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Results for “Propensity Score”

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PubMed2000

[Comparative epidemiological study in patients with rheumatic diseases illustrated in a example of a treatment with non-steroidal anti- inflammatory drugs versus an oral enzyme combination preparation].

To establish the safety and efficacy of an oral enzyme-combination product (OE; Phlogenzym, containing trypsin, bromelain and rutin) in the treatment of rheumatic diseases a retrolective cohort study with parallel groups was undertaken as an epidemiological study, in which the enzyme combination was compared with non steroidal anti-inflammatory drugs (NSAID). Data of 3326 patients treated for rheumatic diseases between January 1993 and the end of March 1995 were registered by 380 physicians. From the patient file age, gender, indication for treatment (diagnostic group), anamnestic data (especially pre-treatment), complaints at the beginning and end of treatment, treatment duration, prescribed drugs (OE, NSAID), additional treatment and adverse events were transferred into case report forms (CRFs). The quality of the data was monitored and additionally checked by internal and external quality audits. Included in the efficacy analysis were 2139 patients which were treated either only with OE or only with NSAID and could be classified unambiguously into one of the following diagnostic groups: joint diseases, spinal diseases, rheumatic soft tissue diseases. As clinically relevant and reliably evaluable criterion freedom from rheumatic complaints at the end of treatment was considered. For evaluation of safety the documented adverse events of all patients were considered. Two thirds of the OE patients received the recommended dose of 6 tablets/day, taken for 23 to 35 days. The respective mean values for NSAID patients were 16 to 25 days, and the patients were treated with the recommended symptomatically effective doses of NSAID. As the allocation of the compared treatment options (OE or NSAID) to the patients was not randomized, a mixing of treatment effects with other factors cannot be excluded. For adjustment of these confounding factors two methods were applied: a) logistic regression of the relative ratio of the main criterion and all confounding factors and b) stratification of data according to the propensity score i.e. the probability of a treatment with OE. Both methods yielded similar results: A 50% higher success rate can be expected in total for OE than for NSAID at comparable initial and treatment situations (95% confidence interval with logistic regression = 1.218-1.96, with stratification according to propensity score = 1.16-1.84). As significant negative indicators for response age over 50 years, pre-treatment with antirheumatic or analgetic drugs, treatment duration more than 30 days and joint diseases or fibromyalgias could be revealed. Since there was no interaction between these indicators and the type of treatment also in patients presenting with these indicators a treatment success (freedom from symptoms) with OE can be expected with a higher probability than with NSAID. OE were well tolerated showing much less adverse events when compared with conventional doses of NSAID.

Adult↗

PubMed2003

Does prior transfusion worsen outcomes from infection in surgical patients?

BACKGROUND: Controversy continues to exist regarding the immunomodulatory effects of cellular blood transfusions in the fields of oncology, transplantation, and infectious diseases. Numerous studies have correlated transfusion with hospital-acquired infection, but the impact of transfusion on infection-related mortality has not been addressed. The objective of this study was to determine the effect of transfusion on outcomes among infected surgical patients. METHODS: Data on all hospital-acquired infectious episodes among surgical intensive care unit and ward patients were collected prospectively over 39 months at a single university hospital. The relationships between prior transfusion (defined as the receipt of allogeneic red blood cells or platelets during the index hospitalization but prior to the development of infection) and over 100 variables were examined using univariate and multiple logistic regression analysis, with inclusion of a propensity score for prior transfusion to attempt to account for treatment selection bias. RESULTS: During the study period, 1,228 infectious episodes occurred; 641 were associated with the transfusion of packed red blood cells or platelets. Univariate analysis revealed that patients with those infectious episodes following transfusion had higher Acute Physiology and Chronic Health Evaluation II (APACHE II) scores (18.3 +/- 0.3 vs. 10.9 +/- 0.3, p < 0.0001) and higher mortality (26.0% vs. 8.9%, p < 0.0001). Those patients who died received a greater number of transfusions prior to infection than those who lived (7.7 +/- 0.8 vs. 4.5 +/- 0.3, p = 0.0002). Multiple logistic regression analysis revealed that the propensity score for prior transfusion independently predicted mortality (odds ratio 9.45, 95% confidence interval 3.71-24.09, p < 0.001), but that neither the presence or absence of transfusion (OR 0.89, 95% CI 0.54-1.46, p = 0.6) nor the absolute number of units of red blood cells or platelets transfused (OR for red blood cells 1.00, 95% CI 0.98-1.02, p = 0.7; OR for platelets 0.97, 95% CI 0.90-1.05, p = 0.5) independently predicted mortality. CONCLUSIONS: The transfusion of packed red blood cells or platelets prior to infection is associated with more severe disease among surgical patients, but once corrected for treatment selection bias does not appear to worsen outcomes from infection.

