instrument.

Aged↗
PubMed2000

[Reproducibility of a German scale for assessing the need for inpatient treatment in surgery].

During the past years, the assessment of the appropriateness of hospital utilization has become increasingly important in the German health care system. Previous evaluations by regional review organizations in several states demonstrated the need for a standardized, reliable, and valid instrument to evaluate the appropriateness of inpatient care. Objective of the study is to test the reliability of a German adaptation of the "Appropriateness Evaluation Protocol" (AEP). Among all 2672 admissions from the department of surgery of a regional medical center during one calendar year, 54 patients were randomly selected to evaluate the inter-rater reliability and 51 patients to test intra-rater reliability. Overall agreement, specific agreement and Kappa statistics were estimated for every hospital admissions and all consecutive hospital days. The German AEP showed an inter-rater agreement of 74% (62-86%) for hospital admissions (Kappa = 0.44) and 84% (79%-88%) for all hospital days (K = 0.55). Intra-rater reliability was 88% (79%-97%) for hospital admissions (K = 0.60) and 88% (85%-92%) for all hospital days (K = 0.70). The observed agreement is independent of length of hospital stay and proportion of appropriate days. A standardized instrument with known metric properties is essential for quality management in hospitals to prepare for an increasingly consolidating health care market in Germany. The German AEP is a reliable instrument, which will allow to identify inefficiencies in the management of surgical inpatients.

Adult↗
PubMed2000

Sensitivity analysis of the diagnostic value of endoscopies in cross-sectional studies in the absence of a gold standard.

OBJECTIVES: The evaluation of the diagnostic value of endoscopic procedures usually lacks a gold standard when performed in cross-sectional studies. The objective is to demonstrate an easily applicable method to assess the possible range of sensitivity, specificity, and predictive values of endoscopic procedures in the absence of a gold standard method. METHODS: Data from a study of 328 endoscopies comparing two different methods to diagnose superficial bladder cancer were used as a numerical example. Both endoscopic procedures were performed in the same patients in one session. Under the assumption of a systematic misclassification process, a model to correct sensitivity estimates is developed. RESULTS: The lowest possible sensitivity estimate for a new fluorescence endoscopy technique (FE) was 78%, the maximum 97.5%. Depending on realistic assumptions made upon the misclassification, a reasonable estimate for sensitivity was 93.4% (95% confidence interval [CI]: 90%-97.3%) for the FE technique. The sensitivity of the traditional white-light endoscopy method ranged from 47.2% to 53%, with a reasonable estimate of 46.7% (95% CI: 39.4%-54.3%). CONCLUSIONS: This method to determine the theoretically possible range of sensitivity estimates in endoscopic procedures is helpful in cross-sectional studies with a missing gold standard method. It is easily applicable for a variety of endoscopic procedures, including upper and lower gastro-intestinal tract, urogenital tract, or diagnostic laparoscopic surgery.

Aminolevulinic Acid↗
PubMed2000

[Corroboration of concurrent assessment of inappropriate hospitalization with retrospective evaluation based on patient records].

BACKGROUND AND PURPOSE: Since the availability of a German adaptation of the "appropriateness Evaluation Protocol" (AEP) for hospital utilization review, physicians and health care managers were concerned about a potential overestimation of the extent of inappropriate hospital use in a retrospective assessment. The objective was to assess the agreement of concurrent and retrospective assessment of inappropriate hospital use. METHODS: The appropriateness of 42 admissions to surgical wards in a teaching hospital was tested concurrent to the admission. In 25 hospitalized patients the appropriateness of hospital days was assessed. Results were compared with the retrospective testing of the same patients after three months. RESULTS: Agreement between concurrent and retrospective assessment within the same reviewer was 86% of admissions (95% CI = 75%-96%) and 96% of hospital days (88%-100%). Kappa showed values of 0.85 and 0.78, which can be described as excellent. A comparison of two different reviewers, one testing concurrently, the other retrospectively showed agreements of 86% and 90%. The proportion of inappropriate days was the same in both designs. CONCLUSIONS: The results refute prior concerns that a retrospective assessment of the appropriateness of hospital use is impossible because in a retrospective design important clinical information would remain unconsidered or clinical information not yet available at that time would be used for the evaluation. The possibility of an incorrect assessment due to a retrospective design is within the variability inherent to the instrument. Despite the strong agreement, the small sample of surgical patient limits the generalizability of results.

