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Biomedical subjects

Nancy E Mayo

Publications and source records attributed to Nancy E Mayo.

At least 19 recordsLinked to original sources
PubMed2006

Arterial versus capillary blood gases: a meta-analysis.

A meta-analysis determined whether capillary blood gases accurately reflect arterial blood samples. A mixed effects model was used on 29 relevant studies obtained from a PubMed/Medline search. From 664 and 222 paired samples obtained from the earlobe and fingertip, respectively, earlobe compared to fingertip sampling shows that the standard deviation of the difference is about 2.5x less (or the precision is 2.5x better) in resembling arterial PO(2) over a wide range of arterial PO(2)'s (21-155 mm Hg ). The lower the arterial PO(2), the more accurate it is when predicting arterial PO(2) from any capillary sample (p<0.05). However, while earlobe sampling predicts arterial PO(2) (adjusted r(2)=0.88, mean bias=3.8 mm Hg compared to arterial), fingertip sampling does not (adjusted r(2)=0.48, mean bias=11.5 mm Hg compared to arterial). Earlobe sampling is slightly more accurate compared to fingertip sampling in resembling arterial PCO(2) (arterial versus earlobe, adjusted r(2)=0.94, mean bias=1.9 mm Hg ; arterial versus fingertip, adjusted r(2)=0.95, mean bias=2.2 mm Hg compared to arterial) but both sites can closely reflect arterial PCO(2) (880 total paired samples, range 10-114 mm Hg ). No real difference between sampling from the earlobe or fingertip were found for pH as both sites accurately reflect arterial pH over a wide range of pH (587 total paired samples, range 6.77-7.74, adjusted r(2)=0.90-0.94, mean bias=0.02). In conclusion, sampling blood from the fingertip or earlobe (preferably) accurately reflects arterial PCO(2) and pH over a wide range of values. Sampling blood, too, from earlobe (but never the fingertip) may be appropriate as a replacement for arterial PO(2), unless precision is required as the residual standard error is 6 mm Hg when predicting arterial PO(2) from an earlobe capillary sample.

Arteries↗
PubMed2006

Peering at peer review revealed high degree of chance associated with funding of grant applications.

BACKGROUND AND OBJECTIVES: There is a persistent degree of uncertainty and dissatisfaction with the peer review process underlining the need to validate the current grant awarding procedures. This study compared the CLassic Structured Scientific In-depth two reviewer critique (CLASSIC) with an all panel members' independent ranking method (RANKING). Eleven reviewers, reviewed 32 applications for a pilot project competition at a major university medical center. RESULTS: The degree of agreement between the two methods was poor (kappa = 0.36). The top rated project in each stream would have failed the funding cutoff with a frequency of 9 and 35%, depending on which pair of reviewers had been selected. Four of the top 10 projects identified by RANKING had a greater than 50% of not being funded by the CLASSIC ranking. Ten reviewers provided optimal consistency for the RANKING method. CONCLUSIONS: This study found that there is a considerable amount of chance associated with funding decisions under the traditional method of assigning the grant to two main reviewers. We recommend using the all reviewer ranking procedure to arrive at decisions about grant applications as this removes the impact of extreme reviews.

Canada↗
PubMed2006

Identification in administrative databases of women dying of breast cancer.

PURPOSE: Palliative care is an essential component of cancer care, and population-based research is needed to monitor its impact. Administrative databases are the cornerstone of health services research. Their limitation is that cause of death is not sufficient to readily classify decedents as terminally ill for the study of the health services they received at the end of life. The study purpose is to develop and test the validity of an algorithm allowing the classification of the decedents as dying of breast cancer (BC), using administrative data. METHODS: Validation was carried out through a chart review of 119 BC decedents extracted from hospital-based databases. This algorithm was applied to 3,384 deceased women with BC representative of the whole population. The effect of the classification by the algorithm was illustrated by the shift in the distributions of age and place of death. RESULTS: The validation showed a sensitivity of 95%, a specificity of 89%, a positive predictive value of 98%, and negative predictive value of 77% for the classification of women dying of BC. Of the 3,384 decedents, 2,293 were classified as dying of, and 1,091 as not dying of BC. Women dying of BC were younger, died less often at home (6.9% v 17.9%), and in chronic care institutions (4.1% v 14.8%), and more often in acute-care beds (69.9% v 57.1%). CONCLUSION: This novel way to classify decedents is conceptually based and empirically validated through chart review and impact on distribution of age and place of death.