Anti-Bacterial Agents↗

PubMed2006

Antibiotic therapy and 48-hour mortality for patients with pneumonia.

PURPOSE: Although numerous articles have demonstrated that recommended empiric antimicrobial regimens are associated with decreased mortality at 30 days, there is controversy over whether appropriate antibiotic selection has a beneficial impact on mortality within the first 48 to 96 hours after admission. Our aim was to determine whether the use of guideline-concordant antibiotic therapy is associated with decreased mortality within the first 48 hours after admission for patients with pneumonia. METHODS: A retrospective cohort study was conducted at two tertiary teaching hospitals in San Antonio, Texas. A propensity score was used to balance the covariates associated with the use of guideline-concordant antimicrobial therapy. A multivariable logistic regression model was used to assess the association between mortality within 48 hours and the use of guideline-concordant antibiotic therapy, after adjusting for potential confounders including the propensity score. RESULTS: Information was obtained on 787 patients with community-acquired pneumonia. The median age was 60 years, 79% were male, and 20% were initially admitted to the intensive care unit. At presentation 52% of subjects were low risk, 34% were moderate risk, and 14% were high risk. Within the first 48 hours, 20 patients died. After adjustment for potential confounders, the use of guideline-concordant antimicrobial therapy (odds ratio 0.37, 95% confidence interval, 0.14-0.95) was significantly associated with decreased mortality at 48 hours after admission. CONCLUSION: Using initial empiric guideline-concordant antimicrobial therapy is associated with decreased mortality at 48 hours. Further research needs to investigate methods to ensure that patients with community-acquired pneumonia are treated with appropriate antimicrobial therapies.

Adult↗

PubMed2004

Composite arterial grafts versus conventional grafting for coronary artery bypass grafting.

OBJECTIVES: Composite arterial grafts for coronary artery bypass grafting surgery allow complete arterial revascularization but are limited by the inflow of a single internal thoracic artery supplying all the grafted vessels. We reviewed the safety of composite arterial grafts using either bilateral internal thoracic arteries or a single internal thoracic artery and radial artery. METHODS: From January 1999 to July 2002, 402 consecutive patients receiving composite grafts only were compared to a control group of patients (n = 542) undergoing coronary artery bypass grafting with internal thoracic artery and saphenous veins operated upon by the same surgeons. Two different statistical approaches were used to compare groups in this retrospective analysis. First, propensity score analysis with greedy matching technique was used to match patients from each group. Second, a multivariate analysis was performed looking at a combined patient outcome of death, intra-aortic balloon counterpulsation utilization, myocardial infarction, stroke, and prolonged ventilation on all patients in both groups. RESULTS: After matching by propensity score, the major clinical outcomes in composite arterial (n = 249) and control (n = 249) groups were found to be similar. The in-hospital mortality in the composite group was 1.2% as compared with 0.4% in matched patients (P =.62). However, patients in the composite group were found to have a significantly longer pump time (P <.0001), longer clamp time (P <.0001), increased incidence of prolonged mechanical ventilation (12.8% vs 4.8%; P =.002), and higher incidence of combined morbidity outcome (13.6% vs 6.4%; P =.007) as compared with matched patients. Multivariable analysis showed that composite arterial grafting was an independent predictor of the combined morbidity outcome with an odds ratio of 2.1 (1.2-3.7). CONCLUSIONS: These findings suggest that composite arterial grafting may be associated with an increase in risk-adjusted patient morbidity when compared with a conventional coronary artery bypass grafting group, although a mortality difference was not demonstrable.

