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Results for “Propensity Score”

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At least 433 records · Page 24Linked to original sources

PubMed2004

Late results of first myocardial revascularization in multiple vessel disease: single versus bilateral internal mammary artery with or without saphenous vein grafts.

OBJECTIVE(S): We evaluated our experience to investigate if the use of bilateral internal mammary artery (BIMA) grafting, with or without complementary saphenous vein grafts (SVGs), if compared to the use of single IMA and SVG(s), increases the quality of the results of coronary bypass grafting in patients younger than 75 years who undergo first myocardial revascularization. METHODS: From September 1986 to December 1999, 1602 patients younger than 75 years underwent first myocardial revascularization using left internal mammary (LIMA) to left anterior descending (LAD) and SVG(s) (n=576) or BIMA (one IMA on the LAD) with or without SVG(s) (n=1026). Propensity score analysis was used to select 1140 patients with the same preoperative and operative characteristics. Thirty day outcome was evaluated as well as 10-year freedom from death by any cause, cardiac death, acute myocardial infarction (AMI), AMI in a grafted area (GA), redo/PTCA, redo/PTCA in a GA, target cardiac events (death from cardiac cause, AMI in a GA, redo/PTCA in a GA), and any event. Follow-up ranged from 3.5 to 16.8 years (mean 7.3+/-4.8 years). RESULTS: Thirty day mortality was 2.8% in Group LIMA and 2.1% in Group BIMA, P n.s.; incidence of major complications was, respectively, 7.0 versus 5.4%, P n.s. Group BIMA showed better 10-year freedom from cardiac death (96.5+/-0.8 versus 91.3+/-1.4, P=0.0288), AMI (98.0+/-0.6 versus 94.3+/-1.2, P=0.0180), AMI in a GA (98.4+/-0.6 versus 94.7+/-1.1, P=0.0057) and target cardiac events (93.9+/-1.1 versus 86.3+/-1.8, P=0.0388). Cox analysis confirmed that LIMA+SV(s) was an independent risk factor from lower freedom from cardiac death, AMI, AMI in a GA and cardiac events. CONCLUSIONS: As freedom from cardiac events is a main target of any revascularization procedure, we think that, when a patient undergoes a first coronary surgery and is younger than 75 years, BIMA grafting should not be denied, especially if his life expectancy is higher than 10 years.

Aged↗

PubMed2004

Does off-pump coronary artery bypass reduce the incidence of post-operative atrial fibrillation? A question revisited.

Atrial fibrillation (AF) is the most common post-operative complication in patients undergoing coronary artery bypass grafting, with an increased incidence associated with advancing age. This study aims to determine whether off-pump coronary artery bypass (OPCAB) reduces the incidence of AF in a generalized population (mean age <70 years). A meta-analysis was performed including all randomised and propensity score matched non-randomised studies published between 2001 and 2003 reporting a comparison between the two techniques in a generalised patient group (average age <70 years). The primary outcome of interest was post-operative AF. Sensitivity analysis was performed to evaluate consistency of the calculated treatment effect. Fourteen studies fulfilled our inclusion criteria, including a total of 16,505 subjects. The incidence of AF was 19% (1612/8265) in the off-pump group versus 24% (1976/8240) in the on-pump group. When considering only the 11 randomised studies (2207 subjects), we found a significant reduction in the incidence of post-operative AF in the off-pump group using a random-effect model (odds ratio (OR)=0.60, 95% confidence interval (CI)=0.45-0.82, and chi-square of heterogeneity=18.02, P=0.05). Sensitivity analysis highlighted one randomised study causing funnel plot asymmetry, exclusion of which resulted in a significant reduction in the incidence of post-operative AF in the off-pump group (OR=0.71, 95% CI=0.57-0.90), with a non-significant heterogeneity of 3.91 (P=0.92). When only studies of high quality were considered (898 patients), no significant difference was seen between on and off-pump groups (OR=0.78, 95% CI=0.57-1.07, and heterogeneity=0.53, P=0.91). This may be due to small number of patients in this group. Our results suggest that although OPCAB surgery may reduce the incidence of post-operative AF in a generalised population (age <70 years) this finding is not clearly supported by high quality randomised trials. Although previous evidence suggests that the incidence of post-operative AF is reduced in an elderly population (>70 years) with off-pump surgery, our results show that the evidence is less clear in a younger population group. The question of whether off-pump surgery in this patient group results in a lower rate of post-operative AF remains to be answered by further high quality randomised research.

