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G Apolone

Publications and source records attributed to G Apolone.

At least 37 records · Page 2Linked to original sources
PubMed2000

One model, several results: the paradox of the Hosmer-Lemeshow goodness-of-fit test for the logistic regression model.

BACKGROUND: The Hosmer-Lemeshow test, used extensively to assess the fit of the logistic regression model, is performed by several statistical packages. Recent studies have shown some problems in the use of this test when ties are present. These problems were attributed merely to the test implementation. METHODS: We analysed the order of the observations as an alternative explanation of the problem of ties. Using a data-set of 1393 intensive care unit (ICU) patients we performed the Hosmer-Lemeshow test with all possible subjects dispositions. RESULTS: We obtained about one million different P values, ranging from 0.01 to 0.95. DISCUSSION: It is already known that when the Hosmer-Lemeshow goodness-of-fit test is performed with a number of covariate patterns lower than the number of subjects, its result may be inaccurate. We showed that the extent of this problem could be relevant under particular conditions. We also suggest a strategy for estimating the extent of the problem and subsequent interpretation.

Hospital Mortality↗
PubMed1999

Quality of life in women with recurrent breast cancer.

Although the psychosocial concomitants of early-stage breast cancer have been well-documented, the relationship between cancer recurrence and quality of life remains less clear. We conducted a prospective, longitudinal study in order to clarify the relationship between recurrent cancer and quality of life, and to determine predictors of quality of life following recurrence. Sixty-nine women with recurrent breast cancer completed questionnaires assessing multiple components of quality of life at three time points: prior to recurrence, immediately after the diagnosis of recurrence, and at follow-up 6 months later. Perceptions of overall quality of life, general health status, emotional, social, and physical functioning were poorer immediately following the diagnosis of recurrence than they had been prior to recurrence. These women also evidenced significant improvement in several domains of quality of life between initial recurrence and follow-up; nonetheless, most areas of quality of life were impaired compared to pre-recurrence. Self-reported physical symptoms were a strong predictor of post-recurrence ratings of overall quality of life. These data suggest that the recurrence of breast cancer is associated with significant changes in quality of life. Quality of life did not progressively deteriorate, however, attesting to the resilience of women coping with this major stressor. These data shed light on issues of potential importance to patients managing this serious illness and may have implications for health-care professionals working with this population.

Aged↗
PubMed1999

Health-related quality of life in dialysis patients. A report from an Italian study using the SF-36 Health Survey. DIA-QOL Group.

BACKGROUND: Interest in measuring health-related quality of life (HRQoL) has increased together with an awareness that such humanistic outcomes require valid and reliable measures. In the last decade short, simple and multidimensional generic and disease-specific questionnaires have been developed. Among the several generic questionnaires available, the Short Form 36 Items Health Survey (SF-36) was translated and validated in several languages, and applied to different settings and diseases. METHODS: Within the framework of a larger, prospective, multicentre study (DIA-QOL project) the SF-36 was administered to 304 patients to test its characteristics in terms of patient acceptability, and psychometric and clinical validity. Standard psychometric techniques were used to evaluate its validity in terms of convergence, divergence and internal consistency reliability (Cronbach's alpha). Correlations between clinical variables and HRQoL scores were performed to test the questionnaire's capability to capture differences across patients groups. RESULTS: Overall, the findings show that, in this sample, the SF-36's performance was very good. Acceptability was satisfactory, with a response rate higher than 80%. All the questionnaire scales met the psychometric standards suggested in terms of grouping and scaling assumptions. The internal reliability coefficients actually replicate the satisfactory findings reported previously for the original SF-36. In terms of the ability of the questionnaire scales to discriminate between groups expected to differ in a given health concept in relation to clinical variables, the results were also good. On average, females reported lower scores, the impact of ageing was more evident for physical scales. Diabetic patients score significantly worse on the physical function scale and patients with mental health problems score significantly lower on the mental health scale. No significant association was found with the index KtV, haemoglobin levels, body mass index, parathyroid hormone and type of dialysis. A strong association was indeed found between SF-36 scales measuring physical health concepts and the serum albumin level. This association held after adjusting for the confounding effect of age. Comparison of the health profile of the present sample with others from the US and UK and from a representative sample of the Italian general population highlights the potential of such questionnaire in dialysis setting. CONCLUSIONS: The SF-36 questionnaire is easy to use in Italian dialysis patients and SF-36 scores are related to important clinical aspects. This approach can help in caring for dialysis patients and can be useful in outcome assessment programmes.

