Journal watch: Recent studies of note

Hospitalists' cost-effectiveness, vasopressin antagonists and hyponatremia, and more.

Hospitalists can be cost-effective for per diem reimbursement hospitals

Implementing a hospitalist team can be cost-effective at hospitals that rely almost solely on per diem reimbursement, and where the inpatient census exceeds teaching service limits, according to a study.

In response to inpatient admissions that had increased beyond the capacity of ward teams, Olive View-UCLA Medical Center in Sylmar, Calif., instituted a daytime admitting hospitalist service in December 2007. The team initially comprised one hospitalist who worked 50 hours per week and one nurse practitioner (NP) who worked 40 hours per week; in July 2008, a resident doctor was added at no cost by combining a hospitalist rotation with an internal medicine rotation.

The authors assessed cost-effectiveness by comparing the average inpatient census, payment denial rate, and the state's Medicaid reimbursement (Medi-Cal) for internal medicine in 2007 and 2008. In 2008, they also focused on Medi-Cal patients admitted with low-risk chest pain, comparing length-of-stay and denied-day rate data with data from 2005. Results were published in the August 2010 Journal of Academic Medicine.

Medi-Cal reimbursement was higher by $2,310,000 in 2008 than 2007, while the total salary outlay for the first year of the service was $310,000, the researchers found. The overall payment denial rate dropped to 27.4% from 29%, while yearly admissions increased from 8,069 to 8,643. The average daily census rose to 107.1 patients from 97.7 patients. For low-risk chest pain admissions, length of stay fell to 1.92 days from 2.48 days; the denial rate fell to 31.8% from 43.8%; and average reimbursement per inpatient day rose to $955 from $787.

Other studies have shown hospitalist-based care in teaching hospitals can be cost-effective, usually based on reducing length of stay and costs in either a per case or a capitated reimbursement model, the researchers noted. This study shows that a hospitalist service focusing on short-stay patients in a public teaching hospital, which relies mostly on per diem, retrospective-review-based payment, can be cost-effective, as well.

The main limitation of this study's applicability, however, is that the drivers of the higher revenue came from increases in patient throughput and in the total census afforded by the hospitalists, in the context of unmet inpatient demand related to IM Residency Review Committee regulations.

“Hospitals that are not already at maximum IM service capacity or that have fewer short-stay admissions may not derive as much benefit as we did,” the authors qualified. Still, the advantages of implementing the service went beyond the financial, they said, as the hospitalists helped enhance patient flow, provided backup for bedside procedures, screened transfer requests, participated in patient safety and improved patient satisfaction.

Vasopressin antagonists helpful in hyponatremia

Vasopressin antagonists are an effective treatment for both hypervolemic and euvolemic hyponatremia, according to a study.

Researchers performed a meta-analysis of 15 trials, all industry-sponsored, to determine the safety and efficacy of vasopressin antagonists, with or without fluid restriction, in patients with hyponatremia. The primary outcome measure was response rate, defined as normalization of or significant increase in serum sodium (≥5 to 6 mEq/L), at three to seven days. Secondary outcomes included late response rate (after seven days), change in serum sodium level from baseline, adverse events, and rates of rapid serum sodium level correction and hypernatremia. The vasopressor antagonists studied included tolvaptan, satavaptan, conivaptan and lixivaptan. Eleven trials involving 1,125 patients assessed early response rate, and four trials involving 549 patients assessed late response rate. Study results appeared in the August 2010 American Journal of Kidney Diseases.

Vasopressin antagonists significantly increased both early (relative risk [RR], 3.15; 95% CI, 2.27 to 4.37) and late (RR, 2.27; 95% CI, 1.79 to 2.89) response rates. These effects were seen in both euvolemic and hypervolemic patients but appeared to be greater in the former group. Early and late change from baseline in serum sodium level also increased significantly with treatment (weighted mean difference, 5.27 mEq/L; 95% CI, 4.27 to 6.26 mEq/L and 3.49 mEq/L; 95% CI, 2.56 to 4.41 mEq/L).

Treatment with vasopressin antagonists increased risk of rapid sodium level correction but did not affect rates of hypernatremia or adverse events. There was also no report of osmostic demyelination syndrome. Mortality rates were similar in patients who received vasopressin antagonists and those who did not (RR, 0.79; 95% CI, 0.44 to 1.42).

