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Results for “Propensity Score”

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PubMed2006

The effect of statins on urinary albumin excretion and glomerular filtration rate: results from both a randomized clinical trial and an observational cohort study.

BACKGROUND: Statins improve cardiovascular outcome, but less is known on the renal outcome. We, therefore, studied the relationship between the use of statins and urinary albumin excretion (UAE) and glomerular filtration rate (GFR) in two settings: a randomized controlled trial (RCT) and an observational cohort study, in which patients were included to study the impact of an elevated UAE on renal and cardiovascular prognosis. METHODS: We used data from the Prevention of REnal and Vascular ENd-stage Disease Intervention trial (PREVEND-IT) and the PREVEND cohort study. The PREVEND-IT subjects (788 with a UAE 15-300 mg/day) received pravastatin 40 mg/day vs placebo and/or fosinopril 20 mg/day vs placebo in a 2x2 factorial-RCT design. Of the 3440 cohort subjects, 469 used statins during the 4-year follow-up period. Multivariate-regression adjusted for confounding factors and the propensity score was used to estimate the relation between statin use and UAE and GFR. RESULTS: In the RCT, pravastatin did not change UAE or GFR, neither in fosinopril yes/no subgroups. In the observational cohort, statin use was associated with a rise in UAE (+12.1%), compared with statin non-use (+3.6%, P<0.001). This rise was most pronounced in those on statins prior to the first screening [+24.8% (95% CI: 11.9-39.2)], those using statins>3 years [+18.5% (7.3-30.8)] and those with >1 or >2 defined daily doses (+15.7 and +17.3%, respectively). These differences remained significant after adjustment for relevant variables and propensity score. The rise in UAE could not be attributed to a higher dose or a specific statin. GFR fell in 4 years in both statin users and non-users (4.6+/-13.5 and 2.4+/-11.2, respectively). The fall in GFR between groups was not different after adjustment (P=0.11). CONCLUSIONS: We conclude from the RCT data that statins do not lower UAE in subjects selected because of an elevated UAE instead of hyperlipidaemia. In the observational cohort study, the use of statins similarly was not associated with a fall in UAE; UAE instead increased. Statin treatment was not associated with a significant change in GFR in these subjects with only modestly impaired GFR.

Adult↗

PubMed2003

Treatment of locally advanced pancreatic cancer in the real world: population-based practices and effectiveness.

PURPOSE: To evaluate the use and effectiveness of cancer-directed therapy in elderly patients with locally advanced pancreatic cancer (LAPC). METHODS: We used the linked Surveillance, Epidemiology, and End Results Medicare database to perform a retrospective cohort study in 1,696 patients diagnosed with LAPC between 1991 and 1996. We calculated cancer-directed treatment use rates, then used logistic regression to identify patient and health system factors that were associated with receipt of treatment. Effectiveness of treatment was estimated using Cox proportional hazards models and propensity score methods. RESULTS: In our cohort, 44% of patients received some form of cancer-directed therapy (24% radiation with concurrent chemotherapy, 13% radiation alone, and 7% chemotherapy alone). Older age, lower socioeconomic status, presence of comorbid illness, no care in a teaching hospital, and residence in the western United States were associated with a lower likelihood of receiving treatment (P </=.05). Among those treated, younger age and certain geographic locations were the only predictors of receiving combined-modality therapy. The adjusted hazard ratio for death associated with any treatment in the Cox model was 0.53 (P <.0001). Effectiveness estimates obtained using propensity score methods were similar. CONCLUSION: This analysis supports the effectiveness of cancer-directed treatment in elderly patients with LAPC, but use is low. Receipt of treatment is strongly correlated with non-disease-related factors, especially sociodemographic characteristics, indicating possible disparities in access to care.

Adenocarcinoma↗

PubMed2005

A matched-cohort study of health services utilization outcomes for a heart failure disease management program.

