Genetic Variations in TrkB.T1 Isoform and Their Association with Somatic and Psychological Symptoms in Individuals with IBS

Irritable bowel syndrome (IBS), a disorder of gut-brain interaction, is often comorbid with somatic pain and psychological disorders. Dysregulated signaling of brain-derived neurotrophic factor (BDNF) and its receptor, tropomyosin-related kinase B (TrkB), has been implicated in somatic-psychological symptoms in individuals with IBS. Thus, we investigated the association of 10 single nucleotide polymorphisms (SNPs) in the regulatory 3' untranslated region (UTR) of NTRK2 (TrkB) kinase domain-deficient truncated isoform (TrkB.T1) and the BDNF Val66Met SNP with somatic and psychological symptoms and quality of life in a U.S. cohort (IBS n=464; healthy controls n=156). We found that the homozygous recessive genotype (G/G) of rs2013566 in individuals with IBS is associated with worsened somatic symptoms, including headache, back pain, joint pain, muscle pain, and somatization as well as diminished sleep quality, energy level and overall quality of life. Validation using U.K. BioBank (UKBB) data confirmed the association of rs2013566 with increased likelihood of headache. Several SNPs (rs1627784, rs1624327, rs1147198) showed significant associations with muscle pain in our U.S. cohort. Notably, these SNPs are predominantly located in H3K4Me1-enriched regions, suggesting their enhancer and/or transcription regulation potential. Together, our findings suggest that genetic variation within the 3'UTR region of the TrkB.T1 isoform may contribute to comorbid conditions in individuals with IBS, resulting in a spectrum of somatic and psychological symptoms that may influence their quality of life. These findings advance our understanding of the genetic interaction between BDNF/TrkB pathways and somatic-psychological symptoms in IBS, highlighting the importance of further exploring this interaction for potential clinical applications.

The effects of an aviation-style computerised pre-induction anaesthesia checklist on pre-anaesthetic set-up and non-routine events

This prospective, observational study compared the proportion of cases with missing critical pre-induction items before and after the implementation of an aviation-style computerised pre-induction anaesthesia checklist. Trained observers recorded the availability of critical pre-induction items and evaluated the characteristics of the pre-induction anaesthesia checklist performance including provider participation and distraction level, resistance to the use of the checklist and the time required for completion. Surgical cases that met the criteria for inclusion in the National Surgical Quality Improvement Program at a single academic hospital were selected for observation. A total of 853 cases were observed before and 717 after implementation of the checklist. The proportion of cases with failure to perform all pre-induction steps decreased from 10.0% to 6.4% (p = 0.012). There was also a significant decrease in the proportion of cases with non-routine events from 1.2% cases before to none after checklist implementation (p = 0.003). In 17 cases, the checklist alerted the anaesthesia provider to correct a mistake in pre-induction preparation.

Stool and urine trefoil factor 3 levels: associations with symptoms, intestinal permeability, and microbial diversity in irritable bowel syndrome

Previously we showed that urine trefoil factor 3 (TFF3) levels were higher in females with irritable bowel syndrome (IBS) compared to non-IBS females. To assess if TFF3 is associated with symptoms and/or reflect alterations in gastrointestinal permeability and gut microbiota in an IBS population, we correlated stool and urine TFF3 levels with IBS symptoms, intestinal permeability, stool microbial diversity and relative abundance of predominant bacterial families and genera. We also tested the relationship of stool TFF3 to urine TFF3, and compared results based on hormone contraception use. Samples were obtained from 93 females meeting Rome III IBS criteria and completing 4-week symptom diaries. TFF3 levels were measured by ELISA. Permeability was assessed with the urine lactulose/mannitol (L/M) ratio. Stool microbiota was assessed using 16S rRNA. Stool TFF3, but not urine TFF3, was associated positively with diarrhoea and loose stool consistency. Higher stool TFF3 was also associated with lower L/M ratio and microbial diversity. Of the 20 most abundant bacterial families Mogibacteriaceae and Christensenellaceae were inversely related to stool TFF3, with only Christensenellaceae remaining significant after multiple comparison adjustment. There were no significant relationships between stool or urine TFF3 levels and other symptoms, nor between stool and urine levels. In premenopausal females, urine TFF3 levels were higher in those reporting hormone contraception. Collectively these results suggest that higher stool TFF3 levels are associated with IBS symptoms (loose/diarrhoeal stools), lower gut permeability, and altered stool bacteria composition (decreased diversity and decreased Christensenellaceae), which further suggests that TFF3 may be an important marker of host-bacteria interaction.

Heart rate variability is related to pain severity and predominant bowel pattern in women with irritable bowel syndrome

This study examined heart rate variability (HRV) in women with irritable bowel syndrome (IBS) to determine its association with gut pain and predominant bowel pattern. Women with IBS (constipation predominant n = 45, diarrhoea predominant n = 64, alternating n = 56) and healthy controls (n = 50) were recruited from the community. Severity of gut pain was measured retrospectively. The HRV (24 h) was summarized as high-frequency (HF) power and the ratio of low-frequency (LF) power to HF power. Among those women with IBS who have severe gut pain, the 15 constipation-predominant women had lower (P = 0.01) HF power and higher (P = 0.003) LF/HF ratio (geometric means 70 and 7.5, respectively) than the 21 women with diarrhoea-predominant IBS (286 and 3.1) and controls (224 and 3.9). In contrast, among women without severe pain, there is a smaller and not quite significant difference in the opposite direction. Using a broader definition of pain severity based on several questions nearly doubles the number of subjects in the severe pain group and shows even more significant results. The relationship of predominant bowel pattern to HRV is qualitatively different in the subgroup of patients with more severe pain than in the subgroup with less severe pain.

Subjective and objective sleep indices in women with irritable bowel syndrome

Patients with irritable bowel syndrome (IBS) commonly report sleep disturbances. This study examined self-report (Pittsburgh Sleep Quality Inventory) sleep quality and polysomnography (PSG) sleep variables in 18 women with mild-to-moderate IBS, 18 with severe IBS and 38 with age- and gender-matched controls. All women were studied on two consecutive nights in a sleep research laboratory where PSG data were collected. Retrospective and daily measures were obtained of self-reported sleep quality, psychological distress and gastrointestinal symptoms across one menstrual cycle. Self-report measures of psychological distress and sleep quality were significantly worse in the IBS-severe (IBS-S) group compared with controls. Rapid eye movement (REM) latency was higher in the two IBS groups on Night 1 than the control group (P = 0.06). Percentage time in REM was highest in the IBS-S on Night 2. All groups demonstrated greater sleep disruption on Night 1 (adaptation) when compared with Night 2. These results highlight the importance of considering the 'first-night effect' in those with IBS and the lack of concordance between self-report and objective indices of sleep in women with IBS.

Relationship of cerebral perfusion pressure levels to outcome in traumatic brain injury

This study examined the relationship of cumulative percent time that cerebral perfusion pressure (CPP) fell below set thresholds to outcome in individuals with traumatic brain injury (TBI). The sample included 157 patients (16 to 89 years of age, 79%, male) admitted to an intensive care unit at an academic medical center who underwent invasive arterial blood pressure and intracranial pressure monitoring. CPP levels were recorded continuously during the first 96 hours of monitoring. Initial neurologic status was assessed using the post-resuscitation Glasgow Coma Scale. Outcome was evaluated at hospital discharge and at six months post-injury using the Extended Glasgow Outcome Scale (GOSE). The relationship of cumulative periods of low CPP to outcome was evaluated using hierarchical and binary logistic regression analysis, controlling for age, gender, and injury severity. Patients experiencing less cumulative percent time below specific CPP thresholds were more likely to have better outcome at discharge (55 mm Hg, p = .004; 60 mm Hg, p = .008; 65 mm Hg, p = .024; 70 mm Hg, p = .016). Although differences in GOSE scores at six months were not significant, those with less time below CPP thresholds were more likely to survive. Accumulated episodes of low CPP had a stronger negative relationship with outcome in patients with more severe primary brain injury.

