Surgically defined prognostic parameters in patients with early cervical carcinoma. A multivariate survival tree analysis

BACKGROUND

This study was performed to identify a statistical combination of independent pathologic and clinical features that best predict 5-year disease free survival (DFS) in patients with early stage cervical carcinoma treated by radical hysterectomy. The main goal of the study was to identify subsets of patients based on risk factors with maximal differences in DFS.

METHODS

Three hundred and seventy patients were found for whom complete clinical and pathologic material, including cone and cervical biopsies, were available for analysis. Variables studied included age, weight, race, marital status, economic status, tumor size (TS), depth of invasion (DI), lymph-vascular space involvement (LVSI), cell type, tumor grade, lymph node metastasis (LNM), and number of lymph nodes removed. Patients with LNM, parametrial involvement, and positive or close surgical margins were offered postoperative radiation. After excluding patients with microinvasive and small cell carcinoma, data from the remaining 301 patients were submitted to univariate and multivariate analyses to define those variables that best predict DFS.

RESULTS

Univariate analysis showed that, ranked by degree of significance, DI, TS, LVSI, LNM, tumor volume (TV) and clinical stage were significant in predicting survival. Significant (P < 0.05) single parameters and other variables considered important were chosen for multivariate analysis, including the creation of a survival tree. With this method, DI (< or = 6 mm and > 2 cm), LVSI, age (> or = 40 yrs), and LNM were found to be the best combination of risk factors to define prognosis.

CONCLUSIONS

The multivariate survival tree analysis maximally separates patients with early stage invasive carcinoma of the cervix into 3 subgroups with 5-year DFS of 91%, 68%, and 43%, respectively. The authors excluded patients with microinvasive carcinoma (SGO, Society of Gynecologic Oncologists), who have an excellent DFS of 100%, and patients with small carcinoma, who have a poor DFS of 36.4% based on cell type alone, to define independent risk factors that maximally separate the remaining patients by DSF. The survival tree prognostic scoring system is easy to apply, and only requires DI (mm), LVSI (+, -), LNM, and age to assign an individual patient to one of three risk groups.

Geriatric targeting criteria as predictors of survival and health care utilization

OBJECTIVE

To assess the utility of geriatric targeting criteria in predicting survival and health care utilization in a cohort of hospitalized older veterans.

DESIGN

A prospective cohort study assessing geriatric targeting criteria, e.g., polypharmacy, falls, or confusion, with respect to adverse outcomes at 12 months.

SETTING

A Tertiary Care VA Medical Center.

PATIENTS

507 acutely hospitalized male veterans aged 65 years or more.

MAIN OUTCOME MEASURES

Survival status, nursing home placement, and total hospital days during 12 months following hospital admission.

RESULTS

Patients who had a higher number of targeting criteria at admission showed a significantly increasing trend toward death (P < or = .001), nursing home placement (P < or = .01), and longer hospital stays (P < or = .01) at 12 months. In univariate analyses, weight loss (relative hazard 3.8, 95% CI 2.4, 5.9), appetite loss (relative hazard 3.3, 95% CI 1.9, 5.8), depression (relative hazard 2.5, 95% CI 1.4, 4.5), falls (relative hazard 2.2, 95% CI 1.2, 4.1), confusion (relative hazard 2.2, 95% CI 1.2, 4.0), and socioeconomic problems (relative hazard 1.6, 95% CI 1.0, 2.5) predicted death. Polypharmacy (OR 3.4, 95% CI 1.3, 8.8), confusion (OR 4.4, 95% CI 1.5, 13.0), and prolonged bedrest (OR 7.6, 95% CI 1.5, 39.3) predicted nursing home placement. Confusion (Beta 12.0, 95% CI 2.9, 21.3), falls (Beta 14.2, 95% CI 4.2, 24.3), and prolonged bedrest (Beta 22.4, 95% CI 3.9, 41.0) predicted total hospital days. In multivariate analyses, weight loss, depression, and socioeconomic problems predicted death; confusion and polypharmacy predicted nursing home placements; and falls predicted total hospital days.