The authors noted that the included trials involved only short-term effects, offered no information on clinical outcomes and did not look at sicker patients. However, they concluded that vasopressin receptor antagonists are safe and effective for euvolemic and hypervolemic patients with hyponatremia. They recommended that serum sodium levels be frequently monitored in patients receiving these drugs, and called for further studies to examine their efficacy over the long-term and in severe cases, as well as their impact on clinical outcomes. The role of fluid restriction in patients taking vasopressin receptor antagonists should also be clarified, they said.

Two models superior at predicting long ICU stay after cardiac surgery

The Parsonnet and EuroSCORE prediction models are superior at identifying patients likely to have a prolonged ICU length of stay after cardiac surgery, a study found.

Researchers identified 20 ICU length-of-stay prediction models via literature review, of which 14 were included in the study. Validation of the models was then performed on patients who underwent cardiac surgery between January 2000 and July 2008, comprising 11,395 surgical interventions.

The probabilities of prolonged ICU length of stay (PICULOS) based on the models were compared with the actual outcome, in order to determine the discrimination and calibration of the models. Discrimination meant the extent to which the model distinguished between patients with and without PICULOS, while calibration was the extent to which the predicted probability of PICULOS reflected the true probability of prolonged ICU stay. PICULOS was considered longer than 48 hours. Results were published in the Aug. 17, 2010 Circulation.

Of six models meant for the general cardiac surgery population, the Parsonnet model showed the best discrimination (area under the receiver-operating characteristic curve [AUC], 0.75; 95% CI, 0.73 to 0.76), followed by the European system for cardiac operative risk evaluation, or EuroSCORE (AUC, 0.71; 95% CI, 0.70 to 0.72) and the Amphiascore (AUC, 0.71; 95% CI, 0.70 to 0.73). Most models demonstrated good calibration.

The results also indicated it is more complicated to predict PICULOS in isolated coronary artery bypass graft patients than in the cardiac surgery population as a whole; the Parsonnet and EuroSCORE models had the best discrimination (0.69 and 0.68) in this population. All told, the Parsonnet and EuroSCORE models showed the best performance in terms of discrimination, accuracy and calibration.

Though the Parsonnet and EuroSCORE models were originally developed to predict mortality after surgery, they have been used and validated for PICULOS. It's possible they perform well in this role because morbidity has increased and mortality has decreased since the models were developed, the authors noted.

“Because of advances in perioperative care in cardiac surgery, most of the patients who were likely to die in the era when [the models] were developed will now survive, but they still have a higher probability of developing complications,” they wrote. Indeed, both models overestimate mortality in practice, they said.

The Parsonnet and EuroSCORE models are already widely used in daily practice to predict mortality risk, which makes it easy to use them for identifying probable patients for a prolonged ICU stay. “This knowledge, when available before surgery, can be used for timely planning of postoperative care and ICU management,” the researchers concluded.

Simplified index predicts 30-day mortality in PE patients as well as original

A simplified version of the Pulmonary Embolism Severity Index (PESI) predicted 30-day mortality rates for acute pulmonary embolism (PE) patients as accurately as the original index, a study found.

Researchers retrospectively developed a simplified clinical prediction rule based on the PESI, which estimates 30-day mortality risk in patients with acute PE. In a derivation cohort, they compared the prognostic accuracy of the original and simplified PESI in patients at a Spanish hospital who were diagnosed with acute PE. They also performed external validation of the simplified version in a multinational cohort of 7,106 outpatients with acute symptomatic PE, using data from the Registro Informatizado de la Enfermedad Tromboembólica (RIETE). Results were published in the Aug. 9/23, 2010 Archives of Internal Medicine.

On univariate analysis of 995 evaluable patients, the researchers found that the variables of sex, respiratory rate, temperature and altered mental status weren't significantly associated with 30-day mortality, and thus they weren't included in the simplified PESI. Included were the variables of age, history of cancer, history of chronic cardiopulmonary disease, heart rate (≥110 beats/min vs. other), systolic blood pressure (<100 mg Hg vs. other), and oxyhemoglobin saturation level (<90% vs. other). The prognostic accuracy of the original and simplified PESI did not differ (area under the curve, 0.75; 95% CI, 0.69 to 0.80). Thirty-one percent of those who were classified as low risk by the simplified PESI had a 30-day mortality rate of 1.0% (95% CI, 0.0% to 2.1%) versus 10.9% (95% CI, 8.5% to 13.2%) in the high-risk group. In the validation cohort, 36.2% of patients were classified as having a low risk of death; the mortality risk of this group was 1.1% (95% CI, 0.7% to 1.5%) versus 8.9% (8.1% to 9.8%) with the high-risk group.