Adult↗

PubMed2006

Prospective multicentre evaluation of adverse outcomes following treatment for complicated diverticular disease.

BACKGROUND: The choice of operation for complicated diverticular disease is contentious. The aim of this study was to investigate adverse events following restorative (primary resection and anastomosis, PRA) and non-restorative (Hartmann's procedure, HP) surgery for complicated diverticular disease. METHODS: Five hundred and thirty-nine patients who presented with complicated diverticular disease in 42 centres over a 12-month period from January 2003 were considered for the study. Data were collected prospectively from 248 patients (46.0 per cent) who underwent PRA and 167 (31.0 per cent) who had HP. A propensity score was developed for case-mix adjustment. Multifactorial logistic regression was used to evaluate differences in operative outcomes. RESULTS: Mortality, surgical and medical complication rates were 4.0, 31.0 and 13.7 per cent respectively after PRA, and 23.4, 53.3 and 40.7 per cent for HP (all P < 0.001). After adjusting for the propensity score, the HP group had a 2.1- and 1.9-fold increase in medical and surgical complications respectively compared with those who had PRA, whereas the operative mortality rate was not significantly different. Non-colorectal surgeons performed a significantly higher proportion of HPs in the non-elective setting than colorectal surgeons (80.6 versus 60.4 per cent; chi(2) = 8.31, 1 d.f., P = 0.004). CONCLUSION: PRA with or without a proximal diversion is more often performed non-electively by specialist colorectal surgeons. It may be a safe procedure for complicated diverticular disease in selected patients as it may be associated with fewer postoperative adverse events.

Adult↗

PubMed2002

Stroke after conventional versus minimally invasive coronary artery bypass.

BACKGROUND: Postoperative stroke is a serious complication after coronary artery bypass grafting with cardiopulmonary bypass (on-pump), and portends higher morbidity and mortality. It is unknown whether an off-pump cardiopulmonary bypass (OPCAB) approach may yield a lower stroke rate over conventional on-pump coronary artery bypass grafting. METHODS: From June 1994 to December 2000, OPCAB was performed in 2,320 patients and compared with 8,069 patients who had on-pump coronary artery bypass grafting, during the same period of time. The patients undergoing OPCAB were randomly matched to on-pump patients by propensity score. A logistic regression model was used to test the difference in the postoperative stroke rate between OPCAB and on-pump procedures controlling for the correlation between matched sets. A multiple logistic regression model predicting the risk of stroke adjusted by stroke risk factors and operation type was also computed. RESULTS: Matches by propensity score were found for 72% of the patients undergoing OPCAB. Patients undergoing on-pump coronary artery bypass grafting were 1.8 (95% confidence interval 1.0 to 3.1, p = 0.03) times more likely to suffer a stroke postoperatively than OPCAB patients after controlling for preoperative risk factors through matching. Independent predictors of stroke identified from the multiple logistic model included on-pump operation (versus OPCAB operation), female gender, 4 to 6 vessels grafted (versus <4 grafts), hypertension, history of previous cerebrovascular accident, carotid artery disease, chronic obstructive pulmonary disease, and depressed ejection fraction. CONCLUSIONS: Off-pump cardiopulmonary bypass avoids the risks of cardiopulmonary bypass and atrial trauma. A substantially lower stroke rate suggests that OPCAB is a neurologically safe treatment option for revascularization.

Aged↗

PubMed2005

Inhaled corticosteroids in chronic obstructive pulmonary disease: results from two observational designs free of immortal time bias.