CONCLUSION

This prospective cohort study of hospitalized older veterans demonstrated geriatric targeting criteria as predictors of adverse hospital outcomes. Our findings suggest screening acutely hospitalized patients using chart abstracted geriatric targeting criteria is useful in identifying patients at risk for adverse outcomes of hospitalization.

Eliminating language barriers for non-English-speaking patients

OBJECTIVES

More than 31 million persons living in the United States do not speak English, therefore language discordance between the clinician and patient may hinder delivery of cost-effective medical care. A new language service was developed in which interpreters are trained in the skills of simultaneous interpretation commonly used at international conferences. The interpreters are linked from a remote site to headsets worn by the clinician and patient through standard communication wires. The service is called "remote-simultaneous interpretation," to contrast it with a traditional method of an interpreter being physically present at the interview and interpreting consecutively "proximate-consecutive interpretation." The aim of this study is to assess in a randomized protocol the quality of communication, interpretation, and level of patient, interpreter, and physician satisfaction with these two language services.

METHODS

The first postpartum visit with each of 49 mothers and their new born babies was assigned randomly to proximate-consecutive interpretation (control) or to remote-simultaneous interpretation (experimental). Main outcome measures included (1) the number of physician and mother utterances in the visit, (2) the quality of the interpretation, and (3) physician, interpreter, and mother preferences between the two services.

RESULTS

The remote-simultaneous interpreter service averaged 8.3 (10%) more physician utterances (95% confidence interval [CI] 4.3, 12.4) and 9.1 (28%) more mother utterances (95% CI 6.1, 12.1). On average, there were 2.8 (12%) fewer inaccuracies of physician utterances in experimental visits compared with control visits (95% CI -5.9, 0.4) and 3.0 (13%) fewer inaccuracies of mother utterances in experimental visits compared with control visits (95% CI -5.4, -0.6). Mothers and physicians significantly preferred the remote-simultaneous service to proximate-consecutive interpretation service. Interpreters stated that they thought mothers and physicians better understood each other using the remote-simultaneous service, although the interpreters preferred to work with the proximate-consecutive service.

CONCLUSIONS

Using remote-simultaneous interpretation to improve the quality of communication in discordant-language encounters promises to enhance delivery of medical care for the millions of non-English-speaking patients in the United States.

Long-term survival of patients with Wegener's granulomatosis from the American College of Rheumatology Wegener's Granulomatosis Classification Criteria Cohort

OBJECTIVE

To determine survivorship in Wegener's granulomatosis (WG) in a well-defined multicenter cohort.

METHODS

Follow-up was obtained for 77 of the 85 patients enrolled in the 1990 American College of Rheumatology vasculitis classification study.

RESULTS

There were 28 deaths (10 females and 18 males) among the 77 patients available for follow-up. Standardized mortality ratios (SMR) were calculated with mortality data from the general population and from this group of patients with WG (an SMR of 1 indicates that expected and observed survival are identical). Overall survivorship among patients with WG was substantially reduced in this cohort (SMR = 4.685 +/- 0.65; for females SMR = 6.814 +/- 1.571; for males SMR = 3.998 +/- 0.69).

CONCLUSION

The life expectancy of patients with WG is reduced compared with the general population.

An index for assessing blindness in a multi-centre clinical trial: disulfiram for alcohol cessation--a VA cooperative study

This paper considers an index to assess the success of blinding with application to a clinical trial of disulfiram. The index increases as the success of blinding increases, accounts for uncertain responses, and is scaled to an interval of 0.0 to 1.0, 0.0 being complete lack of blinding and 1.0 being complete blinding.