Adult↗
PubMed2006

Balance self-efficacy and its relevance to physical function and perceived health status after stroke.

OBJECTIVES: To estimate the level of balance self-efficacy among community-dwelling subjects with stroke and to determine the relative importance of balance self-efficacy compared with functional walking capacity in predicting physical function and perceived health status. DESIGN: Secondary analysis of baseline, postintervention, and 6-month follow-up data from a randomized trial. SETTING: General community. PARTICIPANTS: Ninety-one subjects with a first or recurrent stroke, discharged from rehabilitation therapy with a residual walking deficit. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The Activities-Specific Balance Confidence (ABC) Scale, Medical Outcomes Study 36-Item Short-Form Health Survey physical function scale, and the EQ-5D visual analog scale of perceived health status. RESULTS: Average balance self-efficacy was 59 out of 100 points on the ABC scale (95% confidence interval, 55-64; n=89). After adjusting for age and sex, functional walking capacity explained 32% and 0% of the respective variability in physical function and perceived health status scores obtained 6 months later. After adjustment for age, sex, and functional walking capacity, balance self-efficacy explained 3% and 19% of variation in 6-month physical function and perceived health status scores, respectively. CONCLUSIONS: Subjects living in the community after stroke experience impaired balance self-efficacy. Enhancing balance self-efficacy in addition to functional walking capacity may lead to greater improvement, primarily in perceived health status, but also in physical function, than the enhancement of functional walking capacity alone.

Activities of Daily Living↗
PubMed2006

Development of a position-specific index of muscle strength to be used in stroke evaluation.

OBJECTIVE: To develop a position-specific index of muscle strength for individuals with stroke. DESIGN: Cross-sectional design. SETTING: A major teaching hospital in a Canadian urban city. PARTICIPANTS: Sixty-three patients with poststroke onset between 3 and 12 months. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: The muscle strength of the lower-extremity muscles was tested bilaterally in multiple positions using hand-held dynamometry. RESULTS: A principal components analysis resulted in grouping the muscles of the affected and unaffected sides of the gravity related and gravity eliminated positions into 5 indices. The 5 indices were moderately to highly correlated (r2 range, .59-.81) with each other and so were combined into 1 global index. The gravity related muscle strength on the affected side was, on average, 85% of the unaffected side (range, 37%-157%); the gravity eliminated muscle strength of the affected side was, on average, 92% of the unaffected side (range, 53%-121%). CONCLUSIONS: This study resolves the methodologic issue of how to summarize multiple data points that relate to one construct, namely, strength of different muscle groups assessed in several positions.

Aged↗
PubMed2006

Psychometric evaluation of the original and Canadian French version of the activities-specific balance confidence scale among people with stroke.

OBJECTIVE: To evaluate the internal and absolute reliability and construct validity of the Activities-Specific Balance Confidence (ABC) scale and a new Canadian French version (ABC-CF) of it among people with stroke. DESIGN: Cross-sectional data from a randomized controlled trial. SETTING: Community. PARTICIPANTS: Ninety-one people with a residual walking deficit between 57 and 386 days poststroke. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The ABC and ABC-CF scales, Berg Balance Scale (BBS), comfortable and maximum gait speeds, Timed Up & Go (TUG) test, 6-minute walk test (6MWT), Barthel Index, physical function scale of the Medical Outcomes Study 36-Item Short-Form Health Survey, Geriatric Depression Scale (GDS), and the EQ-5D visual analog scale (EQ VAS). RESULTS: Internal consistency (Cronbach alpha) was .94 and .93 and the standard error of measurement was 5.05 and 5.13 for the ABC (n=51) and the ABC-CF (n=35) scales, respectively. Spearman rho values ranged from .30 to .60 for the ABC scale and from .45 to .68 on the ABC-CF scale for associations with scores on the BBS, comfortable and maximum gait speeds, TUG, 6MWT, Barthel Index, physical function scale, GDS, and EQ VAS. CONCLUSIONS: Evidence of internal and absolute reliability and of construct validity of the ABC and the ABC-CF scales supports their use for cross-sectional measurements of balance self-efficacy among community-dwelling people in the first year poststroke.