RATIONALE: Recent cohort studies in chronic obstructive pulmonary disease (COPD) have questioned the validity of previously reported associations between inhaled corticosteroids (ICS) and reductions in mortality and rehospitalization in observational studies. Using time-dependent versions of statistical survival models, these studies have suggested immortal time bias as responsible for the proposed beneficial association. OBJECTIVES: We explored the extent of this bias in a study of patients with COPD monitored for a year from COPD discharge with two designs free of any immortal time bias in the General Practice Research Database in the United Kingdom. METHODS: In Design 1, we used only patients whose treatment status was defined on the same day of discharge to obtain a matched cohort based on propensity scores, which were derived from the patient-level baseline characteristics. In Design 2, we identified all in the study cohort who experienced death or rehospitalization and then matched each case to up to four noncases by randomly sampling from the cohort risk sets without regard to treatment status. MEASUREMENTS AND MAIN RESULTS: The propensity scores matched cohort analysis of 786 patients without a wait time found a significant risk reduction associated with use of ICS: hazard ratio, 0.69 (95% confidence interval, 0.52-0.93). The matched nested case-control analysis of 2,222 patients, designed without regard to exposure status and hence free of immortal time bias, gave a similar association with exposure to ICS in the last 6-month period: hazard ratio, 0.71 (0.56-0.90). CONCLUSIONS: We conclude that immortal time bias cannot account for the risk reduction associated with ICS exposure in observational studies.

Administration, Inhalation↗

PubMed2000

Ordering an echocardiogram for evaluation of left ventricular function: level of expertise necessary for efficient use.

This prospective study was performed to test the hypothesis that the yield of 2-dimensional echocardiography (2DE) would be higher when it is ordered by a cardiologist than by a noncardiologist. Patients referred for transthoracic 2DE for the evaluation of left ventricular systolic function for the 11-month period between July 10, 1995, and June 10, 1996, were included in the study. Demographic, historical, and clinical findings were recorded. Whether the patient was referred by a cardiologist versus a noncardiologist was used as the predictor variable in a binary logistic regression analysis. To address the possibility that the yield of 2DE may be higher for cardiologists because the prevalence of disease in patients referred to them may be higher (selection bias), the analysis was subjected to a propensity score adjustment. Of 2176 patients referred for 2DE during the study, 1033 were referred for the evaluation of left ventricular function. The test had a positive yield in 52% of patients for cardiologists versus 31% for noncardiologists (chi(2) = 45.5, P <.0001, odds ratio 2.4 [CI = 1. 9-3.1]). This difference remained highly significant even when propensity score risk adjustment was made (chi(2) = 54.2, P <.0001, odds ratio 2.0 [CI = 1.5-2.8]). We conclude that the yield of 2DE is higher for cardiologists compared with noncardiologists and that this result was not related to differences in patient populations examined by the two groups. Thus, more efficient use of 2DE may be achieved if patients are referred to cardiologists rather than directly sent for 2DE.

Aged↗

PubMed2002

Association of educational status with heart rate recovery: a population-based propensity analysis.

PURPOSE: An abnormally attenuated heart rate recovery after exercise is a predictor of mortality that is thought to reflect decreased parasympathetic activity. Lower educational level may be associated with automatic imbalance. We sought to assess the association of educational level with heart rate recovery. SUBJECTS AND METHODS: Among 5246 healthy adults from a population-based cohort who underwent exercise testing, 874 (17%) did not graduate from high school, 1823 (35%) completed high school, and 2549 (49%) attended at least some college. An abnormal heart rate recovery was defined as a difference of </=42 beats per minute between the peak heart rate and that after 2 minutes of recovery. Propensity scores were used to account for differences by educational status. RESULTS: An abnormal heart rate recovery was more common among adults who did not graduate from high school compared with those who attended at least some college (50% [440/874] vs. 28% [701/2549]; odds ratio [OR]: 2.7; 95% confidence interval [CI]: 2.3 to 3.1; P <0.001). After using propensity scores, lower educational status remained associated with an abnormal heart rate recovery (OR = 1.9; 95% CI: 1.6 to 2.4; P <0.001). During 12-years of follow-up, there were 327 deaths. Poor educational status was associated with greater mortality (9% [80/874] vs. 6% [247/4372]; unadjusted hazard ratio [HR] = 1.9; 95% CI: 1.4 to 2.5; P <0.001). However, after accounting for age, sex, and heart rate recovery, educational status was a weaker predictor (HR = 1.3; 95% CI: 1.0 to 1.7). CONCLUSIONS: Educational status is independently associated with an abnormal heart rate recovery.