Nociceptive and neuropathic pain in patients with lung cancer: a comparison of pain quality descriptors

Predictive validity of each word from the McGill Pain Questionnaire (MPQ) has not been investigated in relation to pain etiology. The purpose of this study was to explore differences in the words used to describe nociceptive and neuropathic pain. Patients with lung cancer (N = 123) selected words from the 78 MPQ pain quality descriptors and indicated the corresponding pain site for each word. Using only the MPQ pain location, and the cancer and treatment data abstracted from medical records, each pain site was classified as nociceptive or neuropathic (etiology). Pain etiology and quality descriptors were tested for proportional differences with sensitivity, specificity, and predictive value calculated for statistically significant descriptors. Of the 457 pain sites, 343 were classified as nociceptive (75%), 114 as neuropathic (25%). Lacerating, stinging, heavy, and suffocating were selected for a significantly larger proportion of nociceptive sites whereas throbbing, aching, numb, tender, punishing, pulling, tugging, pricking, penetrating, punishing, miserable, and nagging were selected for a larger proportion of neuropathic sites. Ten words correctly predicted 78% of the sites with 81% sensitivity to nociceptive pain and 59% sensitivity to neuropathic pain. Interestingly, several pain quality descriptors (burning, shooting, flashing, tingling, itching, and cold) previously associated with neuropathic pain did not distinguish between neuropathic and nociceptive pain. Infrequent selection of many MPQ words and lack of neurological exam data in the medical records are possible explanations for inconsistency with previous literature. Prospective studies are needed to validate pain quality descriptors for nociceptive and neuropathic types of lung cancer pain.

Autonomic nervous system function in women with irritable bowel syndrome

Autonomic nervous system (ANS) balance was assessed in women with and without irritable bowel syndrome (IBS) using laboratory tests of function (ie, expiratory/inspiratory ratio, Valsalva, posture changes, and cold pressor) and spectral and nonspectral measures of heart rate variability (HRV). Women with (N = 103) and without IBS (N = 49) were recruited, interviewed, then completed a laboratory assessment and wore a 24-hr Holter monitor Analysis using the entire sample showed little difference between IBS and control women and between subgroups with IBS on either laboratory measures or 24-hr HRV measures. However, analysis restricted to those women with severe IBS symptoms showed quite pronounced differences between two IBS subgroups on 24-hr HRV measures. Parasympathetic tone was significantly lower and ANS balance was significantly higher in the constipation-predominant compared to the diarrhea-predominant group. Subgroups of women with IBS do differ in ANS function as measured by 24-hr HRV; however, these differences are only apparent among women with severe symptoms. These findings point out the importance of considering symptom severity when interpreting studies of IBS.

Comparison of autonomic nervous system indices based on abdominal pain reports in women with irritable bowel syndrome

Abdominal pain is an important symptom in irritable bowel syndrome (IBS), but patients report typical pain intensities ranging from mild to very severe. In a sample of women, the authors sought to determine whether measures of systemic autonomic activity are related to self-reported pain intensity and the occurrence of pain in the postprandial period. One hundred and six women with IBS and 41 controls completed bowel symptom and psychological distress questionnaires and wore 24-h Holter electrocardiogram monitors to estimate global heart rate variability measures of parasympathetic activity and sympathetic nervous system/parasympathetic nervous system balance. About one-third of the IBS sample reported severe or very severe abdominal pain (n = 34/106), and about one-half of the IBS sample reported postprandial pain (n = 52/106). Even after statistically controlling for age, body mass index, and psychological distress, vagal heart rate variability measures were markedly lower in women reporting high pain (P < 0.01) and markedly higher in women reporting postprandial pain (P < 0.02). The vagal component of heart rate variability appears to be reduced in women with severe abdominal pain, especially in those whose pain is not postprandial.

Sleep disturbance influences gastrointestinal symptoms in women with irritable bowel syndrome

This analysis evaluated the association between sleep disturbance and gastrointestinal symptoms in women with and without irritable bowel syndrome (IBS), and examined the role of psychological distress in this relationship. Women with IBS (N = 82) reported considerably higher levels of sleep disturbance compared to controls (N = 35), using both retrospective seven-day recall and daily diary recall for two menstrual cycles (P < 0.05 on 8 of 10 measures). We used daily diary data to estimate the association between sleep disturbance and gastrointestinal symptoms, both across women (ie, whether women with high average sleep disturbance have higher average gastrointestinal symptoms) and within woman (ie, whether poorer than average sleep on one night is associated with higher than average gastrointestinal symptoms the following day). The regression coefficients for the across-women effect are large and highly significant in both groups (IBS, beta +/- SE = 0.46 +/- 0.08, P < 0.001; controls, 0.57 +/- 0.13, P < 0.001). The regression coefficients for the within-woman effect are considerably smaller and statistically significant only in the IBS group (IBS, 0.06 +/- 0.02, P = 0.006; control, 0.01 +/- 0.03, P = 0.691). These regression coefficients showed little change when daily psychological distress or stress was controlled for, the one exception being the coefficient for the across-women effect in the IBS group, which decreased substantially but still remained highly significant. Because it is possible that gastrointestinal symptoms could, in fact, cause poor sleep, we also fitted the temporally reversed model to evaluate the association between gastrointestinal symptoms on one day and sleep disturbance that night. The within-woman regression coefficients were nonsignificant in both the IBS and control groups. In conclusion, these results are consistent with the hypothesis that poor sleep leads to higher gastrointestinal symptoms on the following day among women with IBS.

Preferences for Life-Sustaining Treatments in Advance Care Planning and Surrogate Decision Making

BACKGROUND

Surrogates and clinicians often make treatment decisions for decisionally incapacitated patients with limited knowledge of their preferences. This study examined patients' life-sustaining treatment preferences to facilitate advance care planning discussions and surrogate decision making.

METHODS

We interviewed 342 participants from 7 groups: younger and older well adults; persons with chronic illness, terminal cancer, and acquired immunodeficiency syndrome (AIDS); stroke survivors; and nursing home residents. Preferences for antibiotics, short- and long-term mechanical ventilation, hemodialysis, tube feeding, and cardiopulmonary resuscitation (CPR) were elicited for each participant's current health state and three hypothetical health states representing severe dementia, coma, and severe stroke.

RESULTS

Participants chose to forego more invasive or long-term treatments at a higher rate than less invasive, short-term treatments in all health states. Participants were much more willing to forego treatments in coma than in their current health state, with stroke and dementia somewhere in between. Participants who were older, female, had worse functional status, had more depressive symptoms, or lived in a nursing home were more inclined to forego treatment in their current health state. In contrast, treatment preferences in hypothetical health states showed either no associations or much weaker associations with these factors. Participants who were willing to accept more invasive treatments were highly likely to accept less invasive treatments and participants who preferred to forego a less invasive treatment were highly likely to forego more invasive treatments. Participants who preferred to receive a treatment in a health state with severe impairments were highly likely to want the same treatment in a less impaired health state. Similarly, participants who preferred to forego a treatment in a less impaired health state were highly likely to forego the same treatment in a more impaired state.

