James E. Goin

Development and Prospective Validation of a Clinical Index to Predict Survival in Ambulatory Patients Referred for Cardiac Transplant Evaluation

BACKGROUND Risk stratification of patients with end-stage congestive heart failure is a critical component of the transplant candidate selection process. Accurate identification of individuals most likely to survive without a transplant would facilitate more efficient use of scarce donor organs. METHODS AND RESULTS Multivariable proportional hazards survival models were developed with the use of data on 80 clinical characteristics from 268 ambulatory patients with advanced heart failure (derivation sample). Invasive and noninvasive models (with and without catheterization-derived data) were constructed. A prognostic score was determined for each patient from each model. Stratum-specific likelihood ratios were used to develop three prognostic-score risk groups. The models were prospectively validated on 199 similar patients (validation sample) by calculation of the area under the receiver operating characteristic curve for 1-year event-free survival, the censored c-index for event-free survival, and comparison of event-free survival curves for prognostic-score risk strata. Outcome events were defined as urgent transplant or death without transplant. The noninvasive model performed well in both samples, and increased performance was not attained by the addition of catheterization-derived variables. Prognostic-score risk groups derived from the noninvasive model in the derivation sample effectively stratified the risk of an outcome event in both samples (1-year event-free survival for derivation and validation samples, respectively: low risk, 93% and 88%; medium risk, 72% and 60%; high risk, 43% and 35%). CONCLUSIONS Selection of candidates for cardiac transplantation may be improved by use of this noninvasive risk-stratification model.

A CASE-MIX CLASSIFICATION SYSTEM FOR MEDICAL REHABILITATION

Dissatisfaction with Medicares current system of paying for rehabilitation care has led to proposals for a rehabilitation prospective payment system, but first a classification system for rehabilitation patients must be created. Data for 36,980 patients admitted to and discharged from 125 rehabilitation facilities between January 1, 1990, and April 19, 1991, were provided by the Uniform Data System for Medical Rehabilitation. Classification rules were formed using clinical judgment and a recursive partitioning algorithm. The Functional Independence Measure version of the Function Related Groups (FIM-FRGs) uses four predictor variables: diagnosis leading to disability, admission scores for motor and cognitive functional status subscales as measured by the Functional Independence Measure, and patient age. The system contains 53 FRGs and explains 31.3% of the variance in the natural logarithm length of stay for patients in a validation sample. The FIM-FRG classification system is conceptually simple and stable when tested on a validation sample. The classification system contains a manageable number of groups, and may represent a solution to the problem of classifying medical rehabilitation patients for payment, facility planning, and research on the outcomes, quality, and cost of rehabilitation.

Frequency of magnetic resonance imaging abnormalities in patients with migraine

Background.‐The frequency of magnetic resonance imaging (MRI) abnormalities in patients with migraine has been reported at 12% to 46%. We examined a series of patients to determine the frequency of MRI abnormalities, and any relationship of frequency with patient age, sex, migraine type, duration of symptoms, and other medical conditions.

Functional gain and length of stay for major rehabilitation impairment categories. Patterns revealed by function related groups.

This study evaluates the relationship of functional severity to patterns of functional gain and length of stay (LOS) for patients discharged from medical rehabilitation. It further compares differences in patterns between summed and Rasch transformed subscales of the Functional Independence Measure (FIM). Two different schemes of the FIM-Function Related Groups (FIM-FRGs) are used to define groups of patients who present with similar degrees of functional severity. The first scheme was developed using summed admission motor and cognitive FIM subscores (FIM-FRGs). The second scheme was developed by transforming these same motor and cognitive FIM subscores into logits (Logit FIM-FRGs), thus making FIM scores more equal-interval. The study included 32,494 patients who were discharged from 123 facilities that submitted data to the Uniform Data System for Medical Rehabilitation (UDSMR) and involved the separate evaluation of 18 different rehabilitation impairment categories. Motor FIM gain was calculated for each FRG in both schemes as the patients discharge motor FIM score minus the admission motor FIM score. There were four patterns of motor FIM gain and two patterns of LOS across rehabilitation impairment. The most common pattern in both schemes was linear trend, for which median gains and LOS were highest for patients in the most disabled FRGs and lowest for patients in the least disabled FRGs. Gain patterns differed across impairment and across the two schemes. The motor FIM gain distributions provide clinicians with a range of typical functional outcomes for patients admitted to medical rehabilitation. This descriptive approach provides clinicians and administrators with a simple way to compare the motor FIM gain and LOS patterns of patients teated in local facilities with broad-based norms. This sample includes about one-quarter of rehabilitation facilities nationwide, thus representing population standards for facilities participating in the UDSMR. Suggestions are made on how to use these norms most appropriately for both facility and patient comparison.