Adult↗

PubMed2005

Influence of diabetes and bilateral internal thoracic artery grafts on long-term outcome for multivessel coronary artery bypass grafting.

OBJECTIVE: Diabetes mellitus is a major independent risk factor for morbidity and mortality after coronary artery bypass grafting (CABG). The aim of this study was to assess the effect of bilateral (B) internal thoracic artery grafting (ITA) in diabetic patients with multivessel CABG. METHODS: Between 1985 and 1995, 4382 patients underwent primary isolated multivessel CABG with ITA grafting and concomitant saphenous vein grafting (SVG). Outcome of diabetic and nondiabetic patients undergoing single (S) ITA+SVG (n=419 and 2079) and BITA+SVG (n=214 and 1594) grafting was obtained at a mean follow-up of 11+/-3 years. RESULTS: Diabetic patients were older, included more women, and had more obesity, hypertension and peripheral vascular disease than nondiabetic patients. Deep sternal wound infection rate was 1.9% for diabetic patients vs 1.2% for nondiabetic patients (P=0.2) and 30-day mortality was 1.7 vs 1.8% (P=0.9). Cox regression analysis with interaction term and propensity scoring showed that BITA grafting decreased the risk of death (Hazard Ratio=0.72 [0.57-0.91, 95%CI]) and coronary reoperation (HR=0.38 [0.19-0.77]) in both diabetic and nondiabetic patients, with no significant interaction noted. BITA grafting decreased the risk of myocardial infarction at long-term follow-up in nondiabetic patients (HR=0.72 [0.60-0.86]) but not in diabetic patients. Ten-year freedom rate from myocardial infarction in diabetic patients was 80 and 76% for SITA and BITA grafting patients, respectively. However, survival following myocardial infarction was better for patients who underwent BITA grafting, in both diabetic and nondiabetic subgroups. CONCLUSIONS: BITA+SVG grafting in diabetic patients improves survival and decrease coronary reoperation compared with SITA+SVG at long-term follow-up. Survival following myocardial infarction is improved with BITA grafting.

Age Factors↗

PubMed2004

Risk factors for hemorrhage-related reexploration and blood transfusion after conventional versus coronary revascularization without cardiopulmonary bypass.

OBJECTIVE: The premise of coronary revascularization without cardiopulmonary bypass (off-pump CABG) proposes that patient morbidity and, potentially, mortality can be reduced without compromising the excellent results of conventional revascularization techniques (on-pump CABG). It is unknown, however, whether coronary artery bypass without cardiopulmonary bypass (off-pump CABG) is associated with similar hemorrhage related reexploration rates and blood transfusion requirements compared to the on-pump approach. METHODS: Between January 1998 and June 2002, 3646 patients underwent off-pump CABG and were compared with a contemporaneous control group of 5197 on-pump CABG patients. A logistic regression model was used to test the difference in the postoperative hemorrhage related reexploration rates and need for postoperative blood transfusions between the groups, controlling for preoperative risk factors. The patients undergoing off-pump CABG were matched to on-pump patients by propensity score. RESULTS: Hemorrhage related reexploration rates were comparable between the 2 groups (odds-ratio [OR]=0.80, 95% confidence intervals [CI]=0.55-1.09, P=0.15). Off-pump CABG was associated with a lower need for single and multiple unit postoperative blood transfusions (OR=0.30, CI=0.24-0.31, P<0.01 and OR=0.4, CI=0.36-0.51, P<0.01, respectively) compared to on-pump CABG patients. CONCLUSIONS: Off-pump CABG eliminates the risks of cardiopulmonary bypass and the systemic inflammatory response it elicits. A substantially lower need for postoperative blood transfusions and a comparable hemorrhage-related reexploration rate suggests that off-pump CABG may avoid the morbidity and mortality associated with excessive postoperative blood loss.

