Propensity Score-adjusted Regression Models Research Articles

Chlorhexidine bathing in a tertiary care neonatal intensive care unit: A pilot study.

Concerns regarding potential risk of dermal irritation have led to the exclusion of NICU patients from the recommendation regarding the use of 2% chlorhexidine gluconate (CHG) wash for daily skin cleansing to reduce bloodstream infections. Our aim was to assess the safety of 2% CHG bathing in NICU patients. The regulator required a stepwise study enrollment to three successive groups: term infants, followed by near-term and pre-term infants. For comparison, we used a cohort of matched controls. A propensity score-adjusted regression model was used to compare the groups. Infants were bathed thrice-weekly with 2% CHG-impregnated washcloths. Participant's skin was examined daily. Over a total of 661 days of treatment: 384,129, and 148 days for the term, near-term and pre-term groups, respectively, no skin reactions were observed. The intervention group was generally sicker, however, bloodstream infections were similar between the groups. For infants >30 weeks and >3 days old, 2% CHG bathing was safe. Large multicenter studies are urgently needed to establish the effectiveness of this practice in the NICU.

Treatment of extensively-drug resistant (XDR) Acinetobacter and impact on clinical outcomes in U.S. veterans affairs (VA) medical centers

BackgroundGuidelines for treatment of resistant Acinetobacter baumannii (AB) are limited, leaving a knowledge gap in best practices for treatment. This study described treatments and outcomes of extensively-drug resistant (XDR) AB. MethodsRetrospective cohort study including patients with XDRAB (non-susceptible to at least 1 agent in all but 2 or fewer classes) and antibiotic treatment between 2012 and 2018 at Veterans Affairs Medical Centers. Descriptive statistics summarized antibiotics; propensity score adjusted regression models were fit to compare outcomes. ResultsTwo hundred and seventy-six patients with 439 XDRAB cultures and Gram-negative targeted antibiotic treatment were included. One hundred and eighteen (43%) patients received monotherapy while 158 (57%) received combination therapy, most commonly including a carbapenem (n = 106, 67%) and polymyxin (n = 66, 42%). One hundred and eighty-four (67%) patients received inadequate treatment. In adjusted models, combination therapy did not decrease the odds of in-hospital (aOR 1.24, 95%CI 0.60-2.59) or 30-day (aOR 1.43, 95%CI 0.86-2.38) mortality, or median postculture length of stay (aIRR 1.11, 95%CI 0.86-1.43). Likewise, receipt of inadequate treatment was not associated with poorer outcomes. ConclusionsIn this national cohort of patients with XDRAB, neither combination therapy nor receipt of adequate treatment improved outcomes. Further research is needed on optimal management of this difficult-to-treat pathogen with few effective antibiotic options.

Use of post-discharge heparin prophylaxis and the risk of venous thromboembolism and bleeding following bariatric surgery.

Venous thromboembolism (VTE) is a significant cause of morbidity and mortality after bariatric surgery. Roughly 80% of VTEs occur post-discharge. The frequency of post-discharge heparin (PDH) prophylaxis use is unknown, and evidence about benefits and risks is limited. We aimed to determine the rate of use of PDH prophylaxis and evaluate its relationship with VTE and bleeding events. Using the Truven Health MarketScan® database, we performed a retrospective cohort study (2007-2015) of adult patients who underwent sleeve gastrectomy or gastric bypass. We determined PDH prophylaxis from outpatient pharmacy claims, and post-discharge 90-day VTE and bleeding events from outpatient and inpatient claims. We used propensity score-adjusted regression models to mitigate confounding bias. Among 43,493 patients (median age 45years; 78% women; 77% laparoscopic gastric bypass, 17% laparoscopic sleeve gastrectomy, 6% open gastric bypass), 6% received PDH prophylaxis. Overall, 224 patients (0.52%) experienced VTEs, and 806 patients (1.85%) experienced bleeding. The unadjusted VTE rate did not differ between patients who did and did not receive PDH prophylaxis (0.39% vs. 0.52%, respectively; p = 0.347). The unadjusted bleeding rate was higher for the PDH prophylaxis group (2.74% vs. 1.80%, p < 0.001). In our adjusted analysis, a 23% lower risk of VTE in the PDH prophylaxis group was not statistically significant (odds ratio [OR] 0.77, 95% confidence interval [CI] 0.41 to 1.46), whereas the 47% higher risk of bleeding was statistically significant (OR 1.47, 95% CI 1.14 to 1.88). PDH prophylaxis after bariatric surgery is uncommon. In our analysis, use was not associated with a lower VTE risk but was associated with a higher bleeding risk.

