Anita K. Wagner

Segmented regression analysis of interrupted time series studies in medication use research.

Interrupted time series design is the strongest, quasi‐experimental approach for evaluating longitudinal effects of interventions. Segmented regression analysis is a powerful statistical method for estimating intervention effects in interrupted time series studies. In this paper, we show how segmented regression analysis can be used to evaluate policy and educational interventions intended to improve the quality of medication use and/or contain costs.

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.

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.

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 comparisons of the content of SF-36 translations across 10 countries : Results from the IQOLA project

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 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.

Methods for estimating confidence intervals in interrupted time series analyses of health interventions.

OBJECTIVE Interrupted time series (ITS) is a strong quasi-experimental research design, which is increasingly applied to estimate the effects of health services and policy interventions. We describe and illustrate two methods for estimating confidence intervals (CIs) around absolute and relative changes in outcomes calculated from segmented regression parameter estimates. STUDY DESIGN AND SETTING We used multivariate delta and bootstrapping methods (BMs) to construct CIs around relative changes in level and trend, and around absolute changes in outcome based on segmented linear regression analyses of time series data corrected for autocorrelated errors. RESULTS Using previously published time series data, we estimated CIs around the effect of prescription alerts for interacting medications with warfarin on the rate of prescriptions per 10,000 warfarin users per month. Both the multivariate delta method (MDM) and the BM produced similar results. CONCLUSION BM is preferred for calculating CIs of relative changes in outcomes of time series studies, because it does not require large sample sizes when parameter estimates are obtained correctly from the model. Caution is needed when sample size is small.

Treatment of Migraine

This invention relates to a method for treating classical migraine headaches. Pursuant to this method, a therapeutic amount of β-adrenergic-blocking agent is administered to a person suffering a migraine attack promptly upon onset of aura. The invention further relates to a method wherein the blocking agent is nasally administered.

Potentially Inappropriate Medication Use by Elderly Persons in U.S. Health Maintenance Organizations, 2000–2001

Objectives: To determine rates of potentially inappropriate medication use in elderly persons in managed care plans in the United States in 2000–2001.

Advances in methods for assessing the impact of epilepsy and antiepileptic drug therapy on patients' health-related quality of life

We studied 31 previously validated and newly developed generic and epilepsy-specific scales to evaluate their usefulness for assessing the impact of epilepsy and anti-epileptic drug (AED) therapy on health-related quality of life (HRQOL). Included were the MOS SF-36 Health Survey, additional measures of mental health, cognition, epilepsy-specific perception of control, behavioural problems, distress, worries and experiences, the Liverpool Epilepsy Impact and Seizure Severity scales, and a patient-completed symptom checklist. Questionnaires were completed twice by 136 patients on AED therapy in a multicentre study in the UK. Validity was assessed in relation to disease severity, defined as time since last seizure, and to patient-reported symptoms. Statistical analyses to estimate the contribution of HRQOL information of each scale relative to that of others were conducted. The 171-item questionnaire could be completed by out-patients with epilepsy with good data quality. With few exceptions, generic and epilepsy-specific measures satisfied psychometric tests of hypothesized item groupings and scale score reliability (internal consistency and test-retest reliability) and differentiated well between groups of patients differing in time since last seizure and in symptom impact, regardless of time since last seizure. However, scales differed widely in their validity in discriminating between groups of patients known to differ clinically. The SF-36 Role Physical scale best discriminated among groups differing in disease severity. The epilepsy-specific Mastery, Impact, Experience, Worry, Distress, and Agitation scales were among the 10 best measures in discriminating among groups differing in disease severity. Generic measures, especially measures of social and role functioning and mental health, were best at differentiating groups of patients differenting in symptom impact. Recommendations are offered for concepts and specific scales most likely to be useful in future studies of the HRQOL burden of epilepsy and the HRQOL benefits of AED therapy.