Journal of clinical epidemiology
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Indexes developed to measure physical functioning as an essential component of general health status are often based on sets of hierarchically-structured items intended to represent a broad underlying concept. Rasch Item Response Theory (IRT) provides a methodology to examine the hierarchical structure, unidimensionality, and reproducibility of item positions (calibrations) along a scale. ⋯ These findings support the content validity of the PF-10 as a measure of physical functioning and suggest that valid Rasch-IRT summary scores could be generated as an alternative to the current Likert summative scores. Unidimensionality and reproducibility of the item scale are essential prerequisites for the development of Rasch-based person measures of physical functioning that can be used across populations and over repeated tests.
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To analyze if patient selection bias could contribute to the improved prognosis reported for ventricular tachycardia (VT) and ventricular fibrillation (VF) when therapy is guided by electrophysiologic studies (EPS), we studied 90 consecutive patients admitted to a tertiary referral center with recent VT/VF who were candidates for EPS. Seventeen patients (19%) died during the initial hospital admission, and 30 (33%) died after discharge. Survival probability was 0.83 (95% confidence interval [CI], 0.74-0.90); 0.67 (95% CI, 0.56-0.75); and 0.53 (95% CI, 0.42-0.63) at 1 month, 1 year, and 3 years, respectively. ⋯ Thus, omission of these deaths in reports of EPS-guided therapy creates incomplete, biased cohorts. Furthermore, there may be a bias toward a healthier population among hospital survivors undergoing EPS. These findings may contribute to better outcomes in current series compared to historical controls.
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Randomized Controlled Trial Clinical Trial
Effects on response rates and costs of stamps vs business reply in a mail survey of physicians.
In the general population, the use of stamps rather than business reply postage significantly improves response rates in mail surveys. Among physicians, however, a smaller effect might be anticipated due to their greater sophistication. An experiment was conducted to test the hypothesis that stamps would improve response rates and lower costs in a physician survey that included intensive follow up. ⋯ Response rates, calculated as completed surveys divided by eligible physicians, were 83.8 and 72.1% for stamps and business reply respectively, a difference of 11.7 percentage points (p < 0.01). Moreover, the total cost per completed survey was $11.18 for the physicians receiving stamps and $14.25 for the physicians receiving business reply. As in mail surveys of the general public, the use of first-class stamps on return envelopes both improves response rates and reduces cost in surveys of physicians.
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Associations of indices of adiposity with cardiovascular risk factors were examined in 1860 middle aged men employed by the Western Electric Company in Chicago in 1960 and 1961. Body mass index and subscapular and triceps skinfolds were examined for associations with systolic and diastolic blood pressure, serum cholesterol, and post-load serum glucose. Correlations of study variables measured one year apart suggest that triceps and subscapular skinfold measurements are less reproducible than body mass index, but more reproducible than measurements of systolic and diastolic blood pressure and serum cholesterol. ⋯ This association was also independent of triceps skinfold and other variables. These analyses demonstrate positive associations of subscapular skinfold, an index of central adiposity, with blood pressure and serum glucose