Adult↗

PubMed2005

The effect of chronic steroid therapy on outcomes following cardiac surgery: a propensity-matched analysis.

OBJECTIVE: Steroids are beneficial in reducing the inflammatory response accompanying surgery with cardiopulmonary bypass. However, chronic steroid therapy has been implicated as a risk factor for abdominal complications and mortality following surgery. We assessed the impact of chronic steroid therapy had on outcome following cardiac surgery. METHODS: During the period January 1999 to March 2003 there were 98 patients on chronic steroid therapy (Group S) who underwent cardiac surgery at our institution. These patients were matched with a control group of 98 patients who were not on steroids (Group C). A propensity score was used to perform the matching. The C statistic for this model was 0.72. RESULTS: Ninety (93.7%) of the 98 patients in Group S had been on oral prednisolone for a median of 9.5 years (25th and 75th percentile of 5 and 12 years) with a median dose of 5mg (25th and 75th percentile of 4 and 8.75 mg). Preoperative characteristics were well matched between both groups. There was no difference in the post-operative outcome between the two groups with respect to mortality, stroke, renal failure, abdominal complications, wound infections, requirement for inotropic support and myocardial infarction. Patients in Group S were more likely to develop atrial arrhythmias and to require prolonged ventilation, although this did not reach statistical significance. CONCLUSIONS: Chronic steroid therapy was not associated with increased mortality or overall morbidity following cardiac surgery. However, patients on chronic steroids may be at greater risk of developing atrial arrhythmias or of requiring prolonged ventilation.

Aged↗

PubMed2006

Does off-pump surgery offer benefit in high respiratory risk patients? A respiratory risk stratified analysis in a propensity-matched cohort.

OBJECTIVE: The role of off-pump surgery in high respiratory risk patients remains unclear. In this study, we aim to evaluate the effect of off-pump surgery on high respiratory risk patients. METHODS: To achieve comparative groups, a five digit propensity score matching with 18 pre-operative variables was performed on 4406 consecutive CABG patients operated between January 2000 and September 2003. Respiratory risk stratification was performed with the following variables: (1) FEV(1)<65% of predicted, (2) patients>75 years old, (3) history of current smoking, (4) body mass index more than 40 kg/m(2) and (5) NYHA class IV dyspnoea in combination with current respiratory medication. The presence of two or more variables defined high risk. The primary end point was post-operative ventilation time. We also compared alveolar arterial gradients (A-a gradient) on admission to ITU, 2 and 4h using Friedman rank time analysis. RESULTS: We matched 1353 off-pump patients with 1353 unique on-pump patients. Respiratory risk stratified selection resulted in 73 off-pump and 55 on-pump high-risk patients. In the off-pump group, four (5.5%) patients had more than two selection criteria, compared to one (1.8%) for on-pump patients (p=0.29). The off-pump group had more patients with FEV1<65% compared to on-pump: 65 (89.0%) versus 40 (72.7%); p=0.017. The median ventilation time was significantly shorter for off-pump patients (7h [IQR: 5-14] vs 12h [IQR: 7-18], p=0.003). In the off-pump group, three (4.1%) patients had a ventilation time>48 h compared to eight (14.6%) in the on-pump group, p=0.037. A-a gradient measurements on admission to ITU were lower in off-pump patients (median: 182.3 [IQR: 126.6-216.2]) compared to on-pump patients (median: 194.7 [IQR 139.7-245.4], p=0.064). CONCLUSION: Off-pump surgery offers benefit to high respiratory risk patients by reducing post-operative ventilation time. Off-pump patients also have lower A-a gradients in the early post-operative period but this failed to reach significance.

Aged↗

PubMed2006

Prescription of beta-blockers in patients with advanced heart failure and preserved left ventricular ejection fraction. Clinical implications and survival.