CONCLUSIONS

In advance care planning discussions, clinicians might explore with patients their preferences about short- and long-term treatments with variability in their invasiveness (including CPR) in both their current health state and hypothetical situations representing different levels of functional impairment. When surrogates have no knowledge about the wishes of formerly competent patients, clinicians may help them with medical decisions by discussing what other people commonly want in similar circumstances.

Bone resorption levels by age and menopausal status in 5,157 women

OBJECTIVE

The purpose of this study was to describe bone resorption activity using a biochemical marker according to the categories of age, menopausal status, and selected drug/supplement use in middle-aged and elderly community-based women.

DESIGN

This was a cross-sectional study that assessed urinary cross-linked N-telopeptide of type I collagen (NTx) and used self-report data to group women as premenopausal (Pre), perimenopausal (Peri), postmenopausal without hormone replacement therapy (Post), and postmenopausal with hormone replacement therapy (HRT).

RESULTS

Mean NTx values were found to be significantly different by group and controlling for age (p = 0.001), with post hoc tests showing all pairwise group comparisons as significantly different (p = 0.001), except that the Pre and HRT groups were not significantly different. Both the Peri and the Post NTx levels were significantly higher than the Pre and the HRT groups'. NTx values in the Peri group varied with age-the youngest Peri women were similar to Pre women, and the oldest Peri women were similar to Post women. Significantly lower NTx levels were found only in the Post (p = 0.009) and HRT (p < 0.001) groups using diuretics compared with nonuse and only in the HRT group using calcium supplements compared with nonuse (p = 0.006). No differences by thyroid use were found. With a biochemical marker, the results showed that bone resorption activity differences could be demarcated in women according to age, estimated menopausal stage, and selected drug/supplement use.

CONCLUSIONS

These results support the usefulness of NTx assessment for indicating bone resorption activity and therefore the potential for osteoporosis or for monitoring the efficacy of antiresorptive therapies.

Parents' health, health care utilization, and health behaviors following the violent deaths of their 12- to 28-year-old children: a prospective longitudinal analysis

Health status, health care utilization, and health behaviors of parents bereaved by the violent deaths of their adolescent and young adult children were examined 4, 12, and 24 months later. Participants were 261 bereaved parents (171 mothers, 90 fathers). About 20% of the parents reported "poor" physical health during the early bereavement period compared with 16% of Americans the same age. Over time, mothers' health improved whereas fathers' health deteriorated. Fathers in poor health compared with fathers in good health are 15 times more likely to report emotional distress and 4.6 times more likely to report trauma symptoms. Mothers in poor health compared with mothers in good health are 11 times more likely to report emotional distress and 3 times more likely to report trauma symptoms. Mothers' reports of physician visits and medication use were higher than fathers', however, mothers' rates for both decreased significantly over time whereas fathers' rates remained constant. Over 70% of the mothers and nearly 60% of the fathers practiced 2 or more health protective behaviors over time--a finding significantly associated with fewer stress-related illnesses, days absent from work, and non-productivity at work. Implications for the findings are discussed.

PTSD among bereaved parents following the violent deaths of their 12- to 28-year-old children: a longitudinal prospective analysis

This study examined the prevalence of posttraumatic stress disorder (PTSD) among parents bereaved by the violent deaths of their 12- to 28-year-old children. A community-based sample of 171 bereaved mothers and 90 fathers was recruited by a review of Medical Examiner records and followed for 2 years. Four important findings emerged: Both parents' gender and children's causes of death significantly affected the prevalence of PTSD symptoms. Twice as many mothers and fathers whose children were murdered met PTSD caseness (full diagnostic) criteria compared with accident and suicide bereavement. Symptoms in the reexperiencing domain were the most commonly reported. PTSD symptoms persisted over time, with 21% of the mothers and 14% of the fathers who provided longitudinal data still meeting caseness criteria 2 years after the deaths. Parents who met caseness criteria for PTSD, compared with those who did not, were significantly different on multiple study variables. Both theoretical and clinical implications for the findings are discussed.

Changes in parents' mental distress after the violent death of an adolescent or young adult child: a longitudinal prospective analysis

This study examined changes in bereaved parents' mental distress following the violent deaths of their 12- to 28-year-old children. A community-based sample of 171 bereaved mothers and 90 fathers was recruited by a review of medical examiner records. Data were collected 4, 12, and 24 months post-death. Repeated measures analysis of variance showed significant reductions in 8 of 10 measures of mental distress among mothers and 4 of 10 for fathers, with the most change for both genders occurring between 4 and 12 months post-death. During the 2nd year of bereavement, mothers' symptoms continued to decline, whereas fathers, who started out with less distress than mothers, reported slight increases in 5 of 10 symptom domains. Nonetheless, 2 years after the deaths, mothers' mental distress scores were up to 5 times higher than those of "typical" U.S. women and fathers' scores were up to 4 times higher than "typical" U.S. men. Of the 7 intervening variables examined, higher scores on self-esteem and self-efficacy predicted lower distress for both mothers and fathers 4, 12, and 24 months post-death. Repressive coping was predictive of distress among fathers. It was concluded that violent death bereavement has sustained, distressing consequences on parents of children who die as a result of accidents, homicides, and suicide.

The effect of expanding Medicaid prenatal services on birth outcomes

OBJECTIVES

Over 80% of US states have implemented expansions in prenatal services for Medicaid-enrolled women, including case management, nutritional and psychosocial counseling, health education, and home visiting. This study evaluates the effect of Washington State's expansion of such services on prenatal care use and low-birthweight rates.

METHODS

The change in prenatal care use and low-birthweight rates among Washington's Medicaid-enrolled pregnant women before and after initiation of expanded prenatal services was compared with the change in these outcomes in Colorado, a control state.

RESULTS

The percentage of expected prenatal visits completed increased significantly, from 84% to 87%, in both states. Washington's low-birthweight rate decreased (7.1% to 6.4%, P = .12), while Colorado's rate increased slightly (10.4% to 10.6%, P = .74). Washington's improvement was largely due to decreases in low-birthweight rates for medically high-risk women (18.0% to 13.7%, P = .01, for adults; 22.5% to 11.5%, P = .03, for teenagers), especially those with preexisting medical conditions.

CONCLUSIONS

A statewide Medicaid-sponsored support service and case management program was associated with a decrease in the low-birthweight rate of medically high-risk women.

The relationship between psychological distress and gastrointestinal symptoms in women with irritable bowel syndrome

BACKGROUND

Individuals with irritable bowel syndrome (IBS) are reported to experience more symptoms compatible with psychopathologic disorders, abnormal personality traits, and psychological distress. Conversely, individuals with psychiatric disorders report higher levels of gastrointestinal (GI) symptoms compatible with IBS. Thus, psychological distress may contribute to GI symptoms in individuals with IBS.

OBJECTIVES

To examine psychological distress in women with IBS, women with similar GI symptoms but not diagnosed (IBS nonpatients, IBS-NP), and asymptomatic Control women.

METHODS

The women (N=97) were interviewed, completed questionnaires, and maintained daily diaries for 2 months. Across-women and within-woman analyses were used to calculate the results.

RESULTS

The IBS and IBS-NP groups had a higher percentage of lifetime psychopathology and recalled psychological distress. At least 40% of the women in the IBS and IBS-NP groups had positive relationships between daily psychological distress and daily GI symptoms.