Why health care costs more in the US: comparing health care expenditures between systemic lupus erythematosus patients in Stanford and Montreal

OBJECTIVE

Recent studies to identify the causes of higher health care expenditure in the US versus Canada have relied on population-based measures of health care utilization and have restricted their analysis to one sector, such as physician or hospital expenditures. We present a detailed comparative analysis of the direct costs (health services utilized) of treating systemic lupus erythematosus (SLE) patients in Stanford, CA and Montreal, Quebec.

METHODS

Using the self-report Stanford Health Assessment Questionnaire, we assessed 6-month direct costs incurred by 174 American and 164 Canadian SLE patients. We explored 3 potential reasons for the differential expenditure. These were 1) higher prices for health care inputs, 2) more severe disease in the patient case mix, and 3) greater resource utilization.

RESULTS

The direct health care costs for the American SLE patients exceeded those for the Canadian patients by almost 2-fold ($10,530 versus $5,271, expressed in 1991 US dollars). The higher direct costs were explained by the higher price of health services in the US and the more severe disease mix. In fact, for all health resources categories studies, Canadians utilized at least as many services as their American counterparts. Canadians had longer hospital stays, made more emergency room visits, and used more medications.

CONCLUSION

Despite significantly greater per capita health care expenditure in the US, our data show that Canadian SLE patients actually receive more medical services.

Children's memories in the wake of Challenger

OBJECTIVE

The Challenger spacecraft explosion of Jan. 28, 1986, offered an opportunity to study the memories of normal latency and adolescent children of different emotional involvements following one sudden and distant disaster. How would children of various levels of concern express their memories? And if studied over time, how would these narratives change? Would there be developmental differences? And would there be false details of memory?

METHOD

The authors set out to compare the memories of 153 children from Concord, N.H. (who watched the explosion on television), and Porterville, Calif. (who heard about it). The structured-interview responses of involved and less involved children; latency-age versus adolescent children; and those seen initially (5-7 weeks after the explosion) versus those same children seen later (at 14 months) were statistically compared.

RESULTS

The vast majority of children's memories of Challenger were clear, consistent, and detailed, with highlighting of personal placement, who else was there, and personal occurrences linked to the event. Those children who were less emotionally involved demonstrated significantly less clarity, consistency, and correct ordering of sequences and were less likely to remember personal placement, other people who were there, and related personal incidents. About 30% of all children in this study misunderstood something about Challenger and incorporated these misunderstandings into their memories as false details. Latency-age children continued to harbor false details for 14 months, as opposed to the adolescents.

CONCLUSIONS

Childhood memories of the Challenger space shuttle explosion appeared predictable, were related to patterns of memory that have been observed following single, unrepeated traumas, and reflected age and stage differences.

Lymphoma and luekemia in rheumatoid arthritis: are they associated with azathioprine, cyclophosphamide, or methotrexate?

Incident cases of lymphoma and leukemia in a cohort of 3824 rheumatoid arthritis (RA) patients from the Arthritis, Rheumatism and Aging Medical Information System (ARAMIS) database were identified, and the use of azathioprine, cyclophosphamide, and methotrexate was compared in a matched case-control study. Controls were matched on age, sex, year of study entry, disease duration, center, and years of follow-up. Twenty-four cases of lymphoma and 10 cases of leukemia were identified: 21% of patients with cancer versus 9% of controls had taken azathioprine [McNemar statistic 1.50 (p = 0.22), odds ratio 5.0 (95% confidence interval 0.6,236.5)]. Equal numbers of cases and controls (6% each) had taken cyclophosphamide and 18% of cases and 12% of controls had taken methotrexate [McNemar statistic 0.13 (p = 0.72), odds ratio 1.7 (0.3, 10.7)]. Results suggest but do not prove that RA patients taking azathioprine and methotrexate may have an increased risk of developing lymphoma. However, even if this increased risk can be confirmed, it accounts for only a small proportion of the greatly increased incidence of these malignancies in RA.