Adult↗
PubMed2006

Ranking hospitals according to acute myocardial infarction mortality: should transfers be included?

OBJECTIVE: The objective of this population-based observational cohort study was to estimate the extent to which the inclusion/exclusion of transferred patients with acute myocardial infarction (AMI) impacts on hospital performance rankings. SUBJECTS: The authors studied 91,633 adult patients admitted to 116 acute care hospitals in Quebec, Canada, with a primary diagnosis of AMI between 1992 and 1999. MAIN OUTCOME MEASURE: Hospital performance ranks, based on 30-day AMI mortality rates, were estimated with hierarchical models and compared using 3 different methods for handling transferred patients (exclude all transfers; include transfers and assign outcome to the referring hospital; include transfers and assign outcome to the receiving hospital). The explanatory variable of interest was the hospital to which the patient's outcome was attributed. RESULTS: Using the 3 methods, 4 hospitals were ranked "best performers" once, and 1 hospital ranked among the best in 2 of the 3 analyses performed. Nine hospitals were ranked "worst performers" at least once (4 of which ranked among the "worst" once only, 2 ranked among the "worst" twice, and 3 were consistently ranked "worst performers" in all analyses). There was significant variation in mortality rates among hospitals, and the difference in the rates between the highest and lowest ranking hospitals exceeded the clinically relevant benchmark of 1%. CONCLUSIONS: Performance evaluation studies that compare hospital mortality rates typically exclude transferred patients. However, methods used to deal with AMI patient transfers influenced hospital ranks when comparing 30-day mortality rates. Excluding transfers may lead to an inaccurate depiction of the quality of healthcare services in regionalized healthcare systems that call for the timely interhospital transfer of patients with AMI.

Aged↗
PubMed2006

The effect of a task-oriented intervention on arm function in people with stroke: a randomized controlled trial.

OBJECTIVE: To evaluate the efficacy of a task-oriented intervention in enhancing arm function in people with stroke. DESIGN: Two-centre, observer-blinded, stratified, block-randomized controlled trial. SETTING: General community. PATIENTS: Ninety-one individuals within one year of a first or recurrent stroke consented to participate between May 2000 and February 2003. INTERVENTIONS: The experimental intervention involved practice of functional, unilateral and bilateral tasks that were designed to improve gross and fine manual dexterity whereas the control intervention was composed of walking tasks. Members in both groups participated in three sessions a week for six weeks. MAIN OUTCOME MEASURE(S): The primary test of arm function was the Box and Block Test. Secondary tests included the Nine-Hole Peg Test, maximal grip strength, the Test d'Evaluation des Membres supérieurs des Personnes Agées (TEMPA) and the Stroke Rehabilitation Assessment of Movement. RESULTS: Results are for the more affected arm. Baseline performance on the Box and Block Test was an average of 26 blocks (standard deviation (SD) = 16) in the experimental group (n = 47) and 26 blocks (SD = 18) in the control group (n = 44). These values represent approximately 40% of age-predicted values. Values for the postintervention evaluation were an average of 28 (SD = 17) and 28 (SD = 19) blocks for the experimental and control group respectively. No meaningful change on other measures of arm function was observed. CONCLUSIONS: A task-oriented intervention did not improve voluntary movement or manual dexterity of the affected arm in people with chronic stroke.

Activities of Daily Living↗
PubMed2005

The structural equation modeling technique did not show a response shift, contrary to the results of the then test and the individualized approaches.