Chronic disease is the leading cause of illness, disability, and death in the United States, affecting nearly 100 million Americans. Heart failure alone affects nearly 4.9 million Americans, with another 550,000 newly diagnosed cases each year. The aim of this study was to investigate the program effects of a heart failure care support program. A two-group cohort study matching on propensity scores was used to investigate 277 heart failure care support program participants and corresponding matched non-participants. Measures used were rates of hospitalizations, emergency department visits, physician office visits, and heart failure-related prescription drug use and procedures. Relative to the matched control group, program participants experienced 26.3% (p = 0.023) fewer inpatient admissions, 37.9% (p = 0.018) inpatient bed days, 33.3% (p = 0.059) more beta blocker use, 76.7% (p = 0.048) more alpha blocker use, 22.2% (p = 0.006) more lipid panels, 13.4% (p = 0.019) more electrocardiographies, 50.0% (p = 0.008) fewer cardiac catheterizations, and 94.6% (p = 0.014) more pneumonia vaccinations. The current study employs a propensity score matching methodology to select a subset of comparison patients most comparable to treatment patients, and documents the beneficial health services outcomes of participation in a heart failure care support program.

Aged↗

PubMed2004

A dissection of specific and non-specific protein-protein interfaces.

We compare the geometric and physical-chemical properties of interfaces involved in specific and non-specific protein-protein interactions in crystal structures reported in the Protein Data Bank. Specific interactions are illustrated by 70 protein-protein complexes and by subunit contacts in 122 homodimeric proteins; non-specific interactions are illustrated by 188 pairs of monomeric proteins making crystal-packing contacts selected to bury more than 800 A2 of protein surface. A majority of these pairs have 2-fold symmetry and form "crystal dimers" that cannot be distinguished from real dimers on the basis of the interface size or symmetry. The chemical and amino acid compositions of the large crystal-packing interfaces resemble the protein solvent-accessible surface. These interfaces are less hydrophobic than in homodimers and contain much fewer fully buried atoms. We develop a residue propensity score and a hydrophobic interaction score to assess preferences seen in the chemical and amino acid compositions of the different types of interfaces, and we derive indexes to evaluate the atomic packing, which we find to be less compact at non-specific than at specific interfaces. We test the capacity of these parameters to identify homodimeric proteins in crystal structures, and show that a simple combination of the non-polar interface area and the fraction of buried interface atoms assigns the quaternary structure of 88% of the homodimers and 77% of the monomers in our data set correctly. These success rates increase to 93-95% when the residue propensity score of the interfaces is taken into consideration.

Databases, Protein↗

PubMed2003

Inappropriate initial antimicrobial therapy and its effect on survival in a clinical trial of immunomodulating therapy for severe sepsis.

PURPOSE: To examine the effect of inappropriate initial antimicrobial therapy on the prognosis of patients with sepsis who were enrolled in a clinical trial of an immunomodulating agent conducted in 108 hospitals in North America and Europe. METHODS: We assessed initial antimicrobial choice and results of microbiologic cultures in 904 patients who had microbiologically confirmed severe sepsis or early septic shock. If a patient did not receive at least one antimicrobial agent to which the causative microorganisms were susceptible within 24 hours from the diagnosis of severe sepsis, then the initial antimicrobial treatment was considered to be inappropriate. A propensity score that adjusted for factors associated with inappropriate antimicrobial treatment was calculated and included in multivariable models to adjust for confounding. RESULTS: A total of 468 patients (52%) had documented bloodstream infection, and 211 patients (23%) received inappropriate initial antimicrobial therapy. Characteristics associated with inappropriate treatment were study enrollment in Europe, admission to surgery, nosocomial infection, infection with multiresistant microorganisms, and fungal or polymicrobial infection (all P <0.05). The 28-day mortality was 24% (168/693) for patients in the adequately treated group versus 39% (82/211) for patients receiving inappropriate initial antimicrobial therapy (P <0.001). After adjusting for comorbid conditions, severity of illness, site of infection, and the propensity score, inappropriate antimicrobial therapy was independently associated with increased mortality (odds ratio = 1.8; 95% confidence interval: 1.2 to 2.6). CONCLUSION: In a large cohort of patients with microbiologically confirmed severe sepsis, appropriate initial antimicrobial therapy was an important determinant of survival. New approaches aimed at improving detection and treatment of early sepsis are needed.

Aged↗

PubMed2006

Cardioprotective medication is associated with improved survival in patients with peripheral arterial disease.