Adult↗
PubMed1999

Measuring quality of life in dyspeptic patients: development and validation of a new specific health status questionnaire: final report from the Italian QPD project involving 4000 patients.

OBJECTIVE: Despite the fact that gastrointestinal disorders represent one of the most common reasons for medical consultations, formal assessment of patients' health-related quality of life (HRQOL) has been carried out only in a few studies, and in most cases generic questionnaires have been adopted. Because the specific issue of living with dyspeptic problems has been addressed in very few cases and no questionnaire has been shown to be appropriate for the Italian setting, a prospective project was launched to develop a specific HRQOL questionnaire for dyspepsia sufferers tailored to Italian patients but also appropriate in other cultural settings. METHODS: The project consisted in a 3-yr, three-phase survey, in which different versions of the quality of life in peptic disease questionnaire (QPD) were developed through expert and patient focus groups and empiric field studies and then administered to patients recruited in five multicenter studies. Standard psychometric techniques were used to evaluate the validity, reliability, responsiveness, and patient acceptability of the QPD. RESULTS: Three different versions of the QPD questionnaire were self-administered to more than 4000 patients. The final 30-item version, measuring three health concepts related to dyspeptic disease (anxiety induced by pain, social restriction, symptom perception), fulfilled the recommended psychometric criteria in terms of reliability and validity, correlated with health concepts measured with a well-known independent generic HRQOL instrument (the SF-36 Health Survey questionnaire) and was relatively invariant to diagnosis and sociodemographic variables; it also correlated with a measure of gastric pain frequency and was able to detect meaningful differences over time. CONCLUSIONS: Although further validation studies in different cultural and linguistic settings are mandatory before any firm conclusions can be drawn regarding the cross-cultural validity of the QPD, the data obtained provide evidence of the psychometric validity and robustness of the questionnaire when used in a fairly large, well-characterized population of Italian dyspeptic patients.

Adult↗
PubMed1998

Adjuvant portal-vein infusion of fluorouracil and heparin in colorectal cancer: a randomised trial. European Organisation for Research and Treatment of Cancer Gastrointestinal Tract Cancer Cooperative Group, the Gruppo Interdisciplinare Valutazione Interventi in Oncologia, and the Japanese Foundation for Cancer Research.

BACKGROUND: There is conflicting evidence on the efficacy of regional adjuvant chemotherapy, via portal-vein infusion (PVI), after resection of colorectal cancer. We undertook a randomised controlled multicentre trial to investigate the efficacy of PVI (500 mg/m2 fluorouracil plus 5000 IU heparin daily for 7 days). METHODS: 1235 of about 1500 potentially eligible patients were randomly assigned surgery plus PVI or surgery alone (control). The patients were followed up for a median of 63 months, with yearly screening for recurrent disease. The primary endpoint was survival; analyses were by intention to treat. FINDINGS: 619 patients in the control group and 616 in the PVI group met eligibility criteria. 164 (26%) control-group patients and 173 (28%) PVI-group patients died. 5-year survival did not differ significantly between the groups (73 vs 72%; 95% Cl for difference -6 to 4). The control and PVI groups were also similar in terms of disease-free survival at 5 years (67 vs 65%) and the number of patients with liver metastases (79 vs 77%). INTERPRETATION: PVI of fluorouracil, at a dose of 500 mg/m2 for 7 days, cannot be recommended as the sole adjuvant treatment for high-risk colorectal cancer after complete surgical excision. However, these results cannot eliminate a small benefit when PVI is used at a higher dosage or in combination with mitomycin.

Aged↗
PubMed1998

GIVIO-SITAC 01: A randomized trial of adjuvant 5-fluorouracil and folinic acid administered to patients with colon carcinoma--long term results and evaluation of the indicators of health-related quality of life. Gruppo Italiano Valutazione Interventi in Oncologia. Studio Italiano Terapia Adiuvante Colon.