Adult↗

PubMed2006

Platelet transfusions are not associated with increased morbidity or mortality in cardiac surgery.

PURPOSE: To determine the independent relationship between leukoreduced platelet transfusions and adverse events in cardiac surgery. METHODS: In this observational study, detailed baseline and perioperative data were prospectively collected on consecutive patients who underwent cardiac surgery at a single institution from 1999 to 2004. The independent associations of platelet transfusion with clinical outcomes (low output syndrome, myocardial infarction, stroke, renal failure, sepsis, and death) were determined by multivariable logistic regression analysis and propensity score case-control analysis. RESULTS: Of the 11,459 patients analyzed, 2,174 (19%) received (leukoreduced) platelets - 1,408 received 5 U, 471 received 10 U, 140 received 15 U, and 155 received 20 or more units. Although all measured adverse event rates were higher in those who received platelets, in neither the logistic regression analyses nor the propensity score analyses was there any association between platelet transfusion and any of the adverse events. CONCLUSIONS: Transfusion of leukoreduced platelets in cardiac surgery is not associated with adverse clinical outcomes when adjustments are made for important confounders.

Cardiac Surgical Procedures↗

PubMed2002

Is there a benefit to early angiography in patients with ST-segment depression myocardial infarction? An observational study.

BACKGROUND AND OBJECTIVE: Patients with ST-segment depression myocardial infarction (MI) have a similar long-term outcome compared with those who have ST-segment elevation. It remains unclear whether an aggressive treatment approach with very early (<6 hours) angiography and revascularization improves outcome over an early conservative approach. We compared the short-term outcome of patients who received very early (<6 hours) angiography with patients who received early conservative therapy for ST-segment depression MI. METHODS: Patients seen within 12 hours with ST-segment depression on the initial electrocardiogram (ECG) were identified from the National Registry of Myocardial Infarction 2 (NRMI) database, which collected information from 1994 to 1998. Those who received very early (<6 hours) angiography were compared with those who received early conservative therapy. The short-term outcomes, including major bleeding episodes, cerebral vascular events, recurrent ischemia and angina, MI, and death, were compared on the basis of the initial therapy received. RESULTS: Patients treated with very early angiography (2402) were younger, more likely to be males, smokers, and have less of a cardiac history (angina, MI, congestive heart failure, aortocoronary bypass surgery) and less likely to have diabetes mellitus than those who received early conservative therapy (17,735). Hospital outcome in the very early angiography group was similar to the early conservative therapy group in terms of cerebral vascular events (0.8% vs 1.0%, P =.27), major bleeding events (2.8% vs 2.4%, P =.25), and recurrent MI (2.1% vs 2.3%, P =.57) but was associated with lower recurrent ischemia or angina (11.4% vs 16.7%, P <.001) and improved survival (death, 4.9% vs 7.3%, P <.001). Multivariate analysis suggested that patients receiving very early angiography had lower mortality compared with those receiving early conservative therapy (odds ratio [OR] = 0.76; 95% CI 0.60-0.95). However, comparing patients matched on propensity score (1405) showed mortality was similar in both treatment groups (5.6% vs 5.4%, P =.87), with no significant inhospital mortality benefit of very early angiography (OR = 0.89; 95% CI 0.71-1.13). CONCLUSIONS: The apparent mortality benefit of very early angiography in patients with ST-segment depression MI is a reflection of bias by confounding. Controlling for baseline differences using propensity score methods in this observational study indicated no inhospital mortality benefit of a very early aggressive approach compared with a conservative approach.

Age Factors↗

PubMed2002

Increase in lifetime adverse drug reactions, service utilization, and disease severity among patients who will start COX-2 specific inhibitors: quantitative assessment of channeling bias and confounding by indication in 6689 patients with rheumatoid arthritis and osteoarthritis.