OBJECTIVES: We sought to investigate the effect of cardiac medication on long-term mortality in patients with peripheral arterial disease (PAD). BACKGROUND: Peripheral arterial disease is associated with increased cardiovascular morbidity and mortality. Treatment guidelines recommend aggressive management of risk factors and lifestyle modifications. However, the potential benefit of cardiac medication in patients with PAD remains ill defined. METHODS: In this prospective observational cohort study, 2,420 consecutive patients (age, 64 +/- 11 years, 72% men) with PAD (ankle-brachial index < or =0.90) were screened for clinical risk factors and cardiac medication. Follow-up end point was death from any cause. Propensity scores for statins, beta-blockers, aspirin, angiotensin-converting enzyme (ACE) inhibitors, calcium channel blockers, diuretics, nitrates, coumarins, and digoxin were calculated. Cox regression models were used to analyze the relation between cardiac medication and long-term mortality. RESULTS: Medical history included diabetes mellitus in 436 patients (18%), hypercholesterolemia in 581 (24%), smoking in 837 (35%), hypertension in 1,162 (48%), coronary artery disease in 1,065 (44%), and a history of heart failure in 214 (9%). Mean ankle-brachial index was 0.58 (+/-0.18). During a median follow-up of eight years, 1,067 patients (44%) died. After adjustment for risk factors and propensity scores, statins (hazard ratio [HR] 0.46, 95% confidence interval [CI] 0.36 to 0.58), beta-blockers (HR 0.68, 95% CI 0.58 to 0.80), aspirins (HR 0.72, 95% CI 0.61 to 0.84), and ACE inhibitors (HR 0.80, 95% CI 0.69 to 0.94) were significantly associated with a reduced risk of long-term mortality. CONCLUSIONS: On the basis of this observational longitudinal study, statins, beta-blockers, aspirins, and ACE inhibitors are associated with a reduction in long-term mortality in patients with PAD.

Atherosclerosis↗

PubMed2006

International INtegrated Database for the Evaluation of severe sePsis and drotrecogin alfa (activated) THerapy: component trials and statistical methods for INDEPTH.

OBJECTIVES: To better understand the effects of drotrecogin alfa (activated) (DrotAA) in severe sepsis patients, and the natural progression of severe sepsis, by creating a database of severe sepsis patients using the appropriate statistical analysis methods to integrate data from various trials. PATIENTS AND METHODS: Patient-level data from five severe sepsis trials, conducted by the same sponsor (Eli Lilly and Company, Indianapolis, IN, USA), were combined in an integrated database. Patients from various studies were included and received either DrotAA at 24 microg/kg/h for 96 hours (n = 3228) or placebo (n = 1231), in addition to standard supportive care. The following adjustments to the analyses were made to allow for the combined, and thus non-randomized, nature of the data: (1) differences in observed outcomes between studies were investigated to assess the extent of study-to-study variation before combining study-level data across trials for statistical analysis; (2) random study effects were included in models for patient-level data to capture potential extraneous study-to-study variation; and (3) propensity scores were computed and included as covariates in models for patient-level data to adjust for the nonrandomized nature of the data. RESULTS: Baseline characteristics were similar across the studies, supporting the combination of study-level data across trials. Comparing aggregate event rates between the two treatment arms yielded a relative risk for mortality (DrotAA versus placebo) of 0.79 (95% confidence interval [CI] 0.71-0.88), p < 0.0001. For patient-level analyses, after adjustment for 13 independent variables and random study effects, the odds ratio for mortality in the DrotAA versus placebo patients was 0.71 (95% CI 0.59-0.86), p = 0.0003. With adjustment for 13 independent variables and propensity score, the odds ratio was 0.79 (95% CI 0.67-0.93), p = 0.006. Limitations of this integrated database include the modest total number of the trials in the database and the fact that only one component trial in the database contributed data from both placebo and DrotAA-treated patients. SUMMARY: A robust severe sepsis database was developed which will be suitable for future studies on the progression of severe sepsis and the mechanism of action of DrotAA. Initial analysis of data from INDEPTH provides additional evidence that treatment of severe sepsis patients with DrotAA is associated with a sustained survival advantage throughout 28-day follow-up.

Aged↗

PubMed2004

Coronary surgery in patients with peripheral vascular disease: effect of avoiding cardiopulmonary bypass.