BACKGROUND: The effects of beta-blockers in patients with heart failure (HF) and preserved left ventricular ejection fraction (LVEF) are not well established. AIMS: To assess the association between beta-blocker prescription at discharge and mortality in a cohort of patients with advanced HF and preserved LVEF. METHODS AND RESULTS: We prospectively studied a cohort of 443 patients with advanced HF and preserved LVEF (LVEF> or =40%). Mean age was 78 years, 56% female, 33% NYHA class IV. Overall, 227 patients (51%) had a beta-blocker prescribed at discharge. Mean duration of follow-up was 25 (+/-18) months. Death (all cause) occurred in 40 patients (17.6%) who were receiving a beta-blocker at discharge and 73 patients (33.8%) who were not on a beta-blocker. In multivariate Cox analysis, including adjustment for propensity score, prescription of a beta-blocker remained associated with a 43% relative mortality risk reduction (HR 0.57, 95% CI 0.37 to 0.88, p=0.01). CONCLUSIONS: In this cohort of patients with advanced HF and preserved LVEF, prescription of a beta-blocker was associated with a significant mortality reduction. This beneficial effect of beta-blocker use needs to be further confirmed in prospective, randomised clinical trials.

Adrenergic beta-Antagonists↗

PubMed2026

Clinical outcomes of fusion vs excision in the treatment of painful type II accessory naviculars: A matched cohort study.

BACKGROUND: For painful Type II accessory naviculars, whether to remove or fuse them remains unclear based on the current literature. This study aimed to investigate the clinical outcomes of fusion versus excision in treating painful type II accessory naviculars. METHODS: This retrospective comparative study included and followed 54 eligible patients (from May 2017 to March 2023). After 1:1 propensity score matching (PSM), 34 patients (17 fusion versus 17 excision) were analyzed. Outcomes included Visual Analog Scale (VAS), American Orthopaedic Foot and Ankle Society (AOFAS) midfoot score, Tegner score, complication rates, and radiographic measurements. Receiver operating characteristic (ROC) curve analysis was performed to identify the appropriate accessory navicular size cutoff for predicting nonunion following fusion. RESULTS: The mean follow-up was 35.0 ± 9.9 months. The fusion and excision groups showed significant and comparable VAS and AOFAS score improvements (p < .001). The fusion group had a higher complication rate (41.2% vs. 5.9%, p = .039), primarily nonunion and persistent pain. ROC curve analysis identified 50.3 mm² as the cutoff for nonunion risk; sizes < 50.3 mm² predicted high nonunion likelihood. CONCLUSIONS: Both fusion and excision are effective treatments for painful type II accessory naviculars, demonstrating acceptable pain and functional improvement during midterm follow-up. However, the lower complication rate along with relatively superior functional recovery favors the excision technique. For accessory naviculars smaller than 50.3 mm2, excision may be a better choice. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Humans↗

PubMed2005

Evaluating program effects on institutional delivery in Peru.

We evaluate the joint effects of two targeted Peruvian health programs on a mother's choice of whether to deliver in a public emergency obstetric care (EmOC) facility. The national maternal and child health insurance, or SMI Program, provided delivery care coverage to Peru's poorest households beginning in 1998. During 1996-2002, Proyecto 2000 sought to improve the quality of EmOC and increase utilization of public EmOC facilities in the districts reporting the highest maternal and neonatal mortality levels. Our data come from the Proyecto 2000 endline evaluation, which sampled 5335 mothers living in the catchment areas of 29 treatment and 29 matched control EmOC facilities. Using propensity scoring and two quality of care indices, we find significantly higher quality of care in Proyecto 2000 treatment facilities. Using variance components logistic models, we find a mother enrolled in the SMI Program was more likely to have delivered her last child in a public EmOC, controlling for household constraints. Residence in a Proyecto 2000 treatment area did not significantly affect the choice. A cross-level interaction term was insignificant, indicating the two program effects were independent.

Catchment Area, Health↗

PubMed2005

A comparison of population versus individual based cardiovascular disease prevention programs in Västerbotten, Sweden.