CONCLUSIONS

Psychological distress is an important component of the IBS symptom experience and should be considered when treatment strategies are designed.

Broad-spectrum group treatment for parents bereaved by the violent deaths of their 12- to 28-year-old children: a randomized controlled trial

This study assessed the efficacy of a 10-week broad-spectrum intervention offered to bereaved parents about 4 months after the deaths of their 12--28-year-old children due to accidents, homicide, or suicide. For three outcomes of distress there was a significant interaction between treatment and baseline values for each outcome for mothers both immediately posttreatment and 6 months later. The intervention appeared to be the most beneficial for mothers most distressed at baseline. Fathers showed no immediate benefits of treatment. Further research is needed to investigate these unexpected results for fathers and to further characterize those who benefit from similar programs.

Validation of preferences for life-sustaining treatment: implications for advance care planning

BACKGROUND

Treatment preferences established before life-threatening Illness occurs may differ from actual decisions because of changes in preferences or poor understanding of the link between prospective preferences and outcomes.

OBJECTIVES

To evaluate the validity of prospective treatment preferences by examining their concordance with ratings of health states.

DESIGN

Survey of seven cohorts of persons with diverse health status. Home- and hospital-based interviews were conducted at baseline and at 6, 18, and 30 months.

SETTING

The greater Seattle area.

PARTICIPANTS

Younger and older well adults; persons with chronic conditions, terminal cancer, or AIDS; stroke survivors; and nursing home residents.

MEASUREMENTS

Concordance between six treatment preferences and five health state ratings (on a seven-point scale) was assessed by using logistic regression to measure the increase in odds of treatment refusal for each one-point change in health state rating. Preferences were considered concordant if treatments were refused in health states rated as worse than death and were accepted in health states rated as better than death. Reasons for discordance were elicited at the final interview.

RESULTS

The probability of refusal of prospective treatment was strongly related to health state ratings. Odds ratios ranged from 1.7 to 1.9 (P < 0.001) for every treatment. When patients were shown their discordant preferences, they had a coherent explanation or changed their health state rating or treatment preference to make the two concordant.

CONCLUSIONS

Prospective life-sustaining treatment preferences show high convergent validity. For most persons, treatment preferences are grounded in a consistent belief system. Concordance and discordance between treatment preferences and health state ratings offer clinicians the opportunity to explore patients' values and reasoning.

Psychophysiological response to a laboratory challenge in women with and without diagnosed irritable bowel syndrome

The purpose of this study was to describe and compare physiological variables at baseline and in response to laboratory stress among women diagnosed with irritable bowel syndrome (IBS, n = 26), women with undiagnosed chronic gastrointestinal symptoms consistent with IBS (IBS-NP, n = 24), and asymptomatic women (n = 22). Urine catecholamine levels were measured in the first voided specimen on the morning of testing. Cardiovascular variables were measured at baseline and repeatedly during the Stroop Color-Word Conflict Test (Stroop). Women in the IBS group had higher baseline systolic blood pressure (SBP) than the control group and higher basal urine norepinephrine (NE) levels than the IBS-NP group. Control for activity or body mass reduced the group difference in SBP to nonsignificance but did not affect the observed difference in urine NE. There were no significant differences among the groups in other baseline values or in response to the Stroop. These results suggest that, despite higher basal urine catecholamine levels, cardiovascular reactivity to a cognitive challenge in a laboratory setting is not elevated in women with diagnosed IBS.

The relationship between daily life stress and gastrointestinal symptoms in women with irritable bowel syndrome

Research on irritable bowel syndrome (IBS), a functional disorder of the gastrointestinal (GI) system, has linked GI symptoms to stress. This study examined the relationship between daily stress and GI symptoms across women and within woman in IBS patients (n = 26), IBS nonpatients (IBS-NP; n = 23), and controls (n = 26), controlling for menstrual cycle phase. Women (ages 20-45) completed daily health diaries for two cycles in which they monitored daily GI symptoms and stress levels. The Life Event Survey (LES) was used as a retrospective measure of self-reported stress. The across-women analyses showed higher mean GI symptoms and stress in the IBS and IBS-NP groups relative to controls but no group differences in LES scores. The within-woman analyses found a significant and positive relationship between daily stress and daily symptoms in both the IBS-NP and the IBS groups. Controlling for menstrual cycle had no substantial impact on the results.

Critical care outcomes: linking structures, processes, and organizational and clinical outcomes

BACKGROUND: Organizational structure and process are thought to affect patient care outcomes beyond the effects of expert clinical care. OBJECTIVES: To test the hypothesis that a discretionary pattern of organizational structure and process factors is predictive of critical care unit performance, ie, desirable patient and organizational outcomes. METHODS: Quality-of-care patient and organizational outcomes were evaluated in 25 critical care units. A single value representing each critical care unit's euclidian distance from a theoretically ideal pattern of discretionary function was determined and correlated with unit-level measures of outcomes (standardized mortality ratio, severity-adjusted length of stay, patient satisfaction, quality of nursing care, and nursing retention). RESULTS: Distance from the ideal-type discretionary pattern predicted organizational but not clinical outcomes. Units closer to the ideal-type pattern had higher RN retention, and were viewed as better places to work, with higher-quality care by both nurses and physicians. Objectively measured quality of care, patient satisfaction, severity-adjusted mortality, and length of stay were not consistently related to better-structured units. CONCLUSIONS: With experienced critical care practitioners, unit-level structure and process factors were better predictors of organizational outcomes than of clinical outcomes.

Critical care outcomes: linking structures, processes, and organizational and clinical outcomes

BACKGROUND

Organizational structure and process are thought to affect patient care outcomes beyond the effects of expert clinical care.

OBJECTIVES

To test the hypothesis that a discretionary pattern of organizational structure and process factors is predictive of critical care unit performance, ie, desirable patient and organizational outcomes.

METHODS

Quality-of-care patient and organizational outcomes were evaluated in 25 critical care units. A single value representing each critical care unit's euclidian distance from a theoretically ideal pattern of discretionary function was determined and correlated with unit-level measures of outcomes (standardized mortality ratio, severity-adjusted length of stay, patient satisfaction, quality of nursing care, and nursing retention).

RESULTS

Distance from the ideal-type discretionary pattern predicted organizational but not clinical outcomes. Units closer to the ideal-type pattern had higher RN retention, and were viewed as better places to work, with higher-quality care by both nurses and physicians. Objectively measured quality of care, patient satisfaction, severity-adjusted mortality, and length of stay were not consistently related to better-structured units.

CONCLUSIONS

With experienced critical care practitioners, unit-level structure and process factors were better predictors of organizational outcomes than of clinical outcomes.

Relationship between gastrointestinal and dysmenorrheic symptoms at menses

The relationship between gastrointestinal (GI) symptoms and uterine cramping pain at menses, controlling for affective states and prostaglandin synthesis inhibitor use, was examined. A total of 53 women completed a daily diary of symptoms, stool characteristics, and medication use for three consecutive menstrual cycles. There were significant across-women and within-woman relationships between stomach pain, nausea, and uterine cramping pain, but not between cramping pain and constipation, diarrhea, or stool characteristics. These results support the presence of a similar mechanism in the generation of distressing GI symptoms and uterine cramping pain at menses.