While the original PESI uses 11 variables with different weights, and its scoring relies on calculations that could be difficult to apply in a clinical setting, the simplified version uses just six variables, the authors noted. The simplified version is also useful, they said, because it includes one domain that quantifies age, two that capture coexisting illness, and three that express the cardiopulmonary consequences of PE. The simplified PESI is also likely to be accurate for identifying low-risk patients in the real world, since the data came from management registries and not clinical trials, they said.

Age, disability among indicators of medication adherence 3 months after stroke

Increasing age, lower stroke-related disability, and several other factors make it more likely a patient will continue adhering to discharge medications three months after a stroke, a study found.

The AVAIL (Adherence Evaluation After Ischemic Stroke–Longitudinal) investigators analyzed data from hospitals participating in the Get with the Guidelines–Stroke program to determine what variables were associated with long-term medication adherence after hospital discharge for stroke. The main outcome measures were regimen persistence from discharge to three months for five classes of medications (antiplatelet therapies, warfarin, antihypertensive therapies, lipid-lowering therapies or diabetes medications) and reasons for nonpersistence. The study results were published online Aug. 9 by Archives of Neurology and appeared in the December 2010 print issue.

Overall, 2,598 patients at 106 U.S. hospitals were included in the study analysis. Of these, 75.5% continued to take all of the stroke prevention medications prescribed at discharge three months later. Patients were most likely to continue taking antihypertensive and antiplatelet medications. Patients who were older, had less severe stroke-related disability, had been prescribed fewer discharge medications, and had insurance were more likely to continue taking their medications. Patients who understood why they were taking the medications and how to get them refilled were also more likely to take them long-term. Better quality of life, greater financial hardship, working status, geographic region and hospital size were also associated with adherence at three months.

The authors noted that although about three-quarters of patients did continue taking their stroke prevention medications three months after discharge, about a quarter did not. They also pointed out that rates might not be generalizable at hospitals not participating in Get with the Guidelines, which might not be as focused on stroke care.

Although their study had other limitations, including use of self-reported data and lack of information on clinician visits at three months, they concluded that long-term adherence to stroke medications depends on many factors, some modifiable. Using their data, they wrote, “We can begin to develop and evaluate strategies to improve appropriate use of evidence-based therapies and reduce the risk of recurrent stroke.”

Confusion Assessment Method ranks highest for diagnosing inpatient delirium

The Confusion Assessment Method (CAM) is the best of 11 bedside instruments for assessing delirium, a review found.

Researchers used MEDLINE and EMBASE to find 25 prospective studies (n=3,027 patients) of diagnostic accuracy that compared at least one bedside instrument for delirium to a diagnosis made by a geriatrician, neurologist or psychiatrist that was based on the Diagnostic and Statistical Manual of Mental Disorders (DSM-III, DSM-III-R or DSM-IV). Studies with hospitalized patients in the ICU were excluded, as were studies involving mostly alcohol-related delirium and those in which the index and reference tests were performed by the same person. Studies had to involve a bedside instrument that didn't require special equipment and could be administered by a non-expert. Results were published in the Aug. 18, 2010 Journal of the American Medical Association.

The 11 bedside instruments included in the analysis were Clinical Assessment of Confusion (CAC), CAM, Delirium Observation Screening Scale (DOSS), Delirium Rating Scale (DRS), Delirium Rating Scale-Revised-98 (DRS-R-98), Digit Span Test, Global Attentiveness Rating (GAR), Memorial Delirium Assessment Scale (MDAS), Mini-Mental State Examination (MMSE), Nursing Delirium Screening Scale (Nu-DESC) and Vigilance “A” Test.

Of these instrments, the following had positive results that suggested delirium with likelihood ratios (LRs) greater than 5.0: GAR, MDAS, CAM, DRS-R-98, CAC and DOSS. Normal results that decreased the likelihood of delirium with LRs less than 0.2 were calculated for the GAR, MDAS, CAM, DRS-R-98, DRS, DOSS, Nu-DESC and MMSE. The Digit Span and Vigilance “A” tests had limited utility in isolation.

When the authors considered ease of use, test performance and clinical importance of the heterogeneity in confidence intervals of the LRs, the CAM was the best bedside instrument (summary positive LR, 9.6; 95% CI, 5.8 to 16.0; summary-negative LR, 0.16; 95% CI, 0.09 to 0.29). The commonly used MMSE was the least useful for identifying patients with delirium (LR, 1.6; 95% CI, 1.2 to 2.0). The CAM does take five minutes to administer, which may be too much time for busy physicians, the authors noted. The two-minute general conversation that defines the GAR could be a good alternative, but its generalizability may be limited to those with expertise in this patient population, they said.