BACKGROUND: In 1989, the authors began a randomized trial to determine whether 5-fluorouracil and high dose folinic acid (HD-FUFA) would increase the event free and overall survival of patients with resectable Dukes B and C (AJCC/UICC Stage II and Stage III) colon carcinoma, and to assess the toxicity of the treatment and its impact on selected health-related quality-of-life indicators. Early results were published as a part of an international multicenter pooled analysis (IMPACT) in 1995. The purpose of this report is to update the survival data for patients enrolled in the trial and describe their reported perceptions of their own health and quality of life. METHODS: The trial involved multiple treatment centers, with a centralized randomization between surgery alone and surgery with chemotherapy. The HD-FUFA regimen employed consisted of 5-fluorouracil (370 mg/m2) plus folinic acid (200 mg/m2) administered daily for 5 days every 4 weeks for 6 cycles. Patients' perceptions of their own health status were obtained by means of 3 self-administered questionnaires, which were completed by patients at the time of discharge from the treatment center and at 6 and 24 months after randomization. RESULTS: Overall, 888 patients with resected Dukes B2 and C colon carcinoma were enrolled in the trial. HD-FUFA significantly reduced mortality by 25% (95% confidence interval, 5-41%; P=0.02) and events by 31% (95% confidence interval, 14-45%; P < or = 0.001). Compliance with treatment was good; more than 80% of patients completed the planned therapy. Toxicity was mild, and oral mucositis was the main side effect. None of the health-related quality-of-life parameters investigated (emotional status, worry about the future, changes in social life, impact of the disease, follow-up, and global quality of life) seemed to be affected by the treatment to which patients were allocated. A positive trend in the evolution of patients' psychologic status was observed. CONCLUSIONS: Long term results of this SITAC study confirm that HD-FUFA is a well-tolerated, effective 6-month adjuvant regimen for patients with colon carcinoma that has no detrimental effect on their quality of life.

Adult↗
PubMed1998

Evaluation of the uniformity of fit of general outcome prediction models.

OBJECTIVE: To compare the performance of the New Simplified Acute Physiology Score (SAPS II) and the New Admission Mortality Probability Model (MPM II0) within relevant subgroups using formal statistical assessment (uniformity of fit). DESIGN: Analysis of the database of a multi-centre, multi-national and prospective cohort study, involving 89 ICUs from 12 European Countries. SETTING: Database of EURICUS-I. PATIENTS: Data of 16,060 patients consecutively admitted to the ICUs were collected during a period of 4 months. Following the original SAPS II and MPM II0 criteria, the following patients were excluded from the analysis: younger than 18 years of age; readmissions; acute myocardial infarction; burn cases; patients in the post-operative period after coronary artery bypass surgery and patients with a length of stay in the ICU shorter than 8 h, resulting in a total of 10,027 cases. INTERVENTIONS: Data necessary for the calculation of SAPS II and MPM II0, basic demographic statistics and vital status on hospital discharge were recorded. Formal evaluation of the performance of the models, comprising discrimination (area under ROC curve), calibration (Hosmer-Lemeshow goodness-of-fit H and C tests) and observed/expected mortality ratios within relevant subgroups. MAIN RESULTS: Better predictive accuracy was achieved in elective surgery patients admitted from the operative room/post-anaesthesia room with gastrointestinal, neurological or trauma diagnoses, and younger patients with non-operative neurological, septic or trauma diagnoses. All these characteristics appear to be linked to a lower severity of illness, with both models overestimating mortality in the more severely ill patients. CONCLUSIONS: Concerning the performance of the models, very large differences were apparent in relevant subgroups, varying from excellent to almost random predictive accuracy. These differences can explain some of the difficulties of the models to accurately predict mortality when applied to different populations with distinct patient baseline characteristics. This study stresses the importance of evaluating multiple diverse populations (to generate the design set) and of methods to improve the validation set before extrapolations can be made from the validation setting to new independent populations. It also underlines the necessity of a better definition of the patient baseline characteristics in the samples under analysis and the formal statistical evaluation of the application of the models to specific subgroups.

Europe↗
PubMed1998

Translating health status questionnaires and evaluating their quality: the IQOLA Project approach. International Quality of Life Assessment.