The purpose of this paper is to determine if differences in health outcomes of two cardiovascular disease prevention programs can be attributed to the inclusion of population based efforts in one of the programs. Propensity score matching has been used to eliminate possible selection bias. The results indicate that the intervention including population-based measures was not more effective than the intervention directed toward the individual.

Adult↗

PubMed2005

Does "the injury poverty trap" exist? A longitudinal study in Bavi, Vietnam.

In this study we concentrate on injuries and affected households' capacities to earn incomes. A longitudinal study was performed in Bavi district, Vietnam, with the specific objectives to investigate: (1) the affects of injuries on incomes by comparing income changes in injured and non-injured individuals; (2) the affect of injuries on social mobility by estimating households' relative risk of dropping into poverty for households with and without injuries and estimating the relative risk of escaping from poverty for households without and with injuries. The propensity score matching method using a logit model was used for data analysis. The results show that on average, the loss per household is estimated at VND 1,084,000 (USD 72) for poor and VND 2,598,000 (USD 173) for non-poor, equivalent to 11 (9) and 15 (13) working months of an average person in the poor and non-poor group, respectively, during 1999 (2001). The relative risk of dropping into poverty for non-poor households with and without injuries equal to 1.21 (p=0.08) and the relative risk of escaping from poverty between poor households without and with injuries equal to 0.96 (p=0.39). In conclusion, it has been argued that the introduction of user fees created a poverty trap and thus their removal may be a solution. However, user fees are only a part of the burden on households. Loss of income during the illness period is likely to be a problem of the same magnitude. A successful solution must thus follow two tracks: prepayment of health care and some insurance based compensation of income losses during the illness period. Both reforms, if they are persistent, must be done within the resource limits of the local society. If the risk of catastrophic illness is more evenly spread across the society, it would increase the general welfare even if no more resources are provided.

Data Collection↗

PubMed2005

Efficacy of lamivudine for preventing hepatocellular carcinoma in chronic hepatitis B: A multicenter retrospective study of 2795 patients.

A retrospective survey of Japanese patients histologically diagnosed with chronic hepatitis B was conducted to determine the effectiveness of lamivudine in preventing hepatocellular carcinoma (HCC). Of the 2795 patients who satisfied criteria for analysis after treatment from any of 30 medical institutions, 657 had received lamivudine and the remaining 2138 had not. A Cox regression model with liver biopsy as the starting point revealed seven factors related to HCC: lamivudine therapy, gender, family clustering of hepatitis B, age at liver biopsy, hepatic fibrosis stage, serum albumin level, and platelet count. In a matched case-controlled study, 377 patients in a lamivudine-treated group and 377 matched patients in a non-treated group were selected based on their propensity scores. The mean follow-up period was 2.7 years in the lamivudine group and 5.3 years in the control group. In the lamivudine group, HCC occurred in four patients (1.1%) with an annual incidence rate of 0.4%/(patient/year), whereas in the control group HCC occurred in 50 patients (13.3%) for a rate of 2.5%/(patient/year). A comparison of the cumulative HCC incidence between the two groups by the Kaplan-Meier method showed a significantly lower incidence of HCC in the lamivudine group (p<0.001). These findings suggest that lamivudine effectively reduces the incidence of HCC in patients with chronic hepatitis B.

Journal Article↗

PubMed2005

Reducing violence in serious juvenile offenders using intensive treatment.

This study reports on the reduction in violent offending in a population of serious and violent juvenile offenders following an intensive institutional treatment program. The treatment group (N=101) is compared to a similar group that was assessed but not treated (N=147). All youth were sent to the program from a juvenile corrections institution where they had received the customary rehabilitation services. The results show a significant reduction in the prevalence of recidivism in the treated group after controlling for time at risk in the community and other covariates. The effects of non-random group assignment were reduced by including a propensity score analysis procedure in the outcome analysis. Untreated comparison youth appeared to be about twice as likely to commit violent offenses as were treated youth (44% vs. 23%). Similarly, treated youth had significantly lower hazard ratios for recidivism in the in the community than the comparison youth, even after accounting for the effects of non-random group assignment.

