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PubMedDate not supplied

Canada: agreement between patient and proxy information about colorectal cancer therapies.

Proxies, such as next of kin, often provide information to healthcare professionals about a cancer patient they know, particularly when this information is not available from the patient. Understanding the extent to which proxies offer reliable information about patients is important for improving the quality of patient care and also for assessing the quality of research, evaluation, and administrative data when proxy response is utilized. This study determined Levels of agreement between information reported by colorectal cancer patients and by their proxies about complementary and alternative medicine obtained by questionnaire response. Patient-proxy agreement was also compared for conventional therapies, patient demographics, lifestyle, and symptoms.

Adult↗
PubMed2003

Further evidence for the agreement between patients with stroke and their proxies on the Frenchay Activities Index.

OBJECTIVE: To determine item, subscale and total score agreement on the Frenchay Activities Index (FAI) between stroke patients and proxies six months after discharge from rehabilitation. DESIGN: Prospective study design. SETTING/SUBJECTS: Fifty patient-proxy pairs, interviewed separately, in the patient's residence. MAIN OUTCOME MEASURES: Modified FAI using 13 items. Individual FAI items, subscales and total score agreement as measured by weighted kappa and intraclass correlation coefficients (ICC). RESULTS: Excellent agreement was found for the total FAI (ICC 0.87, 95% confidence interval (CI) 0.78-0.93), and domestic (ICC 0.85, 95% CI 0.73-0.91) and outdoor (ICC 0.87, 95% CI 0.78-0.95) subscales, with moderate agreement found for the work/leisure subscale (ICC 0.63, 95% CI 0.34-0.78). For the individual FAI items, good, moderate, fair and poor agreement was found for five, three, four and one item, respectively. The best agreement was for objective items of preparing meals, washing-up, washing clothes, shopping and driving. The poorest agreement was for participation in hobbies, social outings and heavy housework. Scoring biases associated with patient or proxy demographic characteristics were found. Female proxies, and those who were spouses, scored patients lower on domestic activities; male patients, and those who were younger, scored themselves higher on outdoor activities and higher patient FIM scores were positively correlated with higher FAI scores. CONCLUSIONS: While total and subscale agreement on the FAI was high, individual item agreement varied. Proxy scores should be used with caution due to bias.

Activities of Daily Living↗
PubMed2005

The safety of patient-controlled analgesia by proxy in pediatric oncology patients.

Between February 1999 and December 2003, we studied the use of patient-controlled analgesia (PCA) to control pain in 1011 children and young adults with cancer, by evaluating 4972 24-h periods of PCA usage, 576 of which involved PCA by proxy. Selection of patients for PCA by proxy was based on younger age group, neuromuscular limitation, expectation of repeated painful procedures, and terminal disease. We measured the incidence of respiratory and neurological complications related to the use of PCA. Major complications were observed during 70 of the 4972 24-h observations, with 28 of 4972, or 0.56%, involving respiratory complications, 35 of 4972, or 0.7%, involving neurological complications, and 7 of 4972 24-h observations, or 0.14%, involving both respiratory and neurological complications. In the PCA by proxy group two respiratory complications, two neurological complications and one mixed respiratory and neurological complication were observed [corrected] Reversal of opioid-related respiratory or neurological effects with naloxone was required in three instances, two in the standard PCA group and one in the PCA by proxy group. Recommendations to ensure continuing safety include careful patient selection, education of proxy users, appropriate documentation, and institutional guidelines.

Adolescent↗
PubMed2005

Children's physical activity: using accelerometers to validate a parent proxy record.