Evaluating the Cost-Effectiveness of the ABCDE Bundle: Impact of Bundle Adherence on Inpatient and 1-Year Mortality and Costs of Care.

Growing evidence supports the Awakening and Breathing Coordination, Delirium monitoring/management, and Early exercise/mobility (ABCDE) bundle processes as improving a number of short- and long-term clinical outcomes for patients requiring ICU care. To assess the cost-effectiveness of this intervention, we determined the impact of ABCDE bundle adherence on inpatient and 1-year mortality, quality-adjusted life-years, length of stay, and costs of care. We conducted a 2-year, prospective, cost-effectiveness study in 12 adult ICUs in six hospitals belonging to a large, integrated healthcare delivery system. Hospitals included a large, urban tertiary referral center and five community hospitals. ICUs included medical/surgical, trauma, neurologic, and cardiac care units. The study included 2,953 patients, 18 years old or older, with an ICU stay greater than 24 hours, who were on a ventilator for more than 24 hours and less than 14 days. ABCDE bundle. We used propensity score-adjusted regression models to determine the impact of high bundle adherence on inpatient mortality, discharge status, length of stay, and costs. A Markov model was used to estimate the potential effect of improved bundle adherence on healthcare costs and quality-adjusted life-years in the year following ICU admission. We found that patients with high ABCDE bundle adherence (≥ 60%) had significantly decreased odds of inpatient mortality (odds ratio 0.28) and significantly higher costs ($3,920) of inpatient care. The incremental cost-effectiveness ratio of high bundle adherence was $15,077 (95% CI, $13,675-$16,479) per life saved and $1,057 per life-year saved. High bundle adherence was associated with a 0.12 increase in quality-adjusted life-years, a $4,949 increase in 1-year care costs, and an incremental cost-effectiveness ratio of $42,120 per quality-adjusted life-year. The ABCDE bundle appears to be a cost-effective means to reduce in-hospital and 1-year mortality for patients with an ICU stay.

PD50-08 THE IMPACT OF LOW- VERSUS HIGH-INTENSITY SURVEILLANCE CYSTOSCOPY ON SURGICAL CARE AND CANCER OUTCOMES IN PATIENTS WITH HIGH-RISK NON-MUSCLE-INVASIVE BLADDER CANCER (NMIBC)

INTRODUCTION AND OBJECTIVE: Surveillance guidelines for NMIBC are based on expert opinion and informed by limited evidence. To assess the association of low- vs. guideline-recommended high-intensity cystoscopic surveillance with outcomes among patients with high-risk non-muscle invasive bladder cancer (NMIBC). METHODS: A retrospective cohort study of Veterans Affairs patients diagnosed with high-risk NMIBC between 2005 and 2011 with follow-up through 2014. Patients were categorized by number of surveillance cystoscopies over two years following diagnosis: low- (1-5) vs. high-intensity (6 or more) surveillance. Propensity score adjusted regression models were used to assess the association of low-intensity cystoscopic surveillance with frequency of transurethral resections, and risk of progression to invasive disease and bladder cancer death. RESULTS: Among 1,542 patients, 520 (33.7%) underwent low-intensity cystoscopic surveillance. Patients undergoing low-intensity surveillance had fewer transurethral resections (37 vs. 99 per 100 person-years; p<0.001). Low vs. high-intensity surveillance was not associated with risk of bladder cancer death among patients with non-invasive (cumulative incidence [CIn] 5.7% vs. 8.2% at 5 years, p=0.25) or with invasive disease at diagnosis (CIn 10.1% vs. 9.7% at 5 years, p=0.81). Among a subset of patients with non-invasive disease, low-intensity surveillance was associated with decreased risk of progression to invasive disease or bladder cancer death (CIn 19.3% vs. 31.4% at 5 years, p=0.002). CONCLUSIONS: Patients with high-risk NMIBC undergoing low- vs. high-intensity cystoscopic surveillance underwent fewer transurethral resections, but did not experience an increased risk of progression or bladder cancer death. These findings provide a strong rationale for a clinical trial to determine whether low-intensity surveillance is comparable to high-intensity surveillance for cancer control in high-risk NMIBC.Source of Funding: None

The impact of low- versus high-intensity surveillance cystoscopy on surgical care and cancer outcomes in patients with high-risk non-muscle-invasive bladder cancer (NMIBC).