Adolescent↗

PubMed2004

Angiotensin-converting enzyme inhibition in hypertensive patients is associated with a reduction in the occurrence of atrial fibrillation.

OBJECTIVE: The objective of this study was to determine the effects of angiotensin-converting enzyme inhibition (ACEI) versus long-acting calcium-channel blockade (CCB) on atrial fibrillation (AF) in patients with hypertension. BACKGROUND: Atrial fibrillation is the most common significant cardiac arrhythmia, and angiotensin II has been implicated in its pathophysiology. METHODS: This was a retrospective, longitudinal cohort study from a database of 8 million people in the U.S. Patients age > or =18 years with hypertension were eligible if they filled a prescription for either an ACEI or a CCB between January 1995 and June 1999. The use of all other antihypertensive medications was permitted. Patient chronic disease burden was assessed using a modified Charlson index. Patients were matched on a propensity score generated from a logistic regression model. A survival analysis approach was used to compare the incidence of AF between groups. The final cohorts were evaluated until June 2002, and the average follow-up was 4.5 years. RESULTS: After cohort matching, 10,926 patients were included in the analysis and divided equally into the ACEI and CCB groups. Mean patient age was 65 years. The adjusted hazards ratio (95% confidence interval [CI]) in the ACEI versus CCB groups for the entire follow-up period was 0.85 (95% CI: 0.74 to 0.97) for new-onset AF, and the adjusted incidence ratio for AF-related hospitalizations was 0.74 (95% CI: 0.62 to 0.89). CONCLUSIONS: Angiotensin-converting enzyme inhibition was associated with a reduced incidence of AF for patients with hypertension in a usual care setting. These results need to be confirmed in a large-scale randomized clinical trial.

Adolescent↗

PubMed2004

Cardiac rehabilitation after myocardial infarction in the community.

OBJECTIVES: The aim of this study was to examine participation in cardiac rehabilitation after myocardial infarction (MI) by age and gender and the association of participation with survival. BACKGROUND: Lesser participation in cardiac rehabilitation has been reported for women and the elderly. METHODS: All incident MIs in Olmsted County were validated. Baseline characteristics and outcomes were ascertained from the medical record. Logistic regression examined the association between participation, age, and gender. Propensity scores were used to examine the association between participation and outcome. RESULTS: Among 1,821 persons with incident MI (58% men, 46% age >70 years), 55% participated in cardiac rehabilitation. Participants were more likely to be men, younger, and have fewer comorbidities (p < 0.01 for all comparisons). After adjustment, women were 55% less likely to participate than men (odds ratio [OR] 0.45, 95% confidence interval [CI] 0.34 to 0.60), and persons 70 years or older were 77% less likely to participate than persons younger than 60 (OR 0.23, 95% CI 0.16 to 0.33). Participants had a lower risk of death and recurrent MI at three years (p < 0.001 and p = 0.049, respectively). The survival benefit associated with participation was stronger in more recent years (relative risk [RR] for 1998 vs. 1982 0.28, 95% CI 0.18 to 0.43; RR for 1990 vs. 1982 0.41, 95% CI 0.33 to 0.52). CONCLUSIONS: Approximately half of the patients participated in cardiac rehabilitation after MI. Participation did not increase over time. Women and elderly persons were less likely to participate, independently of other characteristics. Participation in rehabilitation was independently associated with decreased mortality and recurrent MI, and its protective effect was stronger in more recent years.

Age Factors↗

PubMed2005

Off-pump coronary artery surgery for reducing mortality and morbidity: meta-analysis of randomized and observational studies.