INTRODUCTION: The purpose of this study was to validate a parent proxy record of children's physical activity with CSA Model 7164 accelerometers. METHODS: A parent proxy record was developed to record children's activity after school on weekdays and all day long on weekends for 7 d. Parents recorded both duration and intensity of activity (light, medium, hard and very hard). Children simultaneously wore a CSA-7164 accelerometer around their right hip, which served as the objective measurement against which the proxy record was validated. Sixty-five parent/child dyads participated in the study. RESULTS: The overall activity level of the children was low (<3 METs). Spearman-rho analyses indicated that the accelerometer and proxy record showed poor to fair agreement for the entire monitoring period, with parents consistently overreporting their child's activity levels. Correlation between the two instruments was highest at midday on weekends (0.383) and immediately after school on weekdays (0.267). CONCLUSION: Due to the low correlation between this proxy record and the accelerometer, the need still exists for a valid measurement of child physical activity that is both inexpensive and easy to employ in larger community-based interventions.

Child↗
PubMed2006

Capacity issues related to the health care proxy.

The concept of capacity, its ethical mandates, and a rationale for the assessment of capacity to execute a health care proxy was discussed. Special New York State regulations, relevant to the execution of a health care proxy by persons who have mental retardation, were reviewed, discussed, and compared with regulations in some other jurisdictions. Technical information about a health care proxy and the appropriate form for a simple health care proxy were described. A standard for psychologists and physicians to use in assessing the capacity of a person with cognitive impairments to execute a health care proxy is presented.

Health Services↗
PubMed2000

[Validity of occupational histories from proxy respondents].

OBJECTIVE: Occupational studies often use data obtained from proxy respondents. However, few investigations have been conducted on the validity of occupational data provided by workers' surrogates. This study aimed to compare self-reported occupational data to information obtained from next-of-kin, as a contribution to assess the validity of using proxy respondents to obtain information about workers. METHODS: Worker/next-of-kin pairs, residents in Southeastern Brazil, were interviewed separately in 1998 about worker's occupational past history. The concordance, sensitivity, and specificity of proxy reports about workers' occupations were examined comparing to self-reports. RESULTS: A total of 2.163 worker/next-of-kin pairs were interviewed. The Kappa statistic for the agreement between worker's and next-of-kin's report about the worker's main occupation was 0.86 (CI95%; 0.85 - 0.88). The sensitivity of proxy reports on occupations ranged from 77.5% (64.6% - 90.4%) to 98.9% (97.3% - 100.0%), and specificity ranged from 96. 9% (96.0% - 97.7%) to 99.9% (99.7% - 100.0%). CONCLUSIONS: These are encouraging findings for the use of proxy respondents in occupational studies when occupations are considered as categorical variables. However, caution is required when assessing occupational exposition by means of cumulative work time because next-of-kin may underestimates this information.

Adolescent↗
PubMed2004

Proxy reporting of health information.

OBJECTIVES: This article documents the extent of proxy reporting in Statistics Canada's National Population Health Survey (NPHS) and explores associations between reporting status and the prevalence and incidence of selected health problems. DATA SOURCES: Data are from the household cross-sectional (1994/95, 1996/97 and 1998/99) and longitudinal (1994/95 to 2000/01) components of the NPHS. Supplemental data are from the 2000/01 Canadian Community Health Survey. ANALYTICAL TECHNIQUES: Estimates of health conditions from the two cross-sectional files that are produced for each NPHS cycle were compared. The file with the lower proxy reporting rate was expected to yield higher prevalence rates. Multivariate analyses of the longitudinal data were used to examine associations between changes in reporting status and the incidence of the selected conditions. MAIN RESULTS: Compared with the 1998/89 General file, in which proxy reporting was more common, the 1998/99 Health file yields higher estimates of certain health conditions. Declines in proxy reporting rates over time are generally associated with greater increases in estimates. Analyses based on the longitudinal file suggest that the incidence of some conditions may also be subject to a proxy effect.

Adolescent↗
PubMed2005

Agreement between child self-report and parent proxy-report to evaluate quality of life in children with cancer.