Trends in asthma therapy in the United States: 1965-1992

BACKGROUND

Many recent studies indicate an increasing morbidity and mortality of asthma in the past two decades. This study uses data from the National Disease and Therapeutic Index (NDTI) to document and analyze trends in drug therapy for asthma in the United States from 1965 through 1992.

METHODS

The NDTI maintains a continuous rotating national sampling of approximately 1% of US physicians in office-based practice proportionately representative of practicing generalists and specialists who report issuance of drugs in treatment by diagnosis for all patient encounters for a period of two days every 3 months. Annual summaries of five demographic categories and 14 drug categories, characterizing the asthma patient-physician encounters as percent of visits for the 28-year period of 1965 through 1992 are analyzed and characterized.

RESULTS

Physician visits for asthma treatment have shifted somewhat from generalists to specialists in internal medicine and pediatrics. Allergists treat a significant proportion of the asthmatic population. Most patients are seen in the office. There has been no significant change in rates of inpatient visits. Age distribution of the population of patient visits for asthma has been stable, but there is a steady drop in ratio of males to females. Since the mid-1970s, inhaled adrenergic bronchodilator prescriptions have been issued at a markedly increasing rate. Concurrently, issuance of xanthines and oral adrenergic drugs also rose dramatically but then decreased beginning in the mid-1980s. Corticosteroids are used in 15% to 20% of visits, but only recently has the inhaled route of administration shown prominence. Allergen immunotherapy for asthma has decreased more than 10-fold. Cromolyn is prescribed infrequently.

CONCLUSIONS

Major changes have occurred in drug treatment by physicians for asthma in the US since 1965. Bronchodilating drugs predominate, and they are being prescribed in more effective forms at a generally increasing rate. Corticosteroid use has increased at a slower rate and in smaller proportion of patient-visits, while allergen immunotherapy has dramatically declined. The male-to-female ratio of asthmatic patients who visit doctors for treatment appears to be decreasing.

Long-term survival of patients with giant cell arteritis in the American College of Rheumatology giant cell arteritis classification criteria cohort

OBJECTIVE

To characterize survivorship among patients with giant cell arteritis in a well-defined, multicenter cohort.

PATIENTS AND METHODS

Follow-up was obtained for 205 (95.8%) of the 214 patients enrolled in the 1990 American College of Rheumatology vasculitis classification study. Standardized mortality ratios (SMR) were calculated comparing mortality data from this group of patients with giant cell arteritis versus the general population.

RESULTS

There were 49 deaths (33 women and 16 men among the 205 patients available for follow-up. Survivorship was virtually identical to that of the general population (SMR = 1.034 +/- 0.121), and was similar for women (SMR = 1.022 +/- 0.149) and men (SMR = 1.078 +/- 0.206) (SMR = 1 indicates that expected and observed survival are identical).

CONCLUSION

The life expectancy of patients with giant cell arteritis is the same as that of the general population.

Concurrent validity of the Health Assessment Questionnaire Disability Index in Scleroderma

OBJECTIVE

To establish the concurrent validity of the Health Assessment Questionnaire (HAQ) Disability Index in systemic sclerosis (SSc; scleroderma).

METHODS

Eighty subjects with SSc completed the HAQ Disability Index questionnaire. An occupational therapist, who was blind to the subjects' responses, observed each subject's performance on 10 of the items.

RESULTS

Paired t-tests showed significant differences between the observer and subjects' responses for tying shoes, buttoning, gripping, and walking. Intra-class correlations between observer and subjects ranged from 0.38 to 0.76.

CONCLUSION

The results support the validity of the HAQ Disability Index in patients with systemic sclerosis.

A longitudinal study of functional disability in a national cohort of patients with polymyositis/dermatomyositis

OBJECTIVE

To analyze changes in functional status and the factors contributing to disability in a national inception cohort of 257 patients with polymyositis/dermatomyositis (PM/DM).