BACKGROUND: An increasing number of patients with peripheral vascular disease are undergoing coronary artery bypass grafting. Such patients have an increased risk of adverse outcomes. Our aim was to quantify the effect of avoiding cardiopulmonary bypass in this group of patients. METHODS: Between April 1997 and March 2002, 3,771 consecutive patients underwent coronary artery bypass grafting performed by five surgeons. Four hundred and twenty-two (11.2%) had peripheral vascular disease and of these, 211 (50%) received off-pump surgery. We used multivariate logistic regression analysis to assess the effect of off-pump surgery on in-hospital mortality and morbidity, while adjusting for treatment selection bias. Treatment selection bias was controlled for by constructing a propensity score, which was the probability of receiving off-pump surgery and included core patient characteristics. The C statistic for this model was 0.8. RESULTS: Off-pump patients were more likely to have preoperative renal dysfunction, previous gastrointestinal surgery, and less extensive disease. The left internal mammary artery was used more in off-pump compared to on-pump cases (90.1% vs 82.9%; p = 0.033). In the univariate analyses, off-pump patients were less likely to have a postoperative stroke (p = 0.007), and had shorter postoperative hospital stays (p < 0.001). However, the incidence of new atrial arrhythmia was higher (p = 0.028). After adjustment for differences in case-mix (propensity score), avoidance of cardiopulmonary bypass was still associated with a significant reduction in postoperative stroke (adjusted odds ratio 0.09 [95% confidence interval 0.02 to 0.50]; p = 0.005), and shorter postoperative hospital stay (p = 0.001). CONCLUSIONS: Off-pump coronary surgery is safe in patients with peripheral vascular disease, with acceptable results. The incidence of postoperative stroke is substantially reduced when avoiding cardiopulmonary bypass in patients with peripheral vascular disease.

Aged↗

PubMed2002

Nephrology consultation in acute renal failure: does timing matter?

PURPOSE: Patients who develop acute renal failure in the intensive care unit (ICU) have extremely high rates of mortality and morbidity. The goals of this study were to identify correlates of the timing of nephrology consultation in acute renal failure, and to explore the relation between timing of consultation and outcomes. METHODS: We explored associations among timing of nephrology consultation and in-hospital mortality, lengths of hospital and ICU stay, and recovery of renal function in 215 ICU patients with acute renal failure at four U.S. teaching hospitals. We used multivariable logistic regression and propensity scores to adjust for confounding and selection effects. RESULTS: Nephrology consultation was delayed (>or=48 hours) in 61 patients (28%) (median time to consultation, 4 days). Lower serum creatinine levels (P <0.0001) and higher urine output (P = 0.002) were associated with delayed consultation. Delayed consultation was associated with increased mortality among dialyzed (31/42 [74%] vs. 50/103 [49%], P = 0.006) and nondialyzed patients (10/19 [53%] vs. 11/51 [22%], P = 0.01), and increases in lengths of hospital (median, 19 days vs. 16 days, P = 0.01) and ICU stay (17 days vs. 6 days, P <0.0001). The association between delayed consultation and mortality was attenuated by covariate adjustment, and was no longer statistically significant after adjustment for propensity score (odds ratio = 2.0; 95% confidence interval: 0.8 to 5.1). CONCLUSION: In acute renal failure, delayed nephrology consultation was associated with increased mortality and morbidity, whether or not dialysis was ultimately required. Using observational data, we cannot determine whether these findings reflect residual confounding, selection bias, adverse effects of delayed recognition of acute renal failure, or the benefits of nephrology consultation.

Acute Kidney Injury↗

PubMed2005

Biological versus mechanical aortic prosthesis? A nineteen-year comparison in a propensity-matched population.

BACKGROUND AND AIM OF THE STUDY: The choice of aortic valve substitutes remains controversial. Malfunction and systemic valve complications affect the results of mechanical and tissue valves. Two devices--the Sorin Monocast (tilting disk) valve and the Hancock Standard valve were compared, the study aim being to determine whether the valve model is a marker or a causal influence of poor outcome after aortic valve replacement (AVR). METHODS: Between January 1970 and January 1984, patients aged < 70 years and operated on for aortic valve disease were selected. A total of 379 patients received either Sorin (group S) valves (n = 213; median age 51 years) or Hancock Standard (group HcK) valves (n = 192; median age 50 years) (p = NS). Total follow up was 2,471 patient-years (pt-yr) for group S and 2,368 pt-yr for group HcK. Follow up was 98% complete; median duration was 15 pt-yr for group S and 13.2 pt-yr for group HcK. Propensity matching for available patient intrinsic and operative risk factors was ultimately used to investigate whether biological or mechanical valve models impact upon outcome after aortic valve surgery. Patient survival was analyzed according to the 'intention to treat' principle. RESULTS: The 30-day mortality was 7.5% for group S and 10.9% for group HcK (p = NS). The 19-year Kaplan-Meier freedom from valve-related mortality was 84% (group S) and 82% (group HcK) (p = NS), while overall survival was 42% (group S) and 35% (group HcK) (p = NS). Structural valve deterioration (SVD) was the major cause of reoperation in the HcK group. The 19-year freedom from all valve-related complications was 43% (group S) versus 19% (group HcK) (p = 0.0001). By propensity score, 61% of the valve replacements (247/405) were perfectly matched for available risk factors, with an equal distribution of risk covariates. When SVD and reoperation due to SVD were excluded, survival and freedom from all valve-related complications of the matched patients were identical between the prostheses under comparison. CONCLUSION: In this relatively young population, the Sorin valve showed a significantly lower valve-related complication rate than the Hancock Standard valve. The latter valve showed a significantly increasing rate of reoperation due to SVD, and thereby a relative inadequacy for use in younger patients. When analyzed according to an 'intention to treat' principle, the 19-year survival and freedom from valve-related complications of patients with the same propensity score for selection of either valve type were similar.