Concurrent Review↗
PubMed2000

Use of comorbidity scores for control of confounding in studies using administrative databases.

BACKGROUND: Comorbidity scores are increasingly used to reduce potential confounding in epidemiological research. Our objective was to compare metrical and practical properties of published comorbidity scores for use in epidemiological research with administrative databases. METHODS: The literature was searched for studies of the validity of comorbidity scores as predictors of mortality and health service use, as measured by change in the area under the receiver operating characteristic (ROC) curve for dichotomous outcomes, and change in R(2) for continuous outcomes. RESULTS: Six scores were identified, including four versions of the Charlson Index (CI) which use either the three-digit International Classification of Diseases, Ninth Revision (ICD-9) or the full ICD-9-CM (clinical modification) code, and two versions of the Chronic Disease Score (CDS) which used outpatient pharmacy records. Depending on the population and exposure under study, predictive validities varied between c = 0.64 and c = 0.77 for in-hospital or 30-day mortality. This is only a slight improvement over age adjustment. In one study the simple measure 'number of diagnoses' outperformed the CI (c = 0.73 versus c = 0.65). Proprietary scores like Ambulatory Diagnosis Groups and Patient Management Categories do not necessarily perform better in predicting mortality. Comorbidity indices are susceptible to a variety of coding errors. CONCLUSIONS: Comorbidity scores, particularly the CDS or D'Hoore's CI based on three-digit ICD-9 codes, may be useful in exploratory data analysis. However, residual confounding by comorbidity is inevitable, given how these scores are derived. How much residual confounding usually remains is something that future studies of comorbidity scores should examine. In any given study, better control for confounding can be achieved by deriving study-specific weights, to aggregate comorbidities into groups with similar relative risks of the outcomes of interest.

Comorbidity↗
PubMed2000

Anorexigens and pulmonary hypertension in the United States: results from the surveillance of North American pulmonary hypertension.

BACKGROUND: The use of appetite suppressants in Europe has been associated with the development of primary pulmonary hypertension (PPH). Recently, fenfluramine appetite suppressants became widely used in the United States but were withdrawn in September 1997 because of concerns over adverse effects. MATERIALS AND METHODS: We conducted a prospective surveillance study on patients diagnosed with pulmonary hypertension at 12 large referral centers in North America. Data collected on patients seen from September 1, 1996, to December 31, 1997, included the cause of the pulmonary hypertension and its severity. Patients with no identifiable cause of pulmonary hypertension were classed as PPH. A history of drug exposure also was taken with special attention on the use of antidepressants, anorexigens, and amphetamines. RESULTS: Five hundred seventy-nine patients were studied, 205 with PPH and 374 with pulmonary hypertension from other causes (secondary pulmonary hypertension [SPH]). The use of anorexigens was common in both groups. However, of the medications surveyed, only the fenfluramines had a significant preferential association with PPH as compared with SPH (adjusted odds ratio for use > 6 months, 7.5; 95% confidence interval, 1.7 to 32.4). The association was stronger with longer duration of use when compared to shorter duration of use and was more pronounced in recent users than in remote users. An unexpectedly high (11.4%) number of patients with SPH had used anorexigens. CONCLUSION: The magnitude of the association with PPH, the increase of association with increasing duration of use, and the specificity for fenfluramines are consistent with previous studies indicating that fenfluramines are causally related to PPH. The high prevalence of anorexigen use in patients with SPH also raises the possibility that these drugs precipitate pulmonary hypertension in patients with underlying conditions associated with SPH.

Adult↗