METHODS

Data were gathered from patients' self-reports on questionnaires: one concerning disease- and treatment-related complications, and the other concerning disability, as reflected by a disability index (DI) derived from the Health Assessment Questionnaire (HAQ).

RESULTS

Based on certain characteristics that differentiated disability patterns, 3 groups of patients were identified. Group 1 patients (n = 153) were < or = 60 years old and never had avascular necrosis (AVN) or a vertebral compression fracture (CF), Group 2 patients were > 60 and never had AVN or a vertebral CF, and Group 3 patients reported AVN or a vertebral CF irrespective of age. As measured by the HAQ DI, disability increased very gradually over time in Group 1 patients and more rapidly in Group 2 and Group 3 patients. The increase in disability in patients experiencing AVN was greater than that in patients with similar pre-AVN disease characteristics who did not develop AVN (P = 0.003).

CONCLUSION

In this prospective study of disease course and iatrogenic factors related to functional disability in PM/DM, the HAQ DI increased with disease duration. Corticosteroid-related morbidity, as reflected by the development of AVN or CF, significantly contributed to patient-reported functional disability.

Comparing the bivariate effects of toxicity and efficacy of treatments

Medical studies often involve comparing the toxicity and efficacy of drugs. Separately evaluating toxicity and efficacy, the usual practice, does not correspond to how doctors manage patients and does not use the information provided in their bivariate relationship. This paper presents methods for analysing the bivariate data. One method is based on assessing the benefit for patient values to lie in different regions of the toxicity-efficacy plane. A second method includes patient thresholds for tolerating drugs. We propose dividing the toxicity-efficacy plane into regions where patients are likely to tolerate the drug. Several statistics are defined on these regions for measuring the toxic-therapeutic relationship, and the bootstrap is proposed for estimating their variances. We illustrate with treatment information available on rheumatoid arthritis patients.

Assessment of living renal donors with spiral CT

PURPOSE

To determine whether spiral computed tomography (CT) can be used to evaluate potential living renal donors.

MATERIALS AND METHODS

Twelve potential living renal donors underwent spiral CT and conventional arteriography. CT angiography was performed with 30-second spiral acquisition during injection of 150 mL of nonionic iodinated contrast material into an antecubital vein at 5 mL/sec. Five minutes after injection, a frontal abdominal scout projection was obtained to assess the renal collecting system. Results of blinded interpretations of axial CT angiograms, three-dimensional CT angiograms, and conventional arteriograms were correlated with intraoperative findings in 11 cases.

RESULTS

Axial and three-dimensional CT angiography were 100% sensitive for identifying seven accessory renal arteries and 14% and 93% sensitive for identifying five prehilar renal artery branches. Renal venous anomalies were confirmed in three patients at surgery. Operative management changed in four of 11 patients who underwent donor nephrectomy.

CONCLUSION

Spiral CT holds promise as a single examination for anatomic assessment of living renal donors.

Discordant effects of dietary L-arginine on vascular structure and reactivity in hypercholesterolemic rabbits

We investigated the effect of dietary supplementation of L-arginine (L-Arg), the precursor of endothelial nitric oxide (NO), on endothelium-dependent and endothelium-independent vascular responses, as well as vascular structure, in the abdominal aorta of hypercholesterolemic rabbits. Rabbits were fed (a) normal rabbit chow, (b) 1% cholesterol diet, or (c) 1% cholesterol diet supplemented with 2.25% L-Arg HCl in drinking water. After 10 weeks, the abdominal aorta was harvested for study of vascular reactivity and histomorphometry. L-Arg did not affect serum cholesterol levels. Histomorphometric analysis demonstrated an eightfold reduction in intimal thickening in the abdominal aorta of the arginine-supplemented hypercholesterolemic rabbits. By contrast, the effects on vascular reactivity were subtle. Contraction to norepinephrine (NE) was not altered by hypercholesterolemia or L-Arg. Contraction to acetylcholine (ACh) was increased in hypercholesterolemic animals; this was normalized by dietary arginine supplementation. Relaxation to nitroglycerin (NTG) was not altered by hypercholesterolemia but was attenuated in the arginine-supplemented rabbits. Endothelium-dependent relaxation to ACh was impaired in both hypercholesterolemic groups. Dietary L-Arg has a dramatic antiatherogenic effect in hypercholesterolemic rabbits. This effect is associated with rather slight changes in vascular reactivity that are suggestive of a slight increase in NO elaboration by the endothelium. The discordance between the effects of dietary arginine on vascular structure and reactivity suggests that the antiatherogenic effects of the NO precursor may not be mediated entirely by its effect on the endothelium.