OBJECTIVE: Nonrandom assignment of therapy in observational studies and clinical practice can be accompanied by channeling bias and confounding by indication. This in turn can lead to unreliable conclusions about treatment effectiveness. Although widely acknowledged as important, no studies in rheumatology have measured the extent of these biases. We identified variables contributing to confounding and investigated the strength of the confounding effect. Analytical methods (propensity scores) are available to mitigate the effect of nonrandom assignment if the full extent of confounding can be understood. METHODS: A population of 6637 patients with rheumatoid arthritis (RA) and osteoarthritis (OA) from the practices of 433 US rheumatologists completed 2 sets of detailed questionnaires concerning (1) the last 6 months in 1998 and (2) the first 6 months of 1999, generally prior to and after the release of celecoxib and rofecoxib. Patients who received the COX-2 specific inhibitors in period 2 were identified (n = 1517), and their characteristics were compared to the 5120 who did not start a new COX-2 specific inhibitor during Period 1. RESULTS: Patients starting a new COX-2 specific inhibitor had a greater lifetime history of adverse reactions of all kinds, but particularly gastrointestinal adverse drug reactions. They also had more severe scores for pain, functional disability, fatigue, helplessness, and global severity, and they used more inpatient and outpatients services than patients who would not switch to COX-2 specific inhibitors. CONCLUSION: Confounding by indication and channeling bias result in an overall increase in severity of about 25% for the above measures. Observational studies should account for these biases by a broadly defined propensity score that includes the variables identified in this report. These observations are germane to observational studies of disease modifying antirheumatic drugs and biologics, as well, and suggest the need for careful control of confounders when assessing treatment effects in rheumatic disease observational studies.

Aged↗

PubMed2004

The rise and decline of nonsteroidal antiinflammatory drug-associated gastropathy in rheumatoid arthritis.

OBJECTIVE: Nonsteroidal antiinflammatory drug (NSAID)-associated gastropathy is a major cause of hospitalization and death. This study was undertaken to examine whether recent preventive approaches have been associated with a declining incidence of NSAID gastropathy, and, if so, what measures may have caused the decline. METHODS: We studied 5,598 patients with rheumatoid arthritis (RA) over 31,262 patient-years at 8 sites. We obtained standardized longitudinal information on the patients that had been previously used to establish the incidence of NSAID gastropathy, and also information on patient risk factors and differences in toxicity between NSAIDs. Consecutive patients were followed up with biannual Health Assessment Questionnaires and medical record audits between 1981 and 2000. The major outcome measure was the annual rate of hospitalization involving bleeding, obstruction, or perforation of the gastrointestinal (GI) tract and related conditions. RESULTS: Rates of GI-related hospitalizations rose from 0.6% in 1981 to 1.5% in 1992 (P < 0.001), and then declined to 0.5% in 2000 (P < 0.001). The fitted spline curve fit the data well (R2 = 0.70). The period of rise was mainly associated with increasing patient age and the GI risk propensity score. The period of decline was associated with lower doses of ibuprofen and aspirin, a decline in the use of "more toxic" NSAIDs from 52% to 42% of patients, a rise in the use of "safer" NSAIDs from 19% to 48% of patients, and increasing use of proton-pump inhibitors, but not with change in age, NSAID exposure, or GI risk propensity score. CONCLUSION: The risk of serious NSAID gastropathy has declined by 67% in these cohorts since 1992. We estimate that 24% of this decline was the result of lower doses of NSAIDs, while 18% was associated with the use of proton-pump inhibitors and 14% with the use of less toxic NSAIDs. These declines in the incidence of NSAID gastropathy are likely to continue.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2005

Association of intravenous morphine use and outcomes in acute coronary syndromes: results from the CRUSADE Quality Improvement Initiative.