Discharge motor fim-function related groups

OBJECTIVE To develop a patient classification system that groups patients achieving similar functional outcome scores by discharge from medical rehabilitation. DESIGN Patient groups were developed using a recursive partitioning algorithm and clinical input. Results were validated in a separate set of patient records. SETTING Two hundred fifty-two free-standing rehabilitation hospitals and distinct part units that participate in the Uniform Data System for Medical Rehabilitation. PATIENTS The 84,492 rehabilitation inpatients discharged in 1992 were grouped into 20 impairment categories. MAIN OUTCOME MEASURE Discharge score on the motor subscale of the Functional Independence Measure (FIM). RESULTS In the Discharge Motor FIM-Function Related Groups (DMF-FRGs) system, patients are first classified into one of 20 impairment categories and then into FRGs by their admission motor FIM scores. Some FRGs are also subdivided on the basis of admission cognitive FIM scores and age. The entire system consists of 139 patient groups that explain 63% of the variation in motor FIM discharge scores in the validation data set. Nontraumatic brain injury and joint replacement DMF-FRGs are provided as examples. CONCLUSION Clinicians can use the DMF-FRGs to identify groups of patients whose motor FIM scores at discharge are below, within, or above nationally established ranges of values for the purpose of outcomes management, guideline development, and quality improvement. The DMF-FRGs can also be considered in the design of an outcome-based payment system for medical rehabilitation.

Efficiency Pattern Analysis for Medical Rehabilitation

Efficiency pattern analysis (EPA) is a technique pro posed for use in medical rehabilitation that links patient functional gain to resource use, as approximated by length of stay (LOS), after adjusting for initial severity. The Functional Independence Measure version of the Function Related Groups (FIM-FRGs) is used to adjust for patient severity and to define the efficiency groups. The efficiency groups are based on LOS and functional gain cut point values in the statistical distribution that are above, below, or within the national interquartile range for each of 53 FRGs. Data from 32,494 patients discharged in 1990 from 123 rehabilitation facilities were used. EPA is a simple way to monitor change in functional gain in response to transformations in health care practices and resource availability. The technique could also provide individual facilities with a means to evaluate treatment efficiencies across time and to com pare patterns of LOS and functional gain to national norms.

Histological predictors of active Helicobacter pylori infection

Helicobacter pylori is a common cause of gastritis. No single test is 100% accurate forH. pylori diagnosis. In order to determine whether the presence of typical histological features ofH. pylori gastritis may yield diagnostic information, we compared antral histology by H&E stain to the presence of organisms as detected on Thiazine stain of antral specimens, CLOtest, urea breath test and anti-H. pylori serology in 50 consecutive patients. Patients were diagnosed as having activeH. pylori infection if at least two of these tests were positive. Patients with only one test positive (N=5) were considered indeterminate forH. pylori and were excluded, resulting in 19 patients (42%) being classified asH. pylori positive. All slides were reviewed by a single blinded expert gastrointestinal pathologist and graded 0 (none) to 3 (severe) for the presence of acute (polymorphonuclear cells) or chronic (lymphocytes, monocytes, plasma cells) inflammation, lymphoid aggregates, and intestinal metaplasia. Active infection was associated with the presence of both acute and chronic inflammation (P<0.0001) but not lymphoid aggregates (P=0.09) or intestinal metaplasia (P=0.10). The best positive predictors of infection were the presence of any acute inflammation (PPV=86%) and the combination of any acute and chronic inflammation (PPV=92%). The best negative predictor was absence of chronic inflammation (NPV=100%). The presence of moderate to severe (grade 2 or 3) acute or chronic inflammation were each 100% predictive of infection. Moderate to severe chronic inflammation had both 100% sensitivity and specificity for activeH. pylori infection, while moderate to severe acute inflammation was only 26% sensitive but 100% specific. The presence of any acute, or the combination of acute and chronic gastritis, is predictive of activeH. pylori infection. Moreover, the predictive value correlates closely with the severity of the inflammation. The absence of chronic inflammatory cells rules out activeH. pylori infection. These findings support the use of H&E histology-determined features in conjunction with other tests to diagnoseH. pylori infection.