Most ICU patients die within 24 hours of terminal withdrawal of mechanical ventilation

Most ICU patients die within 24 hours of terminal withdrawal of mechanical ventilation, and about half die within one hour, according to a study.

Researchers performed a secondary analysis of data from a cluster randomized trial meant to improve end-of-life care for ICU patients at 14 Washington hospitals. They studied 1,505 adult patients who died in the ICU, or within 30 hours of discharge from the ICU, following terminal withdrawal of mechanical ventilation between August 2003 and February 2008. Patients' charts and death certificates were used to abstract time of death and predictors such as demographics, proxies of illness severity, life-sustaining therapies and ICD-9 codes. Results were published in the August 2010 Chest.

Time to death after mechanical ventilation was withdrawn varied widely; the range was 0 to 6.9 days. The median (interquartile range) time to death was 0.93 hours (0.25 to 5.5 hours); 93.2% (95% CI, 92% to 94%) of patients died within 24 hours. About 9% of patients were discharged from the ICU before death; the median time to death from discharge for this group was 8.8 hours, with a range of 17 minutes to 28.8 hours.

While age was a strong predictor of time to death, older patients had significantly longer times to death than their younger counterparts. Women had longer median times to death than men (1.17 hours for women vs. 0.75 hour for men; P=0.003). As individual comorbidities, chronic respiratory disease, nonmetastatic cancer and dementia were associated with longer time to death.

Nonwhite patients also had shorter time to death than white patients (hazard ratio [HR], 1.17; 95% CI, 1.01 to 1.35), as did those who had a greater number of organ failures (per organ HR, 1.11; 95% CI, 1.04 to 1.19), were on the surgical (vs. medical) service (HR, 1.29; 95% CI, 1.06 to 1.56), used vasopressors before withdrawal (HR, 1.67; 95% CI, 1.49 to 1.88), and used IV fluids before withdrawal (HR, 1.16; 95% CI, 1.01 to 1.32).

Differences in illness severity across age groups at the time of withdrawal would suggest that a combination of age and acute severity of illness were factored into the decision to withdraw mechanical ventilation, the authors noted.

“Providers may be more willing to withdraw mechanical ventilation earlier in older patients who have poor long-term prognosis with less attention to their short-term severity of illness; on the other hand, uncertainty in the long- term prognosis for younger patients may delay withdrawal until outcome of death is more immediate and certain,” they wrote.

As for the results by gender, women have been shown to prefer less invasive measures than men and thus may be more likely to withdraw ventilatory support earlier in the course of illness, but a cited study raised the possibility of gender bias. The difference by race may, in part, be a result of differences in unmeasured severity of illness, the authors added; black patients often have greater illness severity at time of admission to the ICU.

While the results require further validation, they may help clinicians with counseling families at the end of a patient's life. “Characterization of the factors that predict time to death may inform family-caregiver communication at the end of life and alleviate some of the anxiety and frustration resulting from excessive uncertainty regarding the anticipated time course to death,” they wrote, referring to a 2006 article by Wiegand in the American Journal of Critical Care.

Reminders to remove urinary catheters help reduce infection risk

Systems that remind clinicians to remove urinary catheters from hospitalized patients help reduce urinary tract infections (UTIs), according to a study.

Researchers performed a meta-analysis of 14 interventional studies in hospitalized patients that evaluated use of either reminders to nurses and physicians about existing catheters, or “stop orders” prompting clinicians to remove catheters. One study was a randomized, controlled trial; the rest were quasi-experimental preintervention-postintervention trials. Reminders only reminded clinicians that a catheter was in place and should be removed if it was no longer needed; stop orders prompted clinicians to remove clinically inappropriate catheters by default after a certain amount of time had passed or certain clinical conditions had been met. Primary outcomes were development of catheter-associated UTI, use of urinary catheters and recatheterization rates. The study appeared in the Sept. 1, 2010 Clinical Infectious Diseases.

In the included studies, reminder systems and stop orders decreased rates of catheter-associated UTIs by 52% (P<0.001) and duration of catheterization by 37%. Overall, there were 2.61 fewer days of catheterization in the intervention groups compared with the control groups, with an overall pooled standardized mean difference of -1.11 (P=0.070) in duration of catheterization. Recatheterization rates were similar between the intervention and control groups in the four studies that reported this outcome.

The authors acknowledged significant heterogeneity and a lack of randomized, controlled trials among the included studies. However, they concluded that reminder systems and stop orders for removal of urinary catheters help to decrease UTIs in hospitalized patients without much cost. Such mechanisms should be used more widely in U.S. hospitals, they said.