Neil K. Aaronson

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

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-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.

Translating Health Status Questionnaires and Evaluating Their Quality : The IQOLA Project Approach

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.

Health-related quality of life associated with chronic conditions in eight countries: Results from the International Quality of Life Assessment (IQOLA) Project

Context: Few studies and no international comparisons have examined the impact of multiple chronic conditions on populations using a comprehensive health-related quality of life (HRQL) questionnaire. Objective: The impact of common chronic conditions on HRQL among the general populations of eight countries was assessed. Design: Cross-sectional mail and interview surveys were conducted. Participants and setting: Sample representatives of the adult general population of eight countries (Denmark, France, Germany, Italy, Japan, the Netherlands, Norway and the United States) were evaluated. Sample sizes ranged from 2031 to 4084. Main outcome measures: Self-reported prevalence of chronic conditions (including allergies, arthritis, congestive heart failure, chronic lung disease, hypertension, diabetes, and ischemic heart disease), sociodemographic data and the SF-36 Health Survey were obtained. The SF-36 scale and summary scores were estimated for individuals with and without selected chronic conditions and compared across countries using multivariate linear regression analyses. Adjustments were made for age, gender, marital status, education and the mode of SF-36 administration. Results: More than half (55.1%) of the pooled sample reported at least one chronic condition, and 30.2% had more than one. Hypertension, allergies and arthritis were the most frequently reported conditions. The effect of ischemic heart disease on many of the physical health scales was noteworthy, as was the impact of diabetes on general health, or arthritis on bodily pain scale scores. Arthritis, chronic lung disease and congestive heart failure were the conditions with a higher impact on SF-36 physical summary score, whereas for hypertension and allergies, HRQL impact was low (comparing with a typical person without chronic conditions, deviation scores were around −4 points for the first group and −1 for the second). Differences between chronic conditions in terms of their impact on SF-36 mental summary score were low (deviation scores ranged between −1 and −2). Conclusions: Arthritis has the highest HRQL impact in the general population of the countries studied due to the combination of a high deviation score on physical scales and a high frequency. Impact of chronic conditions on HRQL was similar roughly across countries, despite important variation in prevalence. The use of HRQL measures such as the SF-36 should be useful to better characterize the global burden of disease.

The EORTC QLQ-LC13: a modular supplement to the EORTC core quality of life questionnaire (QLQ-C30) for use in lung cancer clinical trials

The EORTC Study Group on Quality of Life has developed a modular system for assessing the quality of life of cancer patients in clinical trials composed of two basic elements: (1) a core quality of life questionnaire, the EORTC QLQ-C30, covering general aspects of health-related quality of life, and (2) additional disease- or treatment-specific questionnaire modules. Two international field studies were carried out to evaluate the practicality, reliability and validity of the core questionnaire, supplemented by a 13-item lung cancer-specific questionnaire module, the EORTC QLQ-LC13. In this paper, the results of an evaluation of the QLQ-LC13 are reported. The lung cancer questionnaire module comprises both multi-item and single-item measures of lung cancer-associated symptoms (i.e. coughing, haemoptysis, dyspnoea and pain) and side-effects from conventional chemo- and radiotherapy (i.e. hair loss, neuropathy, sore mouth and dysphagia). It was administered to patients with non-resectable lung cancer recruited from 17 countries. In total, 883 and 735 patients, respectively, completed the questionnaire prior to and once during treatment. The symptom measures discriminated clearly between patients differing in performance status. All item scores changed significantly in the expected direction (i.e. lung cancer symptoms decreased and treatment toxicities increased) during treatment. With one exception (problems with a sore mouth), the change of toxicity measures over time was related specifically to either chemo- or radiotherapy. However, the single item on neuropathy did not measure adequately the full range of symptoms. The hypothesised scale structure of the questionnaire was partially supported by the data. The multi-item dyspnoea scale met the minimal standards for reliability (Cronbach alpha coefficient > 0.70), while the pain items did not form a scale with reliability estimates acceptable for group comparisons. In conclusion, the results form international field testing lend support to the EORTC QLQ-LC13 as a clinically valid and useful tool for assessing disease- and treatment-specific symptoms in lung cancer patients participating in clinical trials, when combined with the EORTC core quality of life questionnaire. In a few areas, however, the questionnaire module could benefit from further refinements. In addition, its performance over a longer period of time still needs to be investigated.

International quality of life assessment (IQOLA) project

The International Quality of Life Assesment (IQOLA) Project is a 4-year project to translate and adapt the widely used MOS SF-36 Health Survey Questionnaire in up to 15 countries and validate, norm, and document the new translations as required for their use in international studies of health outcomes. In addition to the eight-scale SF-36 health profile, the project will also validate psychometrically based physical and mental health summary scores, as well as health utility indexes incorporating SF-36 scales for use in cost-utility studies.

Evaluating quality-of-life and health status instruments: development of scientific review criteria

The Medical Outcomes Trust is a depository and distributor of high-quality, standardized, health outcomes measurement instruments to national and international health communities. Every instrument in the Trust library is reviewed by the Scientific Advisory Committee against a rigorous set of eight attributes. These attributes consist of the following: (1) conceptual and measurement model; (2) reliability; (3) validity; (4) responsiveness; (5) interpretability; (6) respondent and administrative burden; (7) alternative forms; and (8) cultural and language adaptations. In addition to a full description of each attribute, we discuss uses of these criteria beyond evaluation of existing instruments and lessons learned in the first few rounds of instrument review against these criteria.

The factor structure of the SF-36 Health Survey in 10 countries: Results from the IQOLA Project

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.

Physical Exercise in Cancer Patients During and After Medical Treatment: A Systematic Review of Randomized and Controlled Clinical Trials

PURPOSE To systematically review the methodologic quality of, and summarize the evidence from trials examining the effectiveness of physical exercise in improving the level of physical functioning and psychological well-being of cancer patients during and after medical treatment. METHODS Thirty-four randomized clinical trials (RCTs) and controlled clinical trials were identified, reviewed for substantive results, and assessed for methodologic quality. RESULTS Four of 34 trials met all (seven of seven) methodologic criteria on the Delphi criteria list. Failure to conceal the sequencing of treatment allocation before patient recruitment, failure to blind the outcome assessor, and failure to employ an intention-to-treat analysis strategy were the most prevalent methodologic shortcomings. Various exercise modalities have been applied, differing in content, frequency, intensity, and duration. Positive results have been observed for a diverse set of outcomes, including physiologic measures, objective performance indicators, self-reported functioning and symptoms, psychological well-being, and overall health-related quality of life. CONCLUSION The trials reviewed were of moderate methodologic quality. Together they suggest that cancer patients may benefit from physical exercise both during and after treatment. However, the specific beneficial effects of physical exercise may vary as a function of the stage of disease, the nature of the medical treatment, and the current lifestyle of the patient. Future RCTs should use larger samples, use appropriate comparison groups to rule out the possibility of an attention-placebo effect, use a comparable set of outcome measures, pay greater attention to issues of motivation and adherence of patients participating in exercise programs, and examine the effect of exercise on cancer survival.

The Equivalence of SF-36 Summary Health Scores Estimated Using Standard and Country-Specific Algorithms in 10 Countries: Results from the IQOLA Project

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.