CLASSIFYING REHABILITATION INPATIENTS BY EXPECTED FUNCTIONAL GAIN

OBJECTIVES To create a more suitable payment system for medical rehabilitation, the authors developed a companion classification system to the original functional independence measure-function-related groups (FIM-FRGs), which classify patients having similar lengths of stay in a rehabilitation hospital or inpatient unit. The companion system presented here groups patients according to their gains in functional status during the rehabilitation stay. METHODS Data from 84,492 patients discharged from 252 rehabilitation facilities in 1992 were provided by the Uniform Data System for Medical Rehabilitation. Classification rules were formed using clinical judgment and a recursive partitioning algorithm. The gain-FRGs system used four predictor variables: (1) diagnosis leading to disability, admission scores on the (2) motor and (3) cognitive subscales of the FIM, and (4) patient age. RESULTS The gain-FRGs system contained 74 patient groups and explained 21% of the variation in functional gain for patients in a different set of records withheld for validation. CONCLUSIONS The gain-FRGs system should be considered for prospective payment systems because it gives the provider an incentive to improve patient outcomes, which is missing in a payment system based on FIM-FRGs alone.

A comparison of low- with high-osmolality contrast agents in cardiac angiography. Identification of criteria for selective use.

BACKGROUND Controversy exists as to whether low-osmolality radiographic contrast agents, which have less detrimental pharmacological effects but are considerably more expensive than high-osmolality agents, should be used universally or only for selected high-risk patients. METHODS AND RESULTS A randomized, double-blind study was used to compare the frequency and severity of adverse events in 2245 consecutive patients undergoing diagnostic cardiac angiography. Two thousand one hundred sixty-six patients were successfully randomized to either iohexol, a low-osmolality contrast agent, or diatrizoate (as Hypaque 76), a high-osmolality agent. The end point event included clinically important adverse events (which jeopardized the patient or required aggressive treatment), contrast agent-related procedure abbreviations, and conversion to open-label contrast agent. Clinically important end point events were associated with increased age, New York Heart Association functional class, left ventricular end-diastolic pressure, arteriovenous oxygen difference, severity of coronary artery disease, and history of a previous reaction to contrast agent. End point events were less frequent in patients receiving iohexol (2.6% versus 4.6%; adjusted odds ratio, 1.59; 95% confidence interval, 0.97-2.60; P = .07). The difference in event frequency between iohexol and diatrizoate was confined to the highest-risk quartile of the patient population. An algorithm was developed to classify patients as being at high or low risk for an event based on patient age, New York Heart Association class, history of a prior contrast reaction, and left ventricular end-diastolic pressure. Application of this algorithm for selective use of low-osmolality agents only for high-risk patients to a theoretical population of 1000 patients reduced contrast agent costs 66% without increasing the frequency of contrast agent-related adverse events. CONCLUSIONS The advantages of low-osmolality contrast agents are clinically important in patients with severe heart disease but are not in less ill patients. Universal use of low-osmolality agents for cardiac angiography in an unselected population is not necessary. Appropriately guided selective use of low-osmolality contrast agents is feasible and has the potential to reduce cost substantially without compromising safety or effectiveness.