Advance care planning: eliciting patient preferences for life-sustaining treatment

Patient autonomy is a guiding principle in medical decision-making in America. This is challenging when patients become mentally incapacitated and cannot express their preferences. Advance care planning (ACP) addresses this challenge. ACP is a deliberative and communicative process that helps people formulate and communicate preferences for future medical care in the event of mental incapacity. Advance directives are mechanisms for communicating and/or documenting ACP, and are either instructional (e.g. statement of treatment preferences in living wills) or proxy types (e.g. appointment of another person to speak on the patient's behalf). ACP discussions between patients and health care providers and patient-orientated educational ACP materials often ignore insights from 2 related activities, health promotion and human information processing. More effective ACP should occur with greater attention to the concepts of stages of change and self-efficacy, the Health Belief Model, and the necessary requisites for cognitive integration.

Daily gastrointestinal symptoms in women with and without a diagnosis of IBS

This study compared daily gastrointestinal symptoms and stool characteristics across two menstrual cycles, and recalled bowel symptoms and psychological distress in women with irritable bowel syndrome (IBS, N = 22), IBS nonpatients (IBS-NP, N = 22), and controls (N = 25). Daily reports of abdominal pain, bloating, intestinal gas, constipation, and diarrhea did not differ significantly between the IBS and IBS-NP groups but both groups reported significantly higher symptoms than the control group. Stool consistencies was significantly looser in the IBS group relative to the control group. Menstrual cycle effects on symptoms were noted in all the groups. There were no significant differences in psychological distress between women with IBS and IBS-NP, but both groups reported significantly higher global distress than the control group. The lack of difference between the IBS and IBS-NP groups in contrast to the results of others, can be understood in terms of differences in recruitment strategies.

Do surgical brain lesions present as isolated dementia? A population-based study

OBJECTIVE

To determine the incidence of clinically important subdural hematoma (SDH), hydrocephalus not associated with a recent intracranial bleed, and intracranial tumor that is not obviously metastatic, and to test the sensitivity of a promising decision rule for computerized tomography (CT) in dementia.

DESIGN

Population-based, retrospective, sequential case series.

SETTING

Staff model health maintenance organization (HMO).

PATIENTS

Patients aged 65 years and older with one of the three lesions, diagnosed over a 4.5-year period, identified mainly through computerized databases of hospital discharge diagnoses and a registry of malignant tumors.

MEASUREMENTS

Clinical data were based on chart review. The decision rule, based on one that had been previously proposed and tested, stated that CT would be required if any one of 11 clinical criteria were met by a patient with cognitive impairment. Rule sensitivity was evaluated using clinical information recorded before CT.

MAIN RESULTS

One hundred forty-five clinically important lesions were identified among 137,100 person-years at risk. Average annual incidence per 100,000 was 46.7 (95% CI 36.0, 59.6) for SDH, 5.8 (95% CI 2.5, 11.5) for hydrocephalus not associated with a recent intracranial bleed, and 53.2 (95% CI 41.7, 66.9) for intracranial tumors that were not obviously metastatic. Using the 65 to 74- year age strata as a reference, the relative risk for SDH was 4.8 (95% CI 2.7, 8.5) in 75 to 84-year-olds and 13.1 (95% CI 7.7, 22.5) in the 85 and older strata. Among 59 patients who presented with cognitive impairment, without altered sensorium or physical evidence of trauma, decision rule sensitivity was 93.2% (95% CI 83.5%, 98.1%). Sensitivity was 90.7% (95% CI 77.9%, 97.4%) in the subgroup that presented to an ambulatory care clinic rather than to an emergency department.

CONCLUSIONS

These three lesions, which are the most common surgical lesions that may present as dementia, are rare. Most cases have presentations that easily distinguish them from typical Alzheimer's disease. This case series indicates that it may be feasible to develop a decision rule for the selective use of CT in dementia. Disease spectrum will influence measures of decision rule performance such as sensitivity and specificity.

Firefighters and paramedics: years of service, job aspirations, and burnout

1. Data were collected from an anonymous mail survey of over 2,000 paramedics and firefighters to determine the relationships among years of service and four occupational outcomes, including burnout. 2. Paramedics had poorer outcomes than firefighters. Job title, not percent of emergency service runs per se, significantly differentiated the groups with respect to burnout and job aspiration variables. 3. After adjusting for age, years of service correlated negatively with three measures of job aspirations: job satisfaction, work related morale, and career goal attainment in both groups. 4. If signs and symptoms of burnout occur throughout the worker's life cycle rather than with increasing years of experience, the findings have implications for both prevention and intervention strategies.

Measuring preferences for health states worse than death

Previous research indicates that persons assigning values to ranges of health states consider some states to be worse than death. In a study of decisions regarding life-sustaining treatments, the authors adapted and assessed existing methods for their ability to identify and quantify preferences for health states near to or worse than death in a population of well adults and nursing home residents. The cognitive burdens involved in these decisions were also evaluated. Hypothetical health states based on six attributes of functional status were constructed to describe severe constant pain, dementia, and coma. The methods of rank order, category scaling, time tradeoff, and standard gamble were adapted to quantify states worse than death. Cognitive burden was assessed using completion rates, interviewer assessments, respondents' self-reporting, and investigators' evaluations. For both respondent groups, all methods showed similar degrees of cognitive burden for those able to complete the tasks and were similar in their ability to identify and quantify preferences. The majority of nursing home residents, however, were unable to complete or comprehend the measurement tasks. Most respondents evaluated their current health and severe constant pain as better than death; dementia and coma were more often considered equal to or worse than death. These results indicate that respondents can and do evaluate some health states as worse than death. The authors recommend systematic inclusion of states worse than death to describe a more complete range of preference values and routine assessment of the cognitive burdens of assessment techniques to evaluate methodologies.

Total serum cholesterol levels and mortality risk as a function of age. A report based on the Framingham data

OBJECTIVE

To evaluate the relationship between serum cholesterol level and all-cause, coronary heart disease (CHD), and non-CHD mortality as a function of age.

METHODS

The data source was the biennial examination data from 1948 through 1980 for the 5209 men and women enrolled in the Framingham Heart Study. Age-specific analyses by the Cox proportional hazards regression model were performed of survival subsequent to ages 40, 50, 60, 70, and 80 years for all subjects enrolled and alive at each of the stated ages. Complementary models were studied that used high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, or total cholesterol level as predictors of survival subsequent to the examination at which lipoprotein subfractions were determined (1968) through 1973).

RESULTS

The relationship between total cholesterol level and all-cause mortality was positive (ie, higher cholesterol level associated with higher mortality) at age 40 years, negative at age 80 years, and negligible at ages 50 to 70 years. The relationship with CHD mortality was significantly positive at ages 40, 50, and 60 years but attenuated with age until the relationship was positive, but not significant, at age 70 years and negative, but not significant, at age 80 years. Results for the relationship between low-density lipoprotein cholesterol and high-density lipoprotein cholesterol and mortality help explain these findings. Non-CHD mortality was significantly negatively related to cholesterol level for ages 50 years and above. The negative results in the oldest age group for all-cause and CHD morality appeared to be due to a negative relationship with low-density lipoprotein cholesterol levels rather than the protective effect of high high-density lipoprotein cholesterol levels. Similar results from several modified analyses make low cholesterol level due to severe illness an unlikely explanation for our results.

CONCLUSIONS

Physicians should be cautious about initiating cholesterol-lowering treatment in men and women above 65 to 70 years of age. Only randomized clinical trials in older people can settle the debate over the efficacy and cost-effectiveness of lipid-lowering interventions for reducing mortality and morbidity in this population.