BACKGROUND AND OBJECTIVE: Persons experiencing changes in their physical health may change their values and rerate the importance of basic elements of health-related quality of life (HRQL), a process known as response shift. Developing an estimator of HRQL that differentiates between objective change and response shift is essential for the interpretation of the results. The purpose of the present article was to contrast three methodologic approaches for evaluating response shift to develop a proposed set of HRQL measurement recommendations under circumstances where response shift is expected to occur. METHODS: The three approaches compared were a structural equation modeling (SEM) technique, the then test, and an individualized approach. The data collection procedures for these methods were incorporated into a poststroke randomized controlled trial. RESULTS: The SEM did not show a response shift, contrary to the results of the then test and the individualized approaches. We discuss factors that effect the selection of a methodologic approach including feasibility, subjects' memory and more advanced cognitive tasks, and whether response shift was evaluated at the group or individual level. CONCLUSION: The evaluation of response shift is an integral part of HRQL evaluations, and further comparisons between methodologic approaches are needed.

Activities of Daily Living↗
PubMed2005

Change in quality of life of people with stroke over time: true change or response shift?

UNLABELLED: In many studies, assessments of change in self-report measures such as health-related quality of life must account for potential response shift, including reconceptualization and changes in internal standards of measurement. OBJECTIVE: The objective of our study was to compare healthy controls and individuals with stroke on the extent to which changes in internal standards and reconceptualization of health related quality of life (HRQL) occurs over the first 6 months post-stroke. METHODS: Confirmatory factor analysis was used to assess invariance of the SF-36 measurement model over time among 238 individuals with stroke and 392 controls, separately. This procedure assessed changes over time in the factor loadings, variances, and covariances of responses, and compared the extent of change between individuals with stroke and those in the control group. In addition a multisample comparison was made between individuals with stroke and members of the control group at the first evaluation in order to assess invariance of the SF-36 measurement model between the groups. The controls were considered to be a 'proxy' for the stroke cohort prior to the stroke. RESULTS: We found no evidence of reconceptualization and changes in internal standards over time when the groups were assessed separately. There was a significant difference in the factor covariances (reconceptualization) between the two groups at the time of the first evaluation. However, measurement error was also significant for this comparison. CONCLUSION: This study indicates that the improvement in HRQL over time is real rather than a result of reconceptualization or a recalibration. If response shift does occur with stroke it is likely to be mediated by the event itself and not the recovery process.

Activities of Daily Living↗
PubMed2005

Using the Patient Generated Index to evaluate response shift post-stroke.

BACKGROUND: Individualized measures allow for the assessment of health-related quality of life (HRQL) based on areas that are relevant to the person and may prove to be useful for evaluating response shift (reconceptualization of HRQL and change in values). OBJECTIVE: The objective of this study was to assess reconceptualization of HRQL and change of individual values among persons with stroke during the first six months of recovery. METHODS: The data collection for this study was incorporated into a randomized trial of acute post-stroke care. Individualized HRQL was evaluated at 6 and 24 weeks post-stroke using the Patient Generated Index (PGI). At 24 weeks a semi-structured interview was administered to assess whether verbalizations given by subjects indicated that they had experienced a response shift. RESULTS: Ninety two subjects (61%) had complete PGI information at the 6- and 24-week evaluations, and of these, 46 completed the semi-structured interview. Between the 6- and 24-week evaluations, the domains selected were: the same for 10 (11%) subjects, reduced for 27 (29%), expanded for 11 (12%), and completely different for 44 (48%) subjects. Twenty eight percent (n = 13) of subjects recovering from stroke experienced a response shift as evidenced by the semi-structured interviews. CONCLUSION: The PGI provides valuable information regarding changes in person's conceptualization of HRQL and values, but the feasibility of using an individualized measure during the first six months post-stroke is limited by the added complexity of completing and interpreting such a measure.

Aged↗
PubMed2005

Does the addition of functional status indicators to case-mix adjustment indices improve prediction of hospitalization, institutionalization, and death in the elderly?