Adolescent↗

PubMed2005

The association between prior percutaneous coronary intervention and short-term outcomes after coronary artery bypass grafting.

BACKGROUND: Increasingly, patients are being referred for coronary artery bypass grafting (CABG) for management of symptoms after prior percutaneous coronary intervention (PCI). In this study, we assessed the impact of prior PCI on inhospital mortality after CABG. METHODS: Perioperative data were collected on patients who underwent first-time CABG at 2 surgical centers. Patients who underwent PCI and CABG during the same admission were excluded. Patients with prior PCI were compared with patients with no prior PCI, and the risk-adjusted impact of prior PCI on inhospital mortality after CABG was determined using both multivariate techniques and propensity score matching techniques. RESULTS: Six thousand thirty-two patients met inclusion criteria. Patients with prior PCI were less likely to be between the ages of 70 and 80 (P < .0001), to have an ejection fraction <0.40 (P < .0001), and to have 3-vessel/left main disease (P < .0001). They were, however, more likely to have Canadian Cardiovascular Society class IV symptoms (P < .0001) and to have an urgent status (P = .02). Rates of inhospital mortality after CABG were higher in patients with prior PCI (3.6% vs 2.3%, P = .02). Using multivariate techniques, prior PCI emerged as an independent predictor of postoperative inhospital mortality (odds ratio 1.93, P = .003). When patients with prior PCI were matched to patients with no prior PCI using propensity scores, inhospital mortality remained higher among patients with prior PCI (3.6% vs 1.7%, P = .01). CONCLUSION: Patients with prior PCI presented for CABG with less comorbidity and diminished coronary disease; yet, they had more advanced symptoms and greater urgency. After adjusting for these differences, prior PCI emerged as an independent predictor of inhospital mortality after CABG.

Aged↗

PubMed2005

Postmastectomy radiation and mortality in women with T1-2 node-positive breast cancer.

PURPOSE: To determine the relationship between postmastectomy radiotherapy (PMRT) and mortality in a population-based cohort of women with T1-2 node-positive breast cancer. PATIENTS AND METHODS: Using data from the Surveillance, Epidemiology, and End Results program, we identified 18,038 women with T1-2 node-positive invasive breast cancer who were treated with mastectomy between 1988 and 1995. The relationship between PMRT and mortality was determined using proportional hazards multivariate modeling and propensity score matched case-control analysis. RESULTS: Median follow-up was 8.1 years. Only 2,648 women (15%) received PMRT. After adjusting for covariates, PMRT use was not associated with mortality (hazard ratio [HR] = 0.96; 95% CI, 0.90 to 1.03). However, the interaction term for PMRT use and number of involved regional lymph nodes was significant (P = .002), suggesting that, above a certain threshold of involved nodes, a mortality benefit from PMRT may exist. Adjusted analysis stratified by number of involved nodes revealed that patients with seven or more involved nodes treated with PMRT experienced a significant reduction in all-cause (HR = 0.84; 95% CI, 0.76 to 0.93) and cause-specific mortality (HR = 0.86; 95% CI, 0.77 to 0.96). Propensity score matched case-control analysis confirmed that PMRT was associated with reduced mortality only in the subset of patients with seven or more involved nodes (HR = 0.81; 95% CI, 0.73 to 0.91 for all-cause mortality; and HR = 0.82; 95% CI, 0.72 to 0.93 for cause-specific mortality). CONCLUSION: For women with T1-2 breast cancer, PMRT is associated with a 15% to 20% relative reduction in mortality for patients with seven or more involved regional lymph nodes.