Minimum data needed on patient preferences for accurate, efficient medical decision making

Involving patients in their health care decisions improves patient satisfaction and outcomes, but can be costly because of the materials and time needed to discuss the many issues that constitute a medical problem. The authors present a framework for identifying the minimum data needed on patient preferences for accurate medical decision making. The method is illustrated for the decision of whether patients with end-stage renal disease should undergo short or long hemodialysis treatments. The value of health states to patients was modeled as a function of six outcomes: survival, uremic symptoms, hospital days per year, the inconvenience associated with long dialysis treatment duration, presence of hypotension during dialysis, and presence of other symptoms during dialysis. The relative importance of each outcome was characterized in a value function by weights referred to as preference-scaling factors. These factors were varied at random over a uniform distribution to simulate different patterns of patient preferences on the six outcomes. The decision model's recommendation was recorded for each simulation. Classification and regression-tree (CART) and stepwise logistic regression analyses were applied to these recommendations to determine the scaling-factor levels that predict short or long treatments. Knowledge of scaling factors on only the inconvenience of long dialysis treatment duration, the worst alive state of health on hemodialysis, and presence of hypotension identified the correct treatment in more than 97% of simulations. Fifty-five patients undergoing hemodialysis were then surveyed for their scaling factors on the six dimensions of well-being. When patients' scaling factors were applied to the predictive rule generated by CART using simulated scaling factors, more than 94% of treatment decisions were classified correctly--sensitivity and specificity of predicting long dialysis were 89% and 100%, respectively. These statistical techniques applied to results of a decision model help identify the minimum data needed on patient preferences to involve patients in efficient and accurate decisions about their health care.

Physical disability in older runners: prevalence, risk factors, and progression with age

BACKGROUND

Concern exists that certain types of exercise, particularly vigorous activity, may increase physical disability among older individuals. We investigated the prevalence of, and risk factors for, physical disability in active older persons (runners), and examined factors influencing the progression of physical disability with age.

METHODS

Physical disability, measured using the Health Assessment Questionnaire Disability Index, was assessed prospectively in 454 runners, age 50 or greater, over five to seven years by annual mailed questionnaires. Baseline sociodemographic, clinical, and life-style characteristics associated with the presence of any disability over the course of the study were determined and contrasted with those in 292 older non-runners who had been similarly followed.

RESULTS

Two hundred twenty-two runners (49%) reported some physical disability during the study. The presence of arthritis symptoms at baseline was the most important risk factor for physical disability; older age, greater body mass index, strenuous work-related physical activity, and the use of more medications were also associated with a greater likelihood of physical disability. Among the non-runners, 224 (77%) reported some physical disability, and the presence of arthritis symptoms was also the most important risk factor for physical disability in this group. Age-related changes in physical disability differed between those with and without arthritis symptoms in both the runner and non-runner groups.

CONCLUSIONS

The presence of arthritis symptoms was an important risk factor for physical disability among both older runners and non-runners, and also identified subgroups of individuals with different progressions of disability with age.