OBJECTIVES: The purpose of this study was to assess the effects of off-pump coronary bypass surgery (OPCAB) on mortality and morbidity. BACKGROUND: Despite its potential for reducing morbidity and mortality, OPCAB's role in clinical practice remains controversial. METHODS: A meta-analysis of 37 randomized controlled trials (RCTs) (n = 3,449) and 22 risk-adjusted (logistic regression or propensity-score) observational studies (n = 293,617) was performed. Two reviewers performed literature searches (MEDLINE, EMBASE, PubMed, reference lists), quality assessment, and data extraction. Treatment effects were calculated as odds ratios (ORs) with 95% confidence intervals (CIs). RESULTS: In RCTs, OPCAB was associated with reduced atrial fibrillation (OR 0.59; 95% CI 0.46 to 0.77) and trends toward reduced 30-day mortality (OR 0.91 95% CI 0.45 to 1.83), stroke (OR 0.52; 95% CI 0.25 to 1.05), and myocardial infarction (OR 0.79; 95% CI 0.50 to 1.25). Observational studies showed OPCAB to be associated with reduced 30-day mortality (OR 0.72; 95% CI 0.66 to 0.78), stroke (OR 0.62; 95% CI 0.55 to 0.69), infarction (OR 0.66; 95% CI 0.50 to 0.88), and atrial fibrillation (OR 0.78; 95% CI 0.74 to 0.82). At one to two years, OPCAB was associated with trends toward reduced mortality, but also increased repeat revascularization (RCT: OR 1.75, 95% CI 0.78 to 3.94; Observational: OR 1.35, 95% CI 0.76 to 2.39). CONCLUSIONS: Randomized controlled trials did not find, aside from atrial fibrillation, the statistically significant reductions in short-term mortality and morbidity demonstrated by observational studies. These discrepancies might be due to differing patient-selection and study methodology. Future studies must focus on improving research methodology, recruiting high-risk patients, and collecting long-term data.

Acute Kidney Injury↗

PubMed2006

Troponin-T and N-terminal pro-B-type natriuretic peptide predict mortality benefit from coronary revascularization in acute coronary syndromes: a GUSTO-IV substudy.

OBJECTIVES: This study was designed to evaluate biomarkers for selection of patients with non-ST-segment elevation acute coronary syndromes (ACS) that derive mortality benefit from revascularization. BACKGROUND: Biomarkers are essential for identification of patients at increased risk, which may be reduced by revascularization. METHODS: During the initial 30 days, 2,340 patients of 7,800 (30%) with non-ST-segment elevation ACS in the GUSTO (Global Utilization of Strategies To open Occluded arteries)-IV trial underwent coronary revascularization. The 1-year mortality was calculated in 30-day survivors stratified by status of revascularization and levels of biomarkers. A propensity score for receiving revascularization was constructed and included in a survival analysis that also included the time point of revascularization as a time-dependent covariate. RESULTS: Elevation of troponin-T or N-terminal pro-B-type natriuretic peptide (NT-proBNP) was associated with a high mortality. In patients with either or both of these markers elevated, a lower mortality following revascularization was observed. In contrast, patients without elevation of these markers had low 1-year mortality without any reduction in mortality following revascularization. In fact, in patients with normal levels of both troponin-T and NT-proBNP, a significant increase in 1-year mortality after revascularization was observed. Elevation of C-reactive protein, interleukin-6, creatinine clearance, and ST-segment depression was also related to a higher mortality. However, independent of these markers, mortality was lower after revascularization. CONCLUSIONS: Markers of troponin-T and NT-proBNP not only assist in risk stratification of patients with non-ST-segment elevation ACS but also appear to identify patients who have a reduced mortality associated with early coronary revascularization.

Acute Disease↗

PubMed2006

Methods to adjust for bias and confounding in critical care health services research involving observational data.

Observational data are often used for research in critical care. Unlike randomized controlled trials, where randomization theoretically balances confounding factors, studies involving observational data pose the challenge of how to adjust appropriately for the bias and confounding that are inherent when comparing two or more groups of patients. This paper first highlights the potential sources of bias and confounding in critical care research and then reviews the statistical techniques available (matching, stratification, multivariable adjustment, propensity scores, and instrumental variables) to adjust for confounders. Finally, issues that need to be addressed when interpreting the results of observational studies, such as residual confounding, causality, and missing data, are discussed.

Bias↗