This article describes the methods adopted by the International Quality of Life Assessment (IQOLA) project to translate the SF-36 Health Survey. Translation methods included the production of forward and backward translations, use of difficulty and quality ratings, pilot testing, and cross-cultural comparison of the translation work. Experience to date suggests that the SF-36 can be adapted for use in other countries with relatively minor changes to the content of the form, providing support for the use of these translations in multinational clinical trials and other studies. The most difficult items to translate were physical functioning items, which used examples of activities and distances that are not common outside of the United States; items that used colloquial expressions such as pep or blue; and the social functioning items. Quality ratings were uniformly high across countries. While the IQOLA approach to translation and validation was developed for use with the SF-36, it is applicable to other translation efforts.

Cross-Cultural Comparison↗
PubMed1998

Cross-cultural comparisons of the content of SF-36 translations across 10 countries: results from the IQOLA Project. International Quality of Life Assessment.

Increasingly, translated and culturally adapted health-related quality of life measures are being used in cross-cultural research. To assess comparability of results, researchers need to know the comparability of the content of the questionnaires used in different countries. Based on an item-by-item discussion among International Quality of Life Assessment (IQOLA) investigators of the content of the translated versions of the SF-36 in 10 countries, we discuss the difficulties that arose in translating the SF-36. We also review the solutions identified by IQOLA investigators to translate items and response choices so that they are appropriate within each country as well as comparable across countries. We relate problems and solutions to ratings of difficulty and conceptual equivalence for each item. The most difficult items to translate were physical functioning items that refer to activities not common outside the United States and items that use colloquial expressions in the source version. Identifying the origin of the source items, their meaning to American English-speaking respondents and American English synonyms, in response to country-specific translation issues, greatly helped the translation process. This comparison of the content of translated SF-36 items suggests that the translations are culturally appropriate and comparable in their content.

Cross-Cultural Comparison↗
PubMed1998

Testing the equivalence of translations of widely used response choice labels: results from the IQOLA Project. International Quality of Life Assessment.

The similarity in meaning assigned to response choice labels from the SF-36 Health Survey (SF-36) was evaluated across countries. Convenience samples of judges (range, 10 to 117; median = 48) from 13 countries rated translations of response choice labels, using a variation of the Thurstone method of equal appearing intervals. Judges marked a point on a 10-cm line-representing the magnitude of a response choice label (e.g., "good" relative to the anchors of "poor" and "excellent"). Ratings were evaluated to determine the ordinal consistency of response choice labels within a response scale; the degree to which differences between adjacent response choice labels were equal interval; and the amount of variance due to response choice label, country, judge, and interaction between response choice label and country. Results confirmed the hypothesized ordering of response choice labels; the percentage of ordinal pairs ranged from 88.7% to 100% (median = 98.2%) across countries and response scales. Examination of the average magnitudes of response choice labels supported the "quasi-interval" nature of the scales. Analysis of variance (ANOVA) results supported the generalizability of response choice magnitudes across countries; labels explained 64% to 77% of the variance in ratings, and country explained 1% to 3%. These results support the equivalence of SF-36 response choice labels across countries. Departures from the assumption of equal intervals, when observed, were similar across countries and were greatest for the two response scales that are recalibrated under standard SF-36 scoring. Results provide justification for scoring translations of individual items using standard SF-36 scoring; whether these items form the same scales in other countries as they do in the United States is evaluated with tests of scaling assumptions.

Analysis of Variance↗
PubMed1998

The Italian SF-36 Health Survey: translation, validation and norming.

This article reports on the development and validation of the Italian SF-36 Health Survey using data from seven studies in which an Italian version of the SF-36 was administered to more than 7000 subjects between 1991 and 1995. Empirical findings from a wide array of studies and diseases indicate that the performance of the questionnaire improved as the Italian translation was revised and that it met the standards suggested by the literature in terms of feasibility, psychometric tests, and interpretability. This generally satisfactory picture strengthens the idea that the Italian SF-36 is as valid and reliable as the original instrument and applicable and valid across age, gender, and disease. Empirical evidence from a cross-sectional survey carried out to norm the final version in a representative sample of 2031 individuals confirms the questionnaire's characteristics in terms of hypothesized constructs and psychometric behavior and gives a better picture of its external validity (i.e., robustness and generalizability) when administered in settings that are very close to real world.