Aged↗

PubMed2004

Comparison of coronary bypass surgery with and without cardiopulmonary bypass in patients with multivessel disease.

BACKGROUND: Coronary artery bypass grafting can now be performed with or without cardiopulmonary bypass. Our objective was to determine whether off-pump coronary artery bypass grafting is associated with better early outcomes compared with conventional coronary artery bypass grafting. METHODS: In 4 centers with off-pump coronary surgery experience, a retrospective analysis of all coronary artery bypass grafting in a 3-year period was performed. Groups were compared to determine selection criteria, mortality, and morbidity, then computer-matched by propensity score to control for selection bias. Multivariate logistic regression identified risk factors predictive of mortality. Specific subgroups most likely to benefit were identified. RESULTS: In all, 17,401 isolated coronary artery bypass grafts were performed, 7283 (41.9%) off-pump coronary artery bypass grafts and 10,118 (58.1%) conventional coronary artery bypass with cardiopulmonary bypass. Factors determining selection of patients for off-pump coronary artery bypass grafting included female gender (55.5% vs 44.5%), preexisting renal failure (57.0% vs 43.0%), and reoperations (52.6% vs 47.4%). Operative mortality was 2.8%; off-pump coronary artery bypass grafting versus conventional coronary artery bypass with cardiopulmonary bypass (1.9% vs 3.5%, P <.001) had the same predicted risk. Of the patients with multivessel disease, 11,548 were matched by propensity scoring. Mortality was significantly less in the off-pump coronary artery bypass grafting group (2.8% vs 3.7%, P <.001). By multivariate logistic regression analysis of the matched sample, predictors for mortality were female gender (odds ratio 1.83, confidence interval 1.37-2.44), preexisting renal failure (odds ratio 2.85, confidence interval 2.64-4.95), history of stroke (odds ratio 1.74, confidence interval 1.08-2.80), previous coronary artery bypass grafting surgery (odds ratio 4.22, confidence interval 2.92-6.09), use of cardiopulmonary bypass (odds ratio 2.08, confidence interval 1.52-2.83), and recent myocardial infarction (odds ratio 2.31, confidence interval 1.68-3.22). Cardiopulmonary bypass was predictive of mortality in reoperations, female patients, and patients aged >or= 75 years. Off-pump coronary artery bypass grafting was associated with less morbidity, including reductions in blood transfusion (32.6% vs 40.6%, P <.001), stroke (1.4% vs 2.1%, P =.002), renal failure (2.6% vs 5.2%, P <.001), pulmonary complications (4.1% vs 9.5%, P <.001), reoperation (1.7% vs 3.2%, P <.001), atrial fibrillation (21.1% vs 24.99%, P <.001), and gastrointestinal complications (3.6% vs 4.8%, P =.02). CONCLUSION: In 4 centers with beating-heart operation experience, there is an overall early benefit in off-pump surgery, especially in patients traditionally considered at high risk for coronary artery bypass grafting.

Adult↗

PubMed2005

Effect of the left internal mammary artery to the left anterior descending artery on mortality and morbidity after combined coronary and valve operations.

BACKGROUND: The effect of using the left internal mammary artery in combined coronary and valve operations have not been fully investigated. We aimed to quantify the impact of the left internal mammary artery to the left anterior descending artery on early and mid-term outcomes in these patients. METHODS: Data was collected prospectively on 630 consecutive patients who underwent revascularization of the left anterior descending artery with concomitant valve operations between April 1997 and March 2003. Multivariate logistic regression and Cox proportional hazards analyses were used to adjust in-hospital outcomes and Kaplan-Meier survival curves. A propensity score for left internal mammary artery use was constructed to control for selection bias. RESULTS: The left internal mammary artery was used in 478 (75.9%) patients. Univariate analyses found left internal mammary artery patients had significantly lower in-hospital mortality (6.3% versus 13.2%; p < 0.01) and postoperative renal failure (8.2% versus 13.8%; p = 0.038). After adjusting for treatment selection bias, in-hospital mortality (adjusted odds ratio, 0.77; p = 0.45) and renal failure (adjusted odds ratio, 0.94; p = 0.86) were no longer significantly different. A total of 171 (27.1%) deaths occurred during the follow-up, with a total follow-up of 2,325 patient-years. The crude relative risk for the left internal mammary artery was 0.67 (p = 0.015). After adjusting for the propensity score, the adjusted relative risk was 0.91 (p = 0.62). CONCLUSIONS: The left internal mammary artery does not adversely affect the short-term and medium-term outcomes in patients undergoing concomitant coronary and valve operations. Survival at 7 years was similar with or without the use of the left internal mammary artery.