Decreasing costs and improving outcomes in systemic lupus erythematosus: using regression trees to develop health policy

OBJECTIVE

To characterize patients with systemic lupus erythematosus (SLE) who are expected to experience the highest direct and indirect monetary costs and greatest diminished productivity so that we may intervene to reduce costs and improve outcomes.

METHODS

We assessed demographics and health status in January, 1990 and costs incurred in the last 6 months of 1990 in January, 1991 in 151 patients with SLE enrolled in the Montreal General Hospital Lupus Registry. We used regression trees to separate low from high cost patients.

RESULTS

Patients with poor physical or poor psychological functioning incur the highest direct costs (3-fold and 1.6-fold the group mean, respectively); those with the poorest psychological functioning incur the highest indirect costs (2-fold the group average); and those with the most intense pain experience the greatest impairment in productivity (3-fold the group average).

CONCLUSION

Targeting patients with poor physical and psychological functioning and substantial pain with appropriate interventions may improve their outcomes and reduce disease costs. Targeting patients expected to have low costs with preventative interventions may delay worse outcomes and reduce future costs.

Two o-type oxidases in Methylobacillus flagellatum KT

Two oxidases of the o-type in membranes of the methanol-grown obligate methylotroph Methylobacillus flagellatum KT were distinguished. For this purpose the kinetic analysis of the laser flash-induced optical absorbance changes of CO-oxidase complexes under reducing conditions was used. The ratio of these oxidases in membranes greatly depended on the phases of bacterial growth. One of the oxidases appeared to belong to the Escherichia coli o-type oxidase family being more sensitive to KCN (Ki = 1 microM). It showed monophasic CO recombination kinetics with tau 25-30 ms and was expressed in the early exponential phase of growth. The other oxidase seemed to be similar to the Bacillus sp. FTU o-type oxidase being less sensitive to KCN (Ki = 6 microM), having three-phasic CO reassociation kinetics with tau 35-70 microseconds, 0.25-0.5 ms and 2-4 ms and dominating in the stationary growth phase. Pyridine haemochrome spectra showed haems A and D to be absent from the bacterial membranes.

Development of a physical performance and mobility examination

OBJECTIVE

To develop and validate the Physical Performance and Mobility Examination (PPME), an observer-administered, performance-based instrument assessing 6 domains of physical functioning and mobility for hospitalized elderly.

DESIGN

Development of a pass-fail and 3-level scoring system and training manuals for the PPME instrument for use in both clinical and research settings. Two patient samples were used to assess construct validity and interrater reliability of the PPME. A third sample was selected to assess the test-retest reliability of the instrument.

SETTING/PATIENTS

(1) 146 subjects > or = 65 years of age with impaired mobility admitted to Medical Units of Stanford University Hospital. (2) 352 subjects > or = 65 admitted to acute Medical and Surgical Services of the Palo Alto VA Medical Center. Patient samples were obtained during hospitalization and followed until 3 months post-discharge. To study test-retest reliability, 50 additional patients, whose clinical condition was stable, were selected from both settings.

METHODS

An expert panel selected 6 mobility tasks integral to daily life: bed mobility, transfer skills, multiple stands from chair, standing balance, step-up, and ambulation. Tasks were piloted with frail hospitalized subjects for appropriateness and safety. Test-retest and interrater reliability and construct validity were evaluated. Construct validity was tested using the Folstein Mini-Mental State Examination, Activities of Daily Living (ADL), Instrumental Activities of Daily Living (IADL), Geriatric Depression Scale, and modified Medical Outcomes Study Measure of Physical Functioning (MOS-PFR). Two scoring schema were developed for each task: (1) dichotomous pass-fail and (2) 3-level high pass, low pass, and fail. A summary scale was developed for each method of scoring.