Testing the null hypothesis in small area analysis

The goal of small area analysis is often to demonstrate that hospital admission rates or procedure rates vary greatly among regions, suggesting the occurrence of unnecessary admissions or procedures in some regions. Recent articles have shown that such variation may be largely due to chance, even if no underlying differences exist among the small areas; thus, it is important to test if the observed variation is larger than expected by chance. In this article we discuss how the appropriate method for testing the null hypothesis depends on the distribution of the number of admissions at the person level. If it is not possible for an individual to have more than one admission for a given procedure, the appropriate test is a simple chi-square test. If multiple admissions are possible, a modified chi-square test can be used to account for the excess variability due to multiple admissions. Failure to make the correct modification to the chi-square test in this latter case can result in spurious results. This underscores the importance of collecting data on multiple admissions in order to estimate the distribution of the number of admissions at the individual-patient level.

Can small-area analysis detect variation in surgery rates? The power of small-area variation analysis

A variety of statistical methods can be used in small-area analysis to test whether there is more variation than would be expected by chance alone. However, the power of these methods to detect existing variation has never been studied. The authors used data regarding back surgery in Washington State to suggest several types of variation that might exist (alternative hypotheses), and then used computer simulation to determine the power, or the probability of detecting this variation. The chi-square test had the highest power of all methods considered against most alternative hypotheses. Power is higher if there are no multiple admissions, rates are higher, and counties have larger or similar population size. Problems of accounting for multiple admissions, adjustment for age and sex, choosing the optimum size of small areas, and detection of outliers also are discussed.

Effect of intensive endurance training on lipoprotein profiles in young and older men

Although there are considerable data concerning the effects of endurance exercise training (ET) on plasma lipoproteins, the results have been quite inconsistent. The observed variability of response may be related to the age, sex, adiposity, or diet of the subjects tested, or to the type and intensity of the exercise intervention. Furthermore, there is relatively little such data in older individuals. Therefore, in the present study, we investigated the effects of intensive ET on lipoprotein profiles in healthy young (n = 12; 28.2 +/- 2.4 years) and older (n = 15; 67.5 +/- 5.8 years) men. Unlike subjects in most similar studies, our subjects were weight-stabilized on a constant-composition diet for 21 days prior to determination of the lipoprotein profile before and after the ET program. At baseline, the two groups were not significantly different with respect to any individual component of their lipoprotein profiles, relative weight, or percent body fat, but the older men had a more central distribution of fat by both waist to hip ratio (WHR) and computed tomography (CT). Maximal aerobic power, expressed per kilogram of body weight (VO2 max), was 33% lower (P less than .001) in the older men at baseline. Following the 6-month, walk/jog/bike ET program (5 d/wk), both the young (+18%, P less than .001) and the older (+22%, P less than .001) men increased their VO2 max. This was associated with small, but significant, decrements in weight, percent body fat, and WHR only in the older men.(ABSTRACT TRUNCATED AT 250 WORDS)

Fibrinolytic response during exercise and epinephrine infusion in the same subjects

To determine whether exercise-induced increases in tissue plasminogen activator (t-PA) were related to plasma epinephrine concentration during exercise, 14 healthy men (aged 24 to 62 years) were studied during epinephrine infusions (10, 25 and 50 ng/kg per min) and graded supine bicycle exercise, beginning at 33 W and increasing in 33-W increments until exhaustion. Plasma epinephrine, active and total t-PA, active plasminogen activator inhibitor type 1 (PAI-1) and t-PA/PAI-1 complex concentrations were measured at each exercise and infusion level. During epinephrine infusion, active and total t-PA levels increased linearly with the plasma epinephrine concentration (respective slopes [+/- SEM] of 0.062 +/- 0.003 and 0.076 +/- 0.003 pmol/ng epinephrine). During exercise, t-PA levels did not increase until plasma epinephrine levels increased, after which both active and total t-PA levels again increased linearly with the plasma epinephrine concentration, but at twice the rate observed with epinephrine infusion (0.131 +/- 0.005 and 0.147 +/- 0.005 pmol/ng, respectively). The t-PA level in blood was directly proportional to the plasma epinephrine concentration during both exercise and epinephrine infusion, suggesting that epinephrine release during exercise stimulates t-PA secretion. In these healthy subjects, active plasminogen activator inhibitor type 1 and t-PA/PAI-1 complex levels were low (41 +/- 11 and 21 +/- 5 pmol/liter, respectively) and did not change significantly during exercise or epinephrine infusion. It is concluded that approximately 50% of the increase in t-PA during exercise is due to stimulated release of t-PA by epinephrine.(ABSTRACT TRUNCATED AT 250 WORDS)

Exercise training delineates the importance of B-cell dysfunction to the glucose intolerance of human aging

Aging has been associated with glucose intolerance, insulin resistance, hyperinsulinemia, and diminished islet B-cell function. The relative contribution of these factors to the aging-associated changes in glucose tolerance has been difficult to discern, particularly so for B-cell function, since insulin sensitivity itself is a determinant of B-cell function and, therefore, comparisons of insulin levels and responses between old and young subjects are difficult. To reduce this effect, we compared B-cell function in 14 healthy older men (aged 61-82 yr; body mass index, 21-30 kg/m2), who were exercise trained for 6 months to improve insulin sensitivity, to that of 11 healthy young men (aged 24-31 yr; body mass index, 19-31 kg/m2), who were also trained. Insulin-glucose interactions were assessed by measuring indices of insulin sensitivity (SI) and glucose effectiveness at zero insulin (GEZI) using Bergman's minimal model. B-Cell function was assessed by determining the acute insulin responses (AIR) to glucose (AIRgluc) and arginine at 3 different glucose levels: fasting, approximately 14 mM, and greater than 28 mM (AIRmax). AIRmax provides a measure of B-cell secretory capacity, while the glucose level at which 50% of AIRmax occurs is termed PG50 and is used to estimate B-cell sensitivity to glucose. The insulin sensitivity and glucose effectiveness at zero insulin of the trained older subjects was similar to that of the trained young [SI: old, 5.1 +/- 0.6; young, 6.5 +/- 0.7 x 10(-5) min-1/pM (mean +/- SEM; P = NS); GEZI: old, 1.3 +/- 0.2; young, 1.7 +/- 0.2 x 10(-2) min (P = NS)]. Under these conditions, the fasting glucose levels (old, 5.4 +/- 0.2; young, 5.1 +/- 0.1 mM) and basal insulin levels (old, 49 +/- 6; young, 63 +/- 11 pM) were also similar in the two groups. AIRgluc values were lower in the exercised elderly (old, 253 +/- 50; young, 543 +/- 101 pM; P = 0.01). This decrease in stimulated insulin release was due solely to a reduction in the AIRmax (old, 1277 +/- 179; young, 2321 +/- 225 pM; P less than 0.005); the PG50 was not different (old, 8.9 +/- 0.4; young, 8.8 +/- 0.2 mM; P = NS). These differences in the older subjects were associated with a reduction in iv glucose tolerance (old, 1.49 +/- 0.15; young, 1.95 +/- 0.13%/min; P less than 0.05).(ABSTRACT TRUNCATED AT 400 WORDS)

Analysing the relationship between change in a risk factor and risk of disease

There are numerous examples in the epidemiologic literature of analyses that relate the change in a risk factor, such as serum cholesterol, to the risk of an adverse outcome, such as heart disease. Many of these analyses fit some type of regression model (such as logistic regression or the Cox model for survival time data) that includes both the change in the risk factor and the baseline value as covariates. We show that this method of adjusting for the baseline level can produce misleading results. The problem occurs when the true value of the risk factor relates to the outcome, and the measured value differs from the true value due to measurement error. We may find the observed change in the risk factor significantly related to the outcome when there is in fact no relationship between the true change and the outcome. If the question of interest is whether a person who lowers his level of the risk factor by means of drugs or lifestyle changes will thereby reduce his risk of disease, then we should consider an association due solely to measurement error as spurious. We present a method that adjusts for the measurement error in a linear regression analysis and show that an analogous adjustment applies asymptotically to logistic regression. As in other errors-in-variables problems, this analysis depends on knowledge of the relative variances of the random variation, the true baseline value, and the true change. Since the magnitudes of these variances are usually unknown and sometimes unknowable (the distinction between true change and measurement error being ambiguous), we recommend a sensitivity analysis that examines how the analysis results depend on the assumptions concerning the variances. The commonly used analysis method corresponds to the extreme case in which there is no measurement error. We use data from the Framingham Study and simulations to illustrate these points.