BACKGROUND: Although intravenous morphine is commonly used for the treatment of chest pain in patients presenting with non-ST-segment elevation acute coronary syndromes (NSTE ACS), its safety has not been evaluated. The CRUSADE Initiative is a nonrandomized, retrospective, observational registry enrolling patients with NSTE ACS to evaluate acute medications and interventions, inhospital outcomes, and discharge treatments. METHODS: The study population comprised patients presenting with NSTE ACS at 443 hospitals across the United States from January 2001 through June 2003 (n = 57,039). Outcomes were evaluated in patients receiving morphine versus not and between patients treated with morphine versus intravenous nitroglycerin. RESULTS: A total of 17,003 patients (29.8%) received morphine within 24 hours of presentation. Patients treated with any morphine had a higher adjusted risk of death (odds ratio [OR] 1.48, 95% CI 1.33-1.64) than patients not treated with morphine. Relative to those receiving nitroglycerin, patients treated with morphine also had a higher adjusted likelihood of death (OR 1.50, 95% CI 1.26-1.78). Utilizing a propensity score matching method, the use of morphine was associated with increased inhospital mortality (OR 1.41, 95% CI 1.26-1.57). The increased risk of death in patients receiving morphine persisted across all measured subgroups. CONCLUSIONS: Use of morphine either alone or in combination with nitroglycerin for patients presenting with NSTE ACS was associated with higher mortality even after risk adjustment and matching on propensity score for treatment. This analysis raises concerns regarding the safety of using morphine in patients with NSTE ACS and emphasizes the need for a randomized trial.

Acute Disease↗

PubMed2006

The Italian Multiple Sclerosis Database Network (MSDN): the risk of worsening according to IFNbeta exposure in multiple sclerosis.

We evaluated the risk of worsening according to the length of exposure to interferon beta (IFNbeta) in a large cohort of 2090 multiple sclerosis patients collected by the Italian MS Database Network. Overall 44,140 patient-visits with a follow-up of 22,143 patient-years were evaluated. Forty-one per cent of patients were exposed to IFNbeta for up to 2 years, 39% for 2-4 years and 20% for more than 4 years. A Cox regression model was used to analyse two clinical outcomes: disability progression and worsening of relapse rate. The technique of propensity score was applied to reduce bias in the comparison of non-randomized groups. The risks of disability progression (HR =0.23; 95% CI: 0.17-0.30) and worsening of relapse rate (HR =0.19; 95% CI: 0.14-0.27) were reduced by about 4-5-fold in patients exposed to IFNbeta for more than four years, compared with patients exposed for up to two years. The propensity score technique confirmed the findings. The proportion of days covered by IFNbeta treatment was lower (P <0.0001) in patients exposed to IFNbeta for up to two years than in other groups. A clinical stabilization over two years of IFNbeta exposure may predict a subsequent good clinical response to treatment.

Adjuvants, Immunologic↗

PubMed2005

The effect of prompt physician visits on intensive care unit mortality and cost.

OBJECTIVE: To determine the effect on mortality, length of stay, and direct variable cost of physician response time to seeing patients after intensive care unit admission. DESIGN: Retrospective analysis of the intensive care unit database. SETTING: Medical center. PATIENTS: Subjects were 840 patients who had complete direct variable cost data and a subset of 316 patients who were matched by propensity scores. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Median time to first visit by a physician was 6 hrs. One hundred thirty-five patients (16.1%) died in hospital compared with 25.0% predicted by Acute Physiology and Chronic Health Evaluation risk (p < .001). Higher Acute Physiology and Chronic Health Evaluation risk, older age, mechanical ventilation on arrival in the intensive care unit, and longer time until seen by a physician were predictors of hospital mortality. Each 1-hr delay in seeing the patient was associated with a 1.6% increased risk of hospital death, which further increased to 2.1% after including propensity score. However, patients seen more promptly (<6 vs. >6 hrs) had greater hospital direct variable cost ($11,992 +/- $12,043 vs. $10,355 +/- $10,368, p = .04), before controlling for acuity of illness and other factors that may have affected time to evaluation. In the subpopulation of propensity-matched patients, patients seen promptly (<6 vs. >6 hrs) had shorter hospital length of stays (11 +/- 11 vs. 13 +/- 14 days, p = .03) but similar direct variable costs ($10,963 +/- 10,778 vs. $13,016 +/- 13,006, p = .16) and similar mortality rates (24 vs. 30, p = .46). CONCLUSIONS: In the total patient population, delay in seeing patients was associated with an increased risk of death. In the propensity-matched patients, promptly seen patients had shorter hospital stays but similar direct variable costs.