To assess the association of low- vs. guideline-recommended high-intensity cystoscopic surveillance with outcomes among patients with high-risk non-muscle invasive bladder cancer (NMIBC). A retrospective cohort study of Veterans Affairs patients diagnosed with high-risk NMIBC between 2005 and 2011 with follow-up through 2014. Patients were categorized by number of surveillance cystoscopies over two years following diagnosis: low- (1-5) vs. high-intensity (6 or more) surveillance. Propensity score adjusted regression models were used to assess the association of low-intensity cystoscopic surveillance with frequency of transurethral resections, and risk of progression to invasive disease and bladder cancer death. Among 1,542 patients, 520 (33.7%) underwent low-intensity cystoscopic surveillance. Patients undergoing low-intensity surveillance had fewer transurethral resections (37 vs. 99 per 100 person-years; p<0.001). Risk of death from bladder cancer did not differ significantly by low (cumulative incidence [CIn] 8.4% [95% CI 6.5-10.9) at 5 years) vs. high-intensity surveillance (CIn 9.1% [95% CI 7.4-11.2) at 5 years, p = 0.61). Low vs. high-intensity surveillance was not associated with increased risk of bladder cancer death among patients with Ta (CIn 5.7% vs. 8.2% at 5 years p = 0.24) or T1 disease at diagnosis (CIn 10.2% vs. 9.1% at 5 years, p = 0.58). Among patients with Ta disease, low-intensity surveillance was associated with decreased risk of progression to invasive disease (T1 or T2) or bladder cancer death (CIn 19.3% vs. 31.3% at 5 years, p = 0.002). Patients with high-risk NMIBC undergoing low- vs. high-intensity cystoscopic surveillance underwent fewer transurethral resections, but did not experience an increased risk of progression or bladder cancer death. These findings provide a strong rationale for a clinical trial to determine whether low-intensity surveillance is comparable to high-intensity surveillance for cancer control in high-risk NMIBC.

Abstract WP2: Anesthesia Technique and Outcomes of Mechanical Thrombectomy in Patients With Acute Ischemic Stroke

Background: The impact of anesthesia technique on the outcomes of mechanical thrombectomy for acute ischemic stroke remains an issue of debate, and has not been studied in clinical trials. We investigated the association of general anesthesia with outcomes in patients undergoing mechanical thrombectomy for ischemic stroke. Methods: We performed a cohort study involving patients undergoing mechanical thrombectomy for ischemic stroke from 2009-2013, who were registered in the New York Statewide Planning and Research Cooperative System (SPARCS) database. An instrumental variable (hospital rate of general anesthesia) analysis was used to simulate the effects of randomization and investigate the association of anesthesia technique with case-fatality and length of stay (LOS). Results: Of the 1,308 patients undergoing mechanical thrombectomy for acute ischemic stroke, 492 (37.6%) underwent general anesthesia, and 816 (62.4%) underwent conscious sedation. Employing an instrumental variable analysis, we identified that general anesthesia was associated with a 6.4% increased case-fatality (95% CI, 1.9% to 11.0%), and 8.4 days longer LOS (95% CI, 2.9 to 14.0) in comparison to conscious sedation. This corresponded to 15 patients needing to be treated with conscious sedation to prevent one death. Our results were robust in a sensitivity analysis utilizing mixed effects regression, and propensity score adjusted regression models. Conclusions: Using a comprehensive all-payer cohort of acute ischemic stroke patients undergoing mechanical thrombectomy in New York State, we identified an association of general anesthesia with increased case fatality and LOS. These considerations should be taken into account when standardizing acute stroke care.