Physicians' attitudes toward tube feeding chronically ill nursing home patients

OBJECTIVE

To determine attitudes of physicians toward the limitation of tube feeding in chronically ill nursing home patients and the influences of patient preferences and other patient and physician variables on these decisions.

DESIGN

Questionnaire-based, mailed survey. Hypothetical case scenarios derived by fractional factorial design to determine the influences of patient and family preferences, age, life expectancy, physical and cognitive functioning; direct scaling to determine the influences of legal and cost considerations.

PARTICIPANTS

Randomly selected national samples of American Geriatrics Society and American Medical Association members (n = 141, participation rate 41%).

MAIN RESULTS

Nearly all physicians indicated they would withhold (95%) or withdraw (92%) tube feeding in at least one of the 16 scenarios studied. Physician decisions were most highly associated with patient preferences, followed by family preferences, life expectancy, and cognitive status (p less than 0.02 to less than 0.001). When patients and families agreed, physicians concurred in 87% to 95% of the decisions. However, when patients and families disagreed, physicians concurred with patients in only 48% to 55% of the decisions. Increasing physician concern regarding legal and cost considerations was significantly associated with significantly higher and lower likelihoods of tube feeding, respectively (p less than 0.05).

CONCLUSIONS

These results suggest that the majority of study physicians are willing to limit tube feeding in nursing home patients under some circumstances. Patient preferences appear to be the most important factor in these decisions, but may not be honored, especially if the wishes of patients and their families are not in concurrence.

The effect of intensive endurance exercise training on body fat distribution in young and older men

Little is known about the effects of exercise interventions on the distribution of central and/or intra-abdominal (IA) fat, and until now there were no studies in the elderly. Therefore, in this study we investigated the effects of an intensive 6-month endurance training program on overall body composition (hydrostatic weighing), fat distribution (body circumferences), and specific fat depots (computed tomography [CT]), in healthy young (n = 13; age, 28.2 +/- 2.4 years) and older (n = 15; age, 67.5 +/- 5.8 years) men. At baseline, overall body composition was similar in the two groups, except for a 9% smaller fat free mass in the older men (P less than .05). The thigh and arm circumferences were smaller (P = .001 and P less than .05, respectively), while the waist to hip ratio (WHR) was slightly greater in the older men (0.92 +/- 0.04 v 0.97 +/- 0.04, P less than .01). Compared with the relatively small baseline differences in body composition and circumferences, CT showed the older men to have a twofold greater IA fat depot (P less than .001), 48% less thigh subcutaneous (SC) fat (P less than .01), and 21% less thigh muscle mass (P less than .001). Following endurance (jog/bike) training, both the young (+18%, P less than .001) and the older men (+22%, P less than .001) significantly increased their maximal aerobic power (VO2max). This was associated with small but significant decrements in weight, percent body fat, and fat mass (all P less than .001) only in the older men.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of physical conditioning on fibrinolytic variables and fibrinogen in young and old healthy adults

BACKGROUND

The effects of 6 months of intensive endurance exercise training on resting tissue-type plasminogen activator (t-PA) activity, plasminogen activator inhibitor type 1 (PAI-1) activity, t-PA antigen, and fibrinogen were studied in 10 young (24-30 years) and in 13 old male subjects (60-82 years).

METHODS AND RESULTS

After training, maximum oxygen consumption was increased in the young group by 18% (44.9 +/- 5.0 to 52.9 +/- 6.6 ml/kg/min, p less than 0.001), whereas it was increased in the old group by 22% (29.0 +/- 4.2 to 35.5 +/- 3.6 ml/kg/min, p less than 0.001). The young group had no significant changes in any of the measured variables, whereas the old group had a 39% increase in t-PA activity (0.82 +/- 0.47 to 1.14 +/- 0.42 IU/ml, p less than 0.03), a 141% increase in the percentage of t-PA in the active form (11.1 +/- 7.7 to 26.8 +/- 15.1%, p less than 0.01), a 58% decrease in PAI-1 activity (8.4 +/- 4.9 to 3.5 +/- 1.7 AU/ml, p less than 0.01), and a 13% decrease in fibrinogen (3.57 +/- 0.79 to 3.11 +/- 0.52 g/l, p less than 0.01).

CONCLUSIONS

We conclude that intensive exercise training enhances resting t-PA activity and reduces fibrinogen and PAI-1 activity in older men. These effects are potential mechanisms by which habitual physical activity might reduce the risk of cardiovascular disease.

Body fat distribution in healthy young and older men

Central and/or intraabdominal (IA) fat is an independent predictor of obesity-related metabolic abnormalities in young and middle-aged subjects. The elderly are "fatter" at any given relative weight and often have similar metabolic abnormalities. In this study we compare body composition, circumferences, and specific fat depots areas in a population of healthy young and older men. Although the two groups were similar in body mass index and percent body fat, their distribution of adiposity was different. The young subjects had 16% and 10% larger thigh (p = .0001) and arm (p less than .01) circumferences respectively, while the ratio of waist-to-hip circumference was greater in the older subjects (0.93 +/- 0.04 vs 0.97 +/- 0.04, p = less than .01). The most striking differences between the groups were noted on computed tomography, with a twofold greater IA fat area (72.6 +/- 38.2 vs 143.6 +/- 56.2 cm2, p less than .0001), and a twofold lesser thigh subcutaneous fat area (156.3 +/- 69.3 vs 82.4 +/- 29.7 cm2, p less than .001) in the older subjects. We conclude there is an age-related central and intraabdominal redistribution of adipose mass, even in healthy older subjects. Since these changes occur in the absence of clinical disease, the associations between metabolic abnormalities and a central and or IA distribution of adiposity in the elderly must be investigated further.