Assessment of children' Quality of life (QOL) is a special challenge for clinicians and researchers because different cognitive abilities of children at various ages and illness levels are so varied. In addition, statistical strategies reported to evaluate proxy agreement have been inconclusive. The specific aims of this study were to examine agreement between child self-reports and parent proxy-reports to evaluate QOL in a sample of pediatric cancer patients. Previously tested QOL instruments (Quality of Life for Children with Cancer, QOLCC) were completed by 141 patients (82 children and 59 adolescents) and 141 of their parents. Three different statistical approaches were employed to evaluate convergence of self-report and proxy-report: product-moment correction coefficient, intraclass correlation (ICC), and comparison of group means. In addition, scatter bias was used to examine the degree of differences across the range of measurement. Our findings indicate that neither Pearson product correlation, ICC or group difference provided enough information to detect the individual differences of measures of QOL. We found that scatter bias should be supplemented to quantify the degree of individual-level differences. The results suggest that when children who are younger are not able to evaluate QOL assessment due to their developmental limitation or severity of illness, parents can provide valid information about their QOL. However, parent-proxy of QOL for adolescents provides significantly different information than self-report and proxy data of QOL for adolescents should be used with caution.

Adolescent↗
PubMed2004

Effectiveness and safety of the Proxis system in demonstrating retrograde coronary blood flow during proximal occlusion and in capturing embolic material.

The Feasibility And Safety Trial for its embolic protection device during transluminal intervention in coronary vessels: a European Registry (FASTER) was designed to demonstrate that (1) the Proxis embolic protection system can control anterograde flow and reverse blood flow in native coronary arteries and saphenous vein grafts; and (2) this system can capture embolic debris. Percutaneous coronary intervention on stenotic coronary lesions revolutionized treatment of coronary disease, but is associated with the risk of major adverse cardiac events. This prospective, nonrandomized, multicenter clinical feasibility and safety study enrolled 40 patients with 51 lesions at 4 centers who underwent treatment of stenotic lesions with proximal emboli protection (Proxis system). Proxis was successfully used 95% of the time, and embolic debris was qualitatively identified in all cases. Major adverse cardiac events occurred in 2 patients (5.0%): 1 late in-stent thrombosis resulting in death and 1 non-Q-wave infarction when a lesion was crossed before deployment of the Proxis system. Mean vessel occlusion time was 4.3 +/- 2.4 minutes. Native flow reversal was sufficient in 31 patients, with a mean aspirate volume of 11.8 +/- 6.5 ml. When the infusion catheter was used to augment reflow, mean occlusion time was 4.6 minutes. In conclusion, this trial is the first to demonstrate that retrograde blood flow can be achieved during proximal occlusion and that the Proxis system can be used safely during intervention of saphenous vein grafts and native coronary arterial lesions to capture embolic material.

Aged↗
PubMed2000

Use of twins as mutual proxy respondents in a case-control study of breast cancer: effect of item nonresponse and misclassification.

A case-control study of breast cancer in twins diagnosed before 1988 was used to characterize the effects on odds ratios when proxy responses from co-twins are used. North American disease-discordant pairs were ascertained through advertisements, and mailed questionnaires were returned from both members of 671 pairs and from one member of 391 pairs. Biases from the proxy response were attributed to nonresponse or misclassification. Nonresponse varied according to type of exposure variable, depth of detail requested, joint exposure status of the pair, respondent's case-control status, zygosity, and social closeness of the pair. Misclassification was minimal, generally nondifferential, and a high degree of reliability between the proxy and self-report was indicated by the kappa statistic and the intraclass correlation coefficient. By using double-respondent pairs, a method was developed to adjust proxy responses for both sources of bias. These adjustments resulted in minor changes to the odds ratios for the variables studied (age at menarche, reproductive factors, and hormone use). A larger difference was observed between the odds ratios based on all pairs and those based on double-respondent pairs only. These findings demonstrate that, for these variables in this population, twins are reliable proxies for each other and that results from single-respondent pairs should be included.

Breast Neoplasms↗
PubMed1992

Proxy respondents and the validity of occupational and other exposure data. The Selected Cancers Cooperative Study Group.

As part of a multicenter cancer case-control study conducted in 1984-1988, a proxy interview was attempted for all cases who were initially interviewed for the study but who died during the 4-year data collection period. To assess the validity of using wives, other relatives, or other informants to obtain information about a subject, the authors compared occupational and other exposure data obtained from 270 male cancer cases and their proxy respondents. The primary focus of the case-control study was on Vietnam military service and exposure to phenoxy herbicides, but cases and their proxy respondents were also asked about occupational and other exposures relevant to the cancers. The accuracy of reporting for specific occupational exposures (e.g., asbestos and formaldehyde) and specific occupations (e.g., dry cleaning and meat packing or processing) was poor, although the latter improved somewhat when only case-spouse pairs were examined. Similarly, there was poor sensitivity in the reporting of herbicide exposure information in farming and other related occupations. In contrast, the reporting of certain demographic characteristics, childhood history characteristics, and use of alcohol and cigarettes was relatively good, and was even better when only case-spouse pairs were examined. The poor quality of proxy information for detailed exposure information suggests the need for careful use and interpretation of proxy information in epidemiologic studies.

Adult↗
PubMed1993

Data on prior pesticide use collected from self- and proxy respondents.

Proxy respondents have often been used in case-control studies of cancer and pesticides. To evaluate the effect of exposure misclassification, we compared data collected during 1981-1983 from participants interviewed for a case-control study of leukemia and non-Hodgkin's lymphoma with data collected during 1990-1991 from proxy respondents for participants who died or became incompetent since the initial interview (328 self-proxy pairs). As questions increased in detail, agreement percentages decreased. Agreement percentages were highest for demographic and general farming information (averages = 88-90%) and lowest for specific pesticide use (averages = 68-74%). Generally, odds ratios calculated from proxy respondent data were less than those from self-respondent data; however, several exceptions occurred. The findings indicate that pesticide data provided by proxy respondents will not necessarily result in the same estimate of risk and/or lead to the same conclusions as data provided by self-respondents.

Adult↗
PubMed1984

Research note: proxy responses in health surveys: a methodological issue.

The practice of using proxy respondents in health surveys has been identified as a possible cause of confusion in the literature concerning sex differences in morbidity. Specifically, it has been suggested that proxy respondents (usually female) tend to under-report illnesses of absent persons (usually male) and hence the observation that women suffer from more illness than men may simply be an artifact of this method of data collection. In order to investigate proxy effects, 50 married couples were asked to report symptoms recently experienced by their spouses as well as themselves. A high level of agreement was found between husbands and wives regarding the number and severity of symptoms experienced by each individual, despite considerable differences in health status between sub-groups. Where there was a discrepancy, it was in the direction of the proxy respondent (of either sex) over-reporting symptoms. It follows from this that, if anything, the over-use of female interviewees would tend to minimise observed sex differences in illness. Thus, the excess female morbidity found in health surveys is not attributable to proxy effects but is more likely to result from differences in the way in which men and women experience symptoms.

Female↗
PubMed1997

The proxy model of social comparison for self-assessment of ability.

One purpose of the social comparison of abilities is to determine action possibilities-"Can I do X?" By comparing ourselves with a proxy who has attempted X, we can determine our likelihood of success. A good proxy is one who has performed the same as us on an initial task requiring the ability. In addition, however, a good proxy must be similar on related attributes so that we can be confident that the proxy's performance on the initial task was maximal. In the case of a task requiring multiple abilities, more than one proxy may be used.

Journal Article↗
PubMed2005

Use of proxies and reference quintiles obtained from minimal model analysis for determination of insulin sensitivity and pancreatic beta-cell responsiveness in horses.

OBJECTIVE: To develop proxies calculated from basal plasma glucose and insulin concentrations that predict insulin sensitivity (SI; L.min(-1) x mU(-1)) and beta-cell responsiveness (ie, acute insulin response to glucose [AIRg]; mU/L x min(-1)) and to determine reference quintiles for these and minimal model variables. ANIMALS: 1 laminitic pony and 46 healthy horses. PROCEDURE: Basal plasma glucose (mg/dL) and insulin (mU/L) concentrations were determined from blood samples obtained between 8:00 AM and 9:00 AM. Minimal model results for 46 horses were compared by equivalence testing with proxies for screening SI and pancreatic beta-cell responsiveness in humans and with 2 new proxies for screening in horses (ie, reciprocal of the square root of insulin [RISQI] and modified insulin-to-glucose ratio [MIRG]). RESULTS: Best predictors of SI and AIRg were RISQI (r = 0.77) and MIRG (r = 0.75) as follows: SI = 7.93(RISQI) - 1.03 and AIRg = 70.1(MIRG) - 13.8, where RISQI equals plasma insulin concentration(-0.5) and MIRG equals [800 - 0.30(plasma insulin concentration 50)(2)]/(plasma glucose concentration - 30). Total predictive powers were 78% and 80% for RISQI and MIRG, respectively. Reference ranges and quintiles for a population of healthy horses were calculated nonparametrically. CONCLUSIONS AND CLINICAL RELEVANCE: Proxies for screening SI and pancreatic beta-cell responsiveness in horses from this study compared favorably with proxies used effectively for humans. Combined use of RISQI and MIRG will enable differentiation between compensated and uncompensated insulin resistance. The sample size of our study allowed for determination of sound reference range values and quintiles for healthy horses.

Animals↗
PubMed1986

The reporting of stigmatizing health conditions: a comparison of proxy and self-reporting.

Previous studies have found that self-respondents tend to report a greater number of health problems than do household proxies. It has not been clear, however, if such results indicate reporting bias or reflect underlying health differences in the self-respondent and household proxy populations. Verification data from a survey of medical providers were examined in conjunction with the results of a national household survey. Our analysis indicates that the use of proxies does not increase misreporting. Overall reporting error between self-respondents and proxy-respondents is comparable on reports of mental illness. When physical stigmatizing conditions are examined, the use of proxies actually appears to be preferable to interviewing respondents directly.

Community Participation↗
PubMed2000

Measuring living standards with proxy variables.

Very few demographic surveys in developing countries have gathered information on household incomes or consumption expenditures. Researchers interested in living standards therefore have had little alternative but to rely on simple proxy indicators. The properties of these proxies have not been analyzed systematically. We ask what hypotheses can be tested using proxies, and compare these indicators with consumption expenditures per adult, our preferred measure of living standards. We find that the proxies employed in much demographic research are very weak predictors of consumption per adult. Nevertheless, hypothesis tests based on proxies are likely to be powerful enough to warrant consideration.

Adult↗
PubMed1995

Munchausen syndrome by proxy and factitious illness: symptomatology, parent-child interaction, and psychopathology of the parents.

The term Munchausen syndrome by proxy is used to diagnose children presenting symptoms of an organic disorder resulting from manipulations initiated by their caretakers. Even in early infancy it happens that injuries are induced, and that drugs, poisons or medicine are administered in order to provoke and feign clinical symptoms of severe diseases. Exact data on prevalence are not available but it is obvious that Munchausen syndrome by proxy is a rare psychiatric disorder. There is a body of evidence that Munchausen syndrome by proxy is nothing but the extreme of a broader clinical entity for which the term factitious illness has been introduced. In this group children are included whose mothers invent a history of disease in order to produce symptoms without actually damaging their children. It is not well established whether such a distinction is necessary and whether there are differences in long-term outcome. Onset of symptoms is as early as three weeks up to twelve years, and mean age of diagnosis according to a more comprehensive study is 3 1/4 year. The estimated mortality rate of children with Munchausen syndrome by proxy is 9 percent. In three of the four cases of children reported here clinical presentations were dominated by symptoms of central nervous disorders. All mothers showed unsure and inconsistent parental behaviour and inefficient coping. None of them received support from their partners, if present. In interaction the children always wanted to dominate their mothers. The high amount of personality disorders observed in the caretakers might be the reason for the often reported failure of psychotherapeutic interventions.

Child↗