Anesthesia Technique and Outcomes of Mechanical Thrombectomy in Patients With Acute Ischemic Stroke

The impact of anesthesia technique on the outcomes of mechanical thrombectomy for acute ischemic stroke remains an issue of debate. We investigated the association of general anesthesia with outcomes in patients undergoing mechanical thrombectomy for ischemic stroke. We performed a cohort study involving patients undergoing mechanical thrombectomy for ischemic stroke from 2009 to 2013, who were registered in the New York Statewide Planning and Research Cooperative System database. An instrumental variable (hospital rate of general anesthesia) analysis was used to simulate the effects of randomization and investigate the association of anesthesia technique with case-fatality and length of stay. Among 1174 patients, 441 (37.6%) underwent general anesthesia and 733 (62.4%) underwent conscious sedation. Using an instrumental variable analysis, we identified that general anesthesia was associated with a 6.4% increased case-fatality (95% confidence interval, 1.9%-11.0%) and 8.4 days longer length of stay (95% confidence interval, 2.9-14.0) in comparison to conscious sedation. This corresponded to 15 patients needing to be treated with conscious sedation to prevent 1 death. Our results were robust in sensitivity analysis with mixed effects regression and propensity score-adjusted regression models. Using a comprehensive all-payer cohort of acute ischemic stroke patients undergoing mechanical thrombectomy in New York State, we identified an association of general anesthesia with increased case-fatality and length of stay. These considerations should be taken into account when standardizing acute stroke care.

Surgical Clipping versus Endovascular Intervention for the Treatment of Subarachnoid Hemorrhage Patients in New York State

ObjectRandomized trials have demonstrated a survival benefit for endovascular treatment of ruptured cerebral aneurysms. We investigated the association of surgical clipping and endovascular coiling with outcomes in subarachnoid hemorrhage (SAH) patients in a real-world regional cohort.MethodsWe performed a cohort study involving patients with ruptured cerebral aneurysms, who underwent surgical clipping, or endovascular coiling from 2009–2013 and were registered in the Statewide Planning and Research Cooperative System (SPARCS) database. An instrumental variable analysis was used to investigate the association of treatment technique with outcomes.ResultsOf the 4,098 patients undergoing treatment, 2,585 (63.1%) underwent coiling, and 1,513 (36.9%) underwent clipping. Using an instrumental variable analysis, we did not identify a difference in inpatient mortality [marginal effect (ME), -0.56; 95% CI, -1.03 to 0.02], length of stay (LOS) (ME, 1.72; 95% CI, -3.39 to 6.84), or the rate of 30-day readmissions (ME, -0.30; 95% CI, -0.82 to 0.22) between the two treatment techniques for patients with SAH. Clipping was associated with a higher rate of discharge to rehabilitation (ME, 0.63; 95% CI, 0.24 to 1.01). In sensitivity analysis, mixed effect regression, and propensity score adjusted regression models demonstrated identical results.ConclusionsUsing a comprehensive all-payer cohort of patients in New York State presenting with aneurysmal SAH we did not identify an association of treatment method with mortality, LOS or 30-day readmission. Clipping was associated with a higher rate of discharge to rehabilitation.

One-year outcomes of inhaled controller therapies added to systemic corticosteroids after asthma-related hospital discharge