APACHE↗

PubMed2004

Aspirin dose and six-month outcome after an acute coronary syndrome.

OBJECTIVES: This study was designed to compare the efficacy of low and intermediate aspirin doses in acute coronary syndromes. BACKGROUND: Little is known of the comparative efficacy of low and intermediate aspirin doses in this setting. METHODS: We compared six-month death, myocardial infarction (MI), and stroke in patients with unstable angina or acute MI discharged while receiving low (<150 mg) or intermediate (> or =150 mg) aspirin therapy in the GUSTO IIb and PURSUIT trials (n = 20,521). We used multivariable analysis and performed a propensity analysis in order to adjust for baseline imbalances between the groups. RESULTS: Aspirin doses <150 mg were prescribed to 29.9% (6,128) of patients. By six months, 6.4% of the patients (1,310 of 20,521) had a primary event, 6.2% of the patients receiving <150 mg and 6.6% of the patients receiving aspirin doses > or =150 mg (hazard ratio [HR] 1.06 [95% confidence interval (CI) 0.94 to 1.19], p = 0.35). After adjusting for baseline imbalances and the propensity score for discharge aspirin dose, there was no effect of aspirin dose on the composite end point at six months (HR 0.92 [95% CI 0.79 to 1.07], p = 0.28). However, the higher aspirin dose was associated with a reduction in six-month MI (HR 0.79 [95% CI 0.64 to 0.98], p = 0.03). The outcome was similar when patients were matched on the basis of the propensity score for aspirin dose (HR for death/MI/stroke 0.94 [95% CI 0.80 to 1.12], p = 0.51), although stroke occurred significantly more frequently among patients receiving the higher aspirin dose (HR 1.74 [95% CI 1.01 to 3.02] p = 0.05) and the effect on MI was no longer apparent. CONCLUSIONS: Although these data are non-randomized, they suggest that the aspirin dose upon discharge may influence the clinical course after unstable angina or acute MI.

Aged↗

PubMed2003

Frequency of thrombolytic therapy in patients with acute ischemic stroke and the risk of in-hospital mortality: the German Stroke Registers Study Group.

BACKGROUND AND PURPOSE: There is little information about early outcome after intravenous application of tissue-type plasminogen activator (tPA) for stroke patients treated in community-based settings. We investigated the association between tPA therapy and in-hospital mortality in a pooled analysis of German stroke registers. METHODS: Ischemic stroke patients admitted to hospitals cooperating within the German Stroke Registers Study Group (ADSR) between January 1, 2000, and December 31, 2000, were analyzed. The ADSR is a network of regional stroke registers, combining data from 104 academic and community hospitals throughout Germany. Patients treated with tPA were matched to patients not receiving tPA on the basis of propensity scores and were analyzed with conditional logistic regression. Analyses were stratified for hospital experience with the administration of tPA. RESULTS: A total of 13,440 ischemic stroke patients were included. Of these, 384 patients (3%) were treated with tPA. In-hospital mortality was significantly higher for patients treated with tPA compared with patients not receiving tPA (11.7% versus 4.5%, respectively; P<0.0001). After matching for propensity score, overall risk of inpatient death was still increased for patients treated with tPA (odds ratio [OR], 1.7; 95% CI, 1.0 to 2.8). Patients receiving tPA in hospitals that administered 5 thrombolytic treatments per year (OR, 1.3; 95% CI, 0.8 to 2.4). CONCLUSIONS: In-hospital mortality of ischemic stroke patients after tPA use varied between hospitals with different experience in tPA treatment in routine clinical practice. Our study suggested that thrombolytic therapy in hospitals with limited experience in its application increase the risk of in-hospital mortality.

Adult↗