Effect of exercise on insulin action, glucose tolerance, and insulin secretion in aging

To assess the effect of exercise training on the insulin resistance and impaired pancreatic B-cell function of aging, we studied 13 healthy older men (ages 61-82 yr) before and after 6 mo intensive endurance exercise. An index of insulin sensitivity (SI) was measured using Bergman's minimal model. Intravenous glucose tolerance was quantified using the glucose disappearance constant (KGlc) while oral glucose tolerance was assessed after a 100-g glucose load. B-cell function was evaluated by measuring the acute insulin response (AIR) to glucose injection at fasting glucose (AIRGlc) and the AIR to arginine at multiple clamped glucose levels. Exercise produced an endurance training effect as demonstrated by an 18% increase in maximum O2 consumption (VO2max) [38.2 +/- 1.4 to 45.0 +/- 1.1 (SE) ml.kg fat-free mass-1.min-1, P less than 0.001]. An unchanged fasting glucose (5.3 +/- 0.2 to 5.4 +/- 0.2 mM) despite a reduced fasting insulin (61 +/- 6 to 48 +/- 6 pM, P less than 0.01) suggested exercise training improved insulin sensitivity. This was confirmed by a 36% increase in SI from 3.47 +/- 0.41 to 4.71 +/- 0.42 x 10(-5) min-1/pM (P = 0.01). Intravenous glucose tolerance did not change as measured by KGlc, which was 1.46 +/- 0.09 before and 1.48 +/- 0.16%/min after exercise training. Likewise, the incremental glucose response to oral glucose (633 +/- 49-618 +/- 45 mM.min) was unchanged. B-cell function was decreased as reflected by AIRGlc (351 +/- 73-245 +/- 53 pM, P less than 0.01) and the AIRArg at maximal glycemic potentiation (AIRmax, 1,718 +/- 260-1,228 +/- 191 pM, P less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Understanding of elderly patients' resuscitation preferences by physicians and nurses

We compared the understanding by family physicians and nurses of their elderly outpatients' preferences for cardiopulmonary resuscitation and mechanical ventilation under 3 scenarios reflecting varying qualities of life. Physicians and nurses correctly predicted patients' treatment preferences in from 59% to 84% and 53% to 78% of cases, respectively, for the various decisions. For most decisions, neither physicians nor nurses were significantly more accurate in their predictions than expected by chance alone. Moreover, nurses and physicians did not significantly agree with one another in their predictions of patients' preferences for any of these decisions. These results suggest that while nurses' and physicians' perceptions of patients' preferences for life-sustaining treatment are not necessarily similar, neither nurses nor physicians systematically understand their elderly patients' resuscitation preferences.

Physicians' and spouses' predictions of elderly patients' resuscitation preferences

"Substituted judgment," in which surrogate decisionmakers approximate patients' wishes, has been recommended for decision making for mentally incapacitated patients. To test understanding of patients' preferences by potential surrogate decisionmakers, we studied primary care physicians' (n = 105) and spouses' (n = 90) predictions of elderly outpatients' (n = 258) preferences for cardiopulmonary resuscitation (CPR) and CPR plus ventilator (CPR + V), assuming three baseline health states: current health, stroke, and chronic lung disease. Although more than three-quarters of physicians and spouses surveyed believed their predictions of patients' preferences were accurate, the accuracy of physicians' and spouses' predictions did not exceed that expected due to chance alone in 5 of 6, and 3 of 6 decisions, respectively. Physicians significantly underestimated patients' preferences for resuscitation in the stroke and chronic lung disease scenarios (p less than .01), and significantly overestimated them in the current health/CPR decision (p less than .05). Spouses overestimated patients' preferences for resuscitation in all decisions, significantly so in the three CPR + V decisions (p less than .05). These results suggest physicians and spouses often do not understand elderly outpatients' resuscitation preferences. Under these circumstances they are unlikely to provide accurate substituted judgments.

Optimal detection of the progression of coronary artery disease: comparison of methods suitable for risk factor intervention trials

To assess the best method of quantitating progression of coronary disease, we studied four measurements in 114 coronary segments from 35 medically treated patients from whom angiograms were obtained 5 years apart. Only stenoses of less than 70% that were visualized in nearly identical projections on both angiograms were evaluated. Vessel edges were measured by use of catheter calibration and an automated computer algorithm yielding two "absolute dimensions" (mean and minimum diameters) and two measurements (percent stenosis and atheroma area) that required a "normal reference" diameter. The coefficient of variation for repeated segment measurements was less for mean and minimum diameter than for percent stenosis and area of atheroma. The best measure of progression of coronary disease as determined by t test comparison of different methods was the change in mean diameter over time (6.7 +/- 14.1% decrease), whether calculated on a per coronary segment or per patient basis (p less than .001). Based on this measurement and its standard deviation of progression of coronary disease in this patient subset with relatively benign disease, it is estimated that 470 patients per group would be required for an interventional study to demonstrate a 33% reduction in disease progression (207 patients for 50% reduction) at a 95% confidence level and 90% power.

The significance of bone marrow involvement in non-Hodgkin's lymphoma: the Eastern Cooperative Oncology Group experience

Data from four clinical trials conducted by the Eastern Cooperative Oncology Group (ECOG) were used to investigate the importance of bone marrow involvement as a prognostic factor in patients with non-Hodgkin's lymphoma (NHL). A total of 502 patients, 275 with nodular, poorly differentiated lymphocytic lymphoma (NLPD) and 227 with diffuse histiocytic lymphoma (DHL) or diffuse mixed-cell lymphoma (DML), were included in this analysis. Patients were separated into four categories: stage III, stage IV with bone marrow involvement (stage IV-M), stage IV without marrow involvement (stage IV-O), and stage IV with bone marrow and other organ involvement (stage IV-OM). Among the DHL and DML patients, the incidence of marrow involvement was 23%. However, stage IV-M patients had a prognosis that is similar to stage IV-O and stage IV-OM and worse than stage III patients. In contrast, the incidence of involvement with NLPD was 59% and patients with stage IV-M had a survival not different than stage III and not worse than stage IV-O and stage IV-OM. The results suggest that the current emphasis on bone marrow biopsy(s) as a routine diagnostic staging procedure for patients with NHL should be reevaluated. The necessity for this procedure in stage III patients with NLPD is not apparent from our data. One can still justify a bone marrow biopsy in stage I and II patients and can confirm the complete clinical response when all nodes have regressed in more advanced disease.

The superiority of sequential over simultaneous testing

Diagnostic tests are typically used to help the physician select among available management options. When two or more tests are available, using them sequentially is potentially more efficient than simultaneously performing multiple tests, in that the former approach may allow the physician to perform fewer tests. In particular, we demonstrate that if two common conditions are met, any simultaneous strategy involving at least as many tests as management options can be replaced by a sequential strategy with the same outcome and a smaller expected number of tests. It follows that, in many clinical situations in which the benefits of performing fewer tests outweigh the costs that may result from delaying diagnosis, simultaneous strategies cannot be optimal. This result can decrease the number of diagnostic strategies that the physician or decision analyst needs to consider.

Charts for the early stopping of pilot studies

Cooperative oncology groups usually run pilot studies of new agents or combinations concurrently with their major randomized clinical trials. A primary objective of these studies is to determine whether the new regimen should be tested further in a group-wide clinical trial. The accrual goals of such pilot studies are typically fixed in advance at between 30 and 40 patients, on the grounds that this number provides a reasonably tight confidence interval on the true response rate. Nevertheless early termination of pilot studies is often desirable either because the regimen appears inactive or because early results indicate extreme activity and justify immediate testing in a randomized study. Statistical charts are provided for early termination in both these situations. The charts are read by specifying the number of evaluable patients already accrued, the number of responses observed and the minimum true response rate, theta 0, at which the regimen would be considered active. The charts provide the posterior probability that the true response rate exceeds theta 0, that is, that the regimen is active. An additional chart that computes a 90% probability interval for the true response rate, based on the observed rate and sample size, is also provided. The use of the chart is illustrated with two examples from the Eastern Cooperative Oncology Group.

Approximate case influence for the proportional hazards regression model with censored data

A method is presented for approximating the influence of individual cases upon regression coefficient estimates obtained from the Cox proportional hazards model. Observations can thus be identified which may greatly influence statistical inferences regarding the effects of prognostic factors upon survival time. An example from a cancer clinical trial is given.