Much of the evidence on the early use of inhaled controllers after severe asthma exacerbations is about their short-term benefit, leaving a gap in evidence on their longer-term outcomes. We used administrative health data from British Columbia, Canada (2001-2012) to evaluate readmission rate (primary outcome), adherence to controller medications, and use of reliever medications associated with different inhaled controller treatments as an add-on to systemic corticosteroids (SCS) over one-year following discharge from an asthma-related admission in individuals 12-55 years of age. Exposure was assessed in the 60 days after discharge, and categorized as monotherapy with SCS (SCS-only) versus SCS plus inhaled controller therapy (SCS + inhaler); the latter was further divided into SCS + inhaled corticosteroid (SCS + ICS) and SCS + ICS and long-acting beta agonists (SCS + ICS/LABA). Propensity score-adjusted regression models were used to estimate relative rates (RR) of outcomes across exposure groups. The final cohort included 2,272 post-discharge periods (43.0% SCS-only, 26.9% SCS + ICS, and 30.1% SCS + ICS/LABA). Readmission rate was significantly lower in the SCS + inhaler versus SCS-only (RR = 0.74 [95%CI 0.59-0.93]), but similar between SCS + ICS and SCS + ICS/LABA (RR = 0.78 [95%CI 0.59-1.04]). Long-term adherence, defined as medication possession ratio, to controller medications was 83% higher in SCS + inhaler than SCS-only, and 64% higher in SCS + ICS/LABA than in SCS + ICS. The use of reliever medications was similar across exposure groups. Early initiation of inhaled controllers after discharge from an asthma-related hospitalization was associated with significantly better long-term adherence to controller medications as well as reduced rate of readmissions. Combination therapy with ICS/LABA seems to be at least as effective as mono-therapy with ICS in reducing the risk of readmission, with the added benefit of better long-term adherence.

The association between atherosclerotic renal artery stenosis and acute kidney injury in patients undergoing cardiac surgery.

BackgroundAtherosclerotic renal artery stenosis (ARAS) and coronary artery disease (CAD) commonly co-exist. Some patients with unidentified ARAS may undergo cardiac surgery. While acute kidney injury (AKI) is a frequent and serious complication of cardiac surgery, we aim to evaluate the influence of ARAS on the occurrence of postoperative AKI in patients with normal or near-normal baseline renal function following cardiac surgery.MethodsA total of 212 consecutive patients undergoing aortography after coronary angiography and cardiac surgery were retrospectively studied for their preoperative and intraoperative conditions. AKI was defined as an absolute increase in serum creatinine of more than or equal to 0.3 mg/dl (≥26.4 µmol/l) or a percentage increase in creatinine of more than or equal to 50% (1.5-fold from baseline) after cardiac surgery. A propensity score-adjusted logistic regression models was used in estimating the effect of ARAS on the risk of postoperative AKI.ResultsARAS (≥50%) was observed in 50 (23.6%) patients, and 83 (39.2%) developed AKI after cardiac surgery. A correlation existed between renal artery patency and preoperative–to–postoperative %ΔCr in patients with ARAS (r = 0.297, P<0.0001). The propensity score-adjusted regression model showed the occurrence of postoperative AKI in patients with ARAS was significantly higher than those without ARAS (OR 2.858, 95% CI 1.260–6.480, P = 0.011).ConclusionARAS is associated with postoperative AKI in patients with normal or near-normal baseline renal function after cardiac surgery.

Comparison of multivariable-adjusted logistic regression model with propensity score techniques using pharmacy claims data

Purpose To compare the multivariable-adjusted logistic regression model with the propensity score-matched, propensity score-stratified and propensity score-adjusted logistic regression models in estimating the effect of exposure to antidepressant agents in increasing the risk for type 2 diabetes mellitus. Methods A retrospective cohort study in the USA, using the Texas Medicaid prescription claims database was conducted from 1 January 1 2002 to 31 December 2009. Patients aged 18–64 years with new prescriptions for antidepressants (exposed group) or benzodiazepines (unexposed group) during the study period constituted the base population. Patients without diabetes at cohort entry were included in the study. Propensity scores, which predicted exposure to antidepressant agents, were used to create propensity score-matched, propensity score-stratified and propensity score-adjusted logistic regression models. Results A total of 44 715 patients formed the study sample. The risk estimates varied across different analytic methods. The propensity score-matched logistic regression model yielded the highest risk estimate (relative risk (RR) = 1.931; 95% confidence interval (CI): 1.705 to 2.187). The propensity score-stratified model (RR = 1.457; 95% CI: 1.127 to 1.884), the propensity score-adjusted regression model (RR = 1.491; 95% CI: 1.334 to 1.665) and the multivariable-adjusted logistic regression model (RR = 1.478; 95% CI: 1.323 to 1.653) yielded similar risk estimates. Conclusions Propensity score techniques using pharmacy claims data with a limited number of covariates yielded varied estimates of the treatment effect. The propensity score-matched model yielded a less biased treatment effect estimate than the multivariable-adjusted, the propensity score-stratified, and the propensity score-adjusted regression models.