BACKGROUND: Case-mix adjustment is widely used in health services research to ensure that groups being compared are equivalent on variables predicting outcome. There has been considerable development and testing of comorbidity indices derived from diagnostic codes recorded in administrative databases, but increasingly, the benefit of clinical information and patient reported ratings of health and functional status is being recognized. One type of information that is highly valued but has so far not been captured by administrative health databases is functional status indicators (FSI). OBJECTIVE: The purpose of this study was to estimate the extent to which prediction of health outcomes can be improved on by including information on functional status indicators (FSI). RESEARCH DESIGN: The data for the current study was obtained from a clustered randomized trial evaluating computerized decision support for managing drug therapy in the elderly, conducted from 1997 to 1998. A total of 107 primary care physicians participated in this trial and 6465 of their patients (51%) completed a generic health status measure-the SF-12-before the intervention. C statistics and R were used to compare the predictive value of sociodemographic factors, 2 comorbidity indices, and 11 FSI predictor variables derived from the SF-12 and coded (possible for 8) using the International Classification of Functioning (ICF). RESULTS: Using stepwise logistic regression, FSI, particularly limitation in stair climbing or doing moderate activities like housework, were found to be strong and independent predictors of all outcomes, even after controlling for sociodemographics and comorbidity. CONCLUSION: This study indicates that FSI provided as robust a prediction of health events as did complex comorbidity indices. Additionally, the ICF coding system provides a mechanism whereby information on FSI could be incorporated into administrative databases through the use of electronic health records that include a health or functional status measure.

Activities of Daily Living↗
PubMed2005

The effect of a task-oriented walking intervention on improving balance self-efficacy poststroke: a randomized, controlled trial.

OBJECTIVES: To evaluate the efficacy of a task-oriented walking intervention in improving balance self-efficacy in persons with stroke and to determine whether effects were task-specific, influenced by baseline level of self-efficacy and associated with changes in walking and balance capacity. DESIGN: Secondary analysis of a two-center, observer-blinded, randomized, controlled trial. SETTING: General community. PARTICIPANTS: Ninety-one individuals with a residual walking deficit within 1 year of a first or recurrent stroke. INTERVENTION: Task-oriented interventions targeting walking or upper extremity (UE) function were provided three times a week for 6 weeks. MEASUREMENTS: Activities-specific Balance Confidence Scale, Six-Minute Walk Test, 5-m walk, Berg Balance Scale, and Timed "Up and Go" administered at baseline and postintervention. RESULTS: The walking intervention was associated with a significantly greater average proportional change in balance self-efficacy than the UE intervention. Treatment effects were largest in persons with low self-efficacy at baseline and for activities relating to tasks practiced. In the walking group, change in balance self-efficacy correlated with change in functional walking capacity (correlation coefficient=0.45, 95% confidence interval=0.16-0.68). Results of multivariable modeling suggested effect modification by the baseline level of depressive symptoms and a prognostic influence of age, sex, comorbidity, time poststroke, and functional mobility on change in self-efficacy. CONCLUSION: Task-oriented walking retraining enhances balance self-efficacy in community-dwelling individuals with chronic stroke. Benefits may be partially the result of improvement in walking capacity. The influence of baseline level of self-efficacy, depressive symptoms, and prognostic variables on treatment effects are of clinical importance and must be verified in future studies.

Adult↗
PubMed2005

Measuring surgical recovery: the study of laparoscopic live donor nephrectomy.

Following laparoscopic donor nephrectomy (LDN), recovery has only been studied using traditional outcomes, subjective and confounded by comorbidity and psychosocial variables. The purpose of this study is to estimate surgical recovery following LDN using standardized, validated instruments and to compare this recovery profile to that obtained with traditional measures. This was a prospective study of patients undergoing LDN at a single institution between September 2001 and January 2004 (n = 35). At baseline and 4 weeks following surgery, functional exercise capacity was measured using the 6-min walk test (6MWT) and health-related quality of life was assessed with the Short Form-36 (SF-36) questionnaire, including physical component summary (PCS) and mental component summary (MCS) scores. Patients' self-assessment of recovery and time to resumption of regular activities was ascertained. At follow-up (median 29 days), patients' 6MWT was lower by a median of 30 m (p = 0.07) and PCS decreased from 57.1 to 42.3 (p = 0.0001), whereas MCS remained constant. Overall, length of stay, return to activities and patient-stated recovery were inadequate outcomes for classifying patient recovery using 6MWT and PCS as the reference standards. Four weeks following LLDN, patients have returned to baseline exercise capacity, but not baseline general physical health. Traditional measures of recovery are incomplete descriptors of recovery.