Aged↗

PubMed1998

Splenectomy and risk of blast transformation in myelofibrosis with myeloid metaplasia. Italian Cooperative Study Group on Myeloid with Myeloid Metaplasia.

An unexpectedly high incidence of blast transformation after splenectomy has been reported in patients with myelofibrosis with myeloid metaplasia. However, whether this was associated with spleen removal after adjustment for risk factors was not determined. We conducted a multicenter historical cohort study of patients with myelofibrosis with myeloid metaplasia diagnosed from January 1970 through January 1994. A total of 549 patients (325 men and 224 women from 22 to 92 years of age; median age, 63 years) were included in the final data set. The Cox's proportional-hazards model was used to identify factors associated with blast transformation and death. To further adjust for factors related to spleen removal assignment, a propensity score for splenectomy was estimated using recursive-partitioning analysis. Blast transformation developed in 78 patients (14.2%). Patients who underwent splenectomy developed more blast transformations than those who were not splenectomized (23 of 87 [26.4%] v 55 of 462 [11.9%]; P < .001). The cumulative incidence of blast transformation 12 years after diagnosis was 27.0% in nonsplenectomized patients and 55.0% in splenectomized ones (P = . 01). The risk factors independently predictive of blast transformation included prior splenectomy (relative risk = 2.61), platelet count less than 100 x 10(9)/L at diagnosis (relative risk = 2.45), and the presence of blasts in peripheral blood at diagnosis (relative risk = 2.31). The relative risk of blast transformation in splenectomized patients increased from 2.2 at 48 months from diagnosis to 14.3 at 12 years. Patients with the same propensity score for splenectomy showed a higher risk for blast transformation on the basis of having undergone splenectomy (P = .02). In conclusion, the risk of blast transformation is significantly increased in subjects who underwent splenectomy and appears to be independent of factors related to spleen removal assignment.

Adult↗

PubMed2006

Clinical outcomes of nonelective coronary revascularization with and without cardiopulmonary bypass.

BACKGROUND: Patients who undergo emergent coronary artery bypass grafting pose a greater challenge in terms of intraoperative and postoperative mortality and morbidity compared to elective coronary artery bypass. Coronary artery bypass without cardiopulmonary bypass (off-pump coronary artery bypass) might benefit these high-risk patients by eliminating the cardiopulmonary bypass and therefore decreasing the systemic inflammatory response associated with it. The aim of this study was to compare the early clinical outcome after nonelective off-pump coronary artery bypass with a matched set of patients undergoing coronary artery bypass with cardiopulmonary bypass (on pump). METHODS: Between January 2000 and October 2003, 2273 patients underwent nonelective (urgent or emergent) off-pump coronary artery bypass and were compared with a contemporaneous control group of 3487 patients undergoing on-pump coronary artery bypass. Logistic regression analysis was used to compare operative mortality, postoperative stroke, length of stay, postoperative placement of intra-aortic balloon pump, postoperative renal failure, and hemorrhage-related re-exploration between the groups, controlling for preoperative risk factors. The patients undergoing off-pump coronary artery bypass were matched to patients undergoing on-pump bypass by propensity scores. RESULTS: Patients undergoing off-pump coronary artery bypass had comparable operative mortality (odds ratio, 0.8; 95% confidence interval, 0.57-1.15; P = .24) and stroke rate (odds ratio, 0.6; 95% confidence interval, 0.33-1.08; P = .09) with the patients undergoing on-pump coronary artery bypass after controlling for preoperative risk factors through matching. Off-pump coronary artery bypass was associated with an abbreviated length of stay (odds ratio, 0.5; 95% confidence interval, 0.47-0.64; P < .01), lower rate of postoperative renal failure (odds ratio, 0.5; 95% confidence interval, 0.37-0.72; P < .01), intra-aortic balloon pump placement (odds ratio, 0.5; 95% confidence interval, 0.3-0.71; P < .01), and hemorrhage-related re-exploration rate (odds ratio, 0.70; 95% confidence interval, 0.5-1.0; P = .5) compared with on-pump coronary artery bypass after matching by propensity scores. CONCLUSIONS: Nonelective coronary revascularization without cardiopulmonary bypass is associated with comparable operative mortality and stroke and abbreviated length of stay. Off-pump coronary artery bypass might also decrease the need for intra-aortic balloon pump placement and lower the rate of postoperative renal failure and hemorrhage-related re-exploration compared with that of conventional on-pump coronary artery bypass in this subset of patients.