MAIN RESULTS

High interrater reliability and intrarater reliability were demonstrated for individual tasks. The mean percent agreement (interrater) for each pass/fail task ranged from 96 to 100% and from 90 to 100% for the 3 pairs of raters for each task using the 3-level scoring. Kappas for individual pairs of raters ranged from .80 to 1.0 for pass-fail scoring and from .75 to 1.0 for 3-level scoring (all P < 0.01). Intraclass correlation coefficients for 3-level scoring by pairs of raters ranged from .66 to 1.0. For summary scales, the mean intraclass correlation was .99 for both scoring schema. Test-retest reliability for summary scales using kappa coefficients was .99 for both pass-fail and 3-level scoring, and .99 and .98, respectively, using Pearson Product Moment Correlation. Correlations of PPME with other instruments (construct validity) suggest that the PPME adds a unique dimension of mobility beyond that measured by self-reported ADLS and physical functioning, and it is not greatly influenced by mood or mental status (r = 0.70 (ADL), r = 0.43 (IADL), r = 0.36 (MMSE), r = 0.71 (MOS-PFR), r = 0.23 (GDS)). The 3-level summary scale was sensitive to the variability in the patient population and exhibited neither ceiling nor floor effects.

CONCLUSIONS

The PPME is a reliable and valid performance-based instrument measuring physical functioning and mobility in hospitalized and frail elderly.

Application of neural networks to the classification of giant cell arteritis

OBJECTIVE

Neural networks are a group of computer-based pattern recognition methods that have recently been applied to clinical diagnosis and classification. In this study, we applied one type of neural network, the backpropagation network, to the diagnostic classification of giant cell arteritis (GCA).

METHODS

The analysis was performed on the 807 cases in the vasculitis database of the American College of Rheumatology. Classification was based on the 8 clinical criteria previously used for classification of this data set: 1) age > or = 50 years, 2) new localized headache, 3) temporal artery tenderness or decrease in temporal artery pulse, 4) polymyalgia rheumatica, 5) abnormal result on artery biopsy, 6) erythrocyte sedimentation rate > or = 50 mm/hour, 7) scalp tenderness or nodules, and 8) claudication of the jaw, of the tongue, or on swallowing. To avoid overtraining, network training was terminated when the generalization error reached a minimum. True cross-validation classification rates were obtained.

RESULTS

Neural networks correctly classified 94.4% of the GCA cases (n = 214) and 91.9% of the other vasculitis cases (n = 593). In comparison, classification trees correctly classified 91.6% of the GCA cases and 93.4% of the other vasculitis cases. Neural nets and classification trees were compared by receiver operating characteristic (ROC) analysis. The ROC curves for the two methods crossed, indicating that the better classification method depended on the choice of decision threshold. At a decision threshold that gave equal costs to percentage increases in false-positive and false-negative results, the methods were not significantly different in their performance (P = 0.45).

CONCLUSION

Neural networks are a potentially useful method for developing diagnostic classification rules from clinical data.

The mortality of rheumatoid arthritis

OBJECTIVE

To determine the risk and causes of death and to quantify mortality predictors in patients with rheumatoid arthritis (RA).

METHODS

RA patients (n = 3,501) from 4 centers (Saskatoon n = 905, Wichita n = 1,405, Stanford n = 886, and Santa Clara n = 305) were followed for up to 35 years; 922 patients died.

RESULTS

The overall standardized mortality ratio (SMR) was 2.26 (Saskatoon 2.24, Wichita 1.98, Stanford 3.08, Santa Clara 2.18) and increased with time. Mortality was strikingly increased for specific causes: infection, lymphoproliferative malignancy, gastroenterologic, and RA. In addition, as an effect of the SMR of 2.26, the expected number of deaths was increased nonspecifically across all causes (except cancer), with a large excess of deaths attributable to cardiovascular and cerebrovascular diseases. Independent predictors of mortality included age, education, male sex, function, rheumatoid factor, nodules, erythrocyte sedimentation rate, joint count, and prednisone use.

CONCLUSION

Mortality rates are increased at least 2-fold in RA, and are linked to clinical severity.