Adult↗
PubMed2005

On the significance of reducing the need for stroke patients to visit the emergency department.

We studied the care-provider paths followed by 3,946 patients in Quebec in 2001. We showed that the patients flow during the three months preceding discharge from hospital can be represented by a Markov model with memory. This model enables study of four major scenarios to improve health outcomes, workloads and cost efficiency in the overall community-based care delivery system. Based on the field data, we establish that increasing the availability of specialists, family physicians and general practitioners to mitigate the need for ER visits would be an effective strategy for improvement. A comprehensive policy to support stroke patients needs to incorporate both hospital-based and community-based care delivery processes. The seamless flow of patients through the healthcare providers in such an integrated system is crucial for achieving successful outcomes. Emergency rooms (ER) have a crucial role in this context, since in many cases ER acts as the hospital's "gate keeper", determining if a patient needs to be (re)admitted. In this paper, we establish (based on field data) that mitigating the ER visits of stroke patients improves health outcomes, distribution of workload across the healthcare system as well as associated costs. To this end, we make use of a Markov modeling framework, where the aggregate patient flow information is represented in a compact form through the use of a transition-probability matrix. This allows us to investigate the system-wide impact of several plausible scenarios with regards to the delivery of community-based care to stroke patients who are recently discharged from hospital.

Community Health Centers↗
PubMed2004

Incorporating the International Classification of Functioning, Disability, and Health (ICF) into an electronic health record to create indicators of function: proof of concept using the SF-12.

OBJECTIVE: The purpose of this proof-of-concept study was to assess the feasibility of using a generic health measure to create coded functional status indicators and compare the characterization of a stroke population using coded functional indicators and using health-related quality-of-life summary measures alone. DESIGN: Multiple raters assigned International Classification of Functioning, Disability, and Health (ICF) codes to the items of the 12-Item Short Form Health Survey (SF-12). Data for comparing the information from the SF-12 and from ICF codes were derived from the Montreal Stroke Cohort Study that was set up to examine the long-term impact of stroke. Available for analysis were data from 604 persons with stroke, average age 69 years, and 488 controls, average age 62 years. MEASUREMENT: The SF-12 provides two summary scores, one for physical health and one for mental health. Domains of the ICF are coded to three digits, before the decimal; specific categorizations of impairments, activity limitations, and participation restrictions are coded to four digits before the decimal. RESULTS: Persons with stroke scored, on average, approximately 10 points lower than controls on physical and mental health. The ICF coding indicated that this was attributed, not surprisingly, to greater difficulty in doing moderate activities including housework, climbing stairs, and working and was not attributed to differences in pain. Differences in mental health were attributed most strongly to greater fatigue (impairment in energy), but all areas of mental health were affected to some degree. CONCLUSION: The ICF coding provided enhanced functional status information in a format compatible with the structure of administrative health databases.

Activities of Daily Living↗
PubMed2004

Pattern of care at the end of life: does age make a difference in what happens to women with breast cancer?

PURPOSE: In the last 40 years, palliative care has become the standard of care at the end of life. However, there are limited data about the degree of access to such care at the population level. METHODS: Using administrative databases, a care-oriented profile score was created to describe the care received during the last 6 months of life for 2,291 women who were dying of breast cancer in the province of Quebec, Canada, during the years 1992 to 1998. The care received was described through indicators of care that would reflect a palliative care philosophy. An ordinal score was developed for comparisons among age groups of women using a proportional odds ordinal regression model. RESULTS: We found that only 6.9% of women died at home, while 69.6% of them died in acute care beds. While most women (75%) had few indicators indicating provision of palliative care during the last 6 months of life, younger women (< 50 years) were even less likely (odds ratio, 0.70; 95% CI, 0.54 to 0.90) to receive such care compared with middle aged women (50 to 59 years; serving as the reference group), while older women (> 70 years) were more likely (odds ratio, 1.85; 95% CI, 1.49 to 2.29). CONCLUSION: Our study indicates that a sizeable proportion of women terminally ill from breast cancer do not have access to palliative care-an issue that health care policy makers may wish to explore further.

Age Factors↗