Aged↗

PubMed2005

Risk of death in elderly users of conventional vs. atypical antipsychotic medications.

BACKGROUND: Recently, the Food and Drug Administration (FDA) issued an advisory stating that atypical antipsychotic medications increase mortality among elderly patients. However, the advisory did not apply to conventional antipsychotic medications; the risk of death with these older agents is not known. METHODS: We conducted a retrospective cohort study involving 22,890 patients 65 years of age or older who had drug insurance benefits in Pennsylvania and who began receiving a conventional or atypical antipsychotic medication between 1994 and 2003. Analyses of mortality rates and Cox proportional-hazards models were used to compare the risk of death within 180 days, less than 40 days, 40 to 79 days, and 80 to 180 days after the initiation of therapy with an antipsychotic medication. We controlled for potential confounding variables with the use of traditional multivariate Cox models, propensity-score adjustments, and an instrumental-variable analysis. RESULTS: Conventional antipsychotic medications were associated with a significantly higher adjusted risk of death than were atypical antipsychotic medications at all intervals studied (< or =180 days: relative risk, 1.37; 95 percent confidence interval, 1.27 to 1.49; <40 days: relative risk, 1.56; 95 percent confidence interval, 1.37 to 1.78; 40 to 79 days: relative risk, 1.37; 95 percent confidence interval, 1.19 to 1.59; and 80 to 180 days: relative risk, 1.27; 95 percent confidence interval, 1.14 to 1.41) and in all subgroups defined according to the presence or absence of dementia or nursing home residency. The greatest increases in risk occurred soon after therapy was initiated and with higher dosages of conventional antipsychotic medications. Increased risks associated with conventional as compared with atypical antipsychotic medications persisted in confirmatory analyses performed with the use of propensity-score adjustment and instrumental-variable estimation. CONCLUSIONS: If confirmed, these results suggest that conventional antipsychotic medications are at least as likely as atypical agents to increase the risk of death among elderly persons and that conventional drugs should not be used to replace atypical agents discontinued in response to the FDA warning.

Aged↗

PubMed2004

Association of timing of surgery for hip fracture and patient outcomes.

CONTEXT: Previous studies of surgical timing in patients with hip fracture have yielded conflicting findings on mortality and have not focused on functional outcomes. OBJECTIVE: To examine the association of timing of surgical repair of hip fracture with function and other outcomes. DESIGN: Prospective cohort study including analyses matching cases of early (< or =24 hours) and late (>24 hours) surgery with propensity scores and excluding patients who might not be candidates for early surgery. SETTING: Four hospitals in the New York City metropolitan area. PARTICIPANTS: A total of 1206 patients aged 50 years or older admitted with hip fracture over 29 months, ending December 1999. MAIN OUTCOME MEASURES: Function (using the Functional Independence Measure), survival, pain, and length of stay (LOS). RESULTS: Of the patients treated with surgery (n = 1178), 33.8% had surgery within 24 hours. Earlier surgery was not associated with improved mortality (hazard ratio, 0.75; 95% confidence interval [CI], 0.52-1.08) or improved locomotion (difference of -0.04 points; 95% CI, -0.49 to 0.39). Earlier surgery was associated with fewer days of severe and very severe pain (difference of -0.22 days; 95% CI, -0.41 to -0.03) and shorter LOS by 1.94 days (P<.001), but postoperative pain and LOS after surgery did not differ. Analyses with propensity scores yielded similar results. When the cohort included only patients who were medically stable at admission and therefore eligible for early surgery, the results were unchanged except that early surgery was associated with fewer major complications (odds ratio, 0.26; 95% CI, 0.07-0.95). CONCLUSIONS: Early surgery was not associated with improved function or mortality, but it was associated with reduced pain and LOS and probably major complications among patients medically stable at admission. Additional research is needed on whether functional outcomes may be improved. In the meantime, patients with hip fracture who are medically stable should receive early surgery when possible.

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