Cross-Cultural Comparison↗
PubMed1998

Tests of data quality, scaling assumptions, and reliability of the SF-36 in eleven countries: results from the IQOLA Project. International Quality of Life Assessment.

Data from general population samples in 11 countries (n = 1483 to 9151) were used to assess data quality and test the assumptions underlying the construction and scoring of multi-item scales from the SF-36 Health Survey. Across all countries, the rate of item-level missing data generally was low, although slightly higher for items printed in the grid format. In each country, item means generally were clustered as hypothesized within scales. Correlations between items and hypothesized scales were greater than 0.40 with one exception, supporting item internal consistency. Items generally correlated significantly higher with their own scale than with competing scales, supporting item discriminant validity. Scales could be constructed for 93-100% of respondents. Internal consistency reliability of the eight SF-36 scales was above 0.70 for all scales, with two exceptions. Floor effects were low for all except the two role functioning scales; ceiling effects were high for both role functioning scales and also were noteworthy for the Physical Functioning, Bodily Pain, and Social Functioning scales in some countries. These results support the construction and scoring of the SF-36 translations in these 11 countries using the method of summated ratings.

Cross-Cultural Comparison↗
PubMed1998

The factor structure of the SF-36 Health Survey in 10 countries: results from the IQOLA Project. International Quality of Life Assessment.

Studies of the factor structure of the SF-36 Health Survey are an important step in its construct validation. Its structure is also the psychometric basis for scoring physical and mental health summary scales, which are proving useful in simplifying and interpreting statistical analyses. To test the generalizability of the SF-36 factor structure, product-moment correlations among the eight SF-36 Health Survey scales were estimated for representative samples of general populations in each of 10 countries. Matrices were independently factor analyzed using identical methods to test for hypothesized physical and mental health components, and results were compared with those published for the United States. Following simple orthogonal rotation of two principal components, they were easily interpreted as dimensions of physical and mental health in all countries. These components accounted for 76% to 85% of the reliable variance in scale scores across nine European countries, in comparison with 82% in the United States. Similar patterns of correlations between the eight scales and the components were observed across all countries and across age and gender subgroups within each country. Correlations with the physical component were highest (0.64 to 0.86) for the Physical Functioning, Role Physical, and Bodily Pain scales, whereas the Mental Health, Role Emotional, and Social Functioning scales correlated highest (0.62 to 0.91) with the mental component. Secondary correlations for both clusters of scales were much lower. Scales measuring General Health and Vitality correlated moderately with both physical and mental health components. These results support the construct validity of the SF-36 translations and the scoring of physical and mental health components in all countries studied.

Cross-Cultural Comparison↗
PubMed1998

The equivalence of SF-36 summary health scores estimated using standard and country-specific algorithms in 10 countries: results from the IQOLA Project. International Quality of Life Assessment.

Data from general population surveys (n = 1771 to 9151) in nine European countries (Denmark, France, Germany, Italy, the Netherlands, Norway, Spain, Sweden, and the United Kingdom) were analyzed to test the algorithms used to score physical and mental component summary measures (PCS-36/MCS-36) based on the SF-36 Health Survey. Scoring coefficients for principal components were estimated independently in each country using identical methods of factor extraction and orthogonal rotation. PCS-36 and MCS-36 scores were also estimated using standard (U.S.-derived) scoring algorithms, and results were compared. Product-moment correlations between scores estimated from standard and country-specific scoring coefficients were very high (0.98 to 1.00) for both physical and mental health components in all countries. As hypothesized for orthogonal components, correlations between physical and mental components within each country were very low (0.00 to 0.12) for both estimation methods. Mean scores for PCS-36 differed by as much as 3.0 points across countries using standard scoring, and mean scores for MCS-36 differed across countries by as much as 6.4 points. In view of the high degree of equivalence observed within each country, using standard and country-specific algorithms, we recommend use of standard scoring algorithms for purposes of multinational studies involving these 10 countries.

Algorithms↗
PubMed1998

Cross-validation of item selection and scoring for the SF-12 Health Survey in nine countries: results from the IQOLA Project. International Quality of Life Assessment.

Data from general population surveys (n = 1483 to 9151) in nine European countries (Denmark, France, Germany, Italy, the Netherlands, Norway, Spain, Sweden, and the United Kingdom) were analyzed to cross-validate the selection of questionnaire items for the SF-12 Health Survey and scoring algorithms for 12-item physical and mental component summary measures. In each country, multiple regression methods were used to select 12 SF-36 items that best reproduced the physical and mental health summary scores for the SF-36 Health Survey. Summary scores then were estimated with 12 items in three ways: using standard (U.S.-derived) SF-12 items and scoring algorithms; standard items and country-specific scoring; and country-specific sets of 12 items and scoring. Replication of the 36-item summary measures by the 12-item summary measures was then evaluated through comparison of mean scores and the strength of product-moment correlations. Product-moment correlations between SF-36 summary measures and SF-12 summary measures (standard and country-specific) were very high, ranging from 0.94-0.96 and 0.94-0.97 for the physical and mental summary measures, respectively. Mean 36-item summary measures and comparable 12-item summary measures were within 0.0 to 1.5 points (median = 0.5 points) in each country and were comparable across age groups. Because of the high degree of correspondence between summary physical and mental health measures estimated using the SF-12 and SF-36, it appears that the SF-12 will prove to be a practical alternative to the SF-36 in these countries, for purposes of large group comparisons in which the focus is on overall physical and mental health outcomes.

Cross-Cultural Comparison↗
PubMed1998

Use of structural equation modeling to test the construct validity of the SF-36 Health Survey in ten countries: results from the IQOLA Project. International Quality of Life Assessment.

A crucial prerequisite to the use of the SF-36 Health Survey in multinational studies is the reproduction of the conceptual model underlying its scoring and interpretation. Structural equation modeling (SEM) was used to test these aspects of the construct validity of the SF-36 in ten IQOLA countries: Denmark, France, Germany, Italy, the Netherlands, Norway, Spain, Sweden, the United Kingdom, and the United States. Data came from general population surveys fielded to gather normative data. Measurement and structural models developed in the United States were cross-validated in random halves of the sample in each country. SEM analyses supported the eight first-order factor model of health that underlies the scoring of SF-36 scales and two second-order factors that are the basis for summary physical and mental health measures. A single third-order factor was also observed in support of the hypothesis that all responses to the SF-36 are generated by a single, underlying construct--health. In addition, a third second-order factors, interpreted as general well-being, was shown to improve the fit of the model. This model (including eight first-order factors, three second-order factors, and one third-order factor) was cross-validated using a holdout sample within the United States and in each of the nine other countries. These results confirm the hypothesized relationships between SF-36 items and scales and justify their scoring in each country using standard algorithms. Results also suggest that SF-36 scales and summary physical and mental health measures will have similar interpretations across countries. The practical implications of a third second-order SF-36 factor (general well-being) warrant further study.

Cross-Cultural Comparison↗
PubMed1998

Comparison of Rasch and summated rating scales constructed from SF-36 physical functioning items in seven countries: results from the IQOLA Project. International Quality of Life Assessment.

Rasch models for polytomous items were used to assess the scaling assumptions and compare item response patterns in the 10-item SF-36 physical functioning scale (PF-10) for general population respondents in Denmark, Germany, Italy, the Netherlands, Sweden, the United Kingdom, and the United States. The Rasch model of physical functioning developed in the United States was compared to models for other countries, and each country was compared to a multinational composite. Strong scale congruence across the seven countries was demonstrated; items that varied between countries and from the composite may reflect unique cultural response patterns or differences in translation. Scoring algorithms based on the Rasch model for each country were superior to the current Likert scoring in tests of relative validity (RV) in discriminating among age groups in all countries. In relation to the Likert PF-10 scoring (RV = 1.00), scores estimated using the Rasch rating scale model achieve a median RV of 1.31 (range: 1.01-1.59), while the Rasch partial credit model attained a median RV of 1.44 (range: 1.01-2.23). Rasch models hold good potential for improving health status measures, estimating individual scores when responses to scale items are missing, and equating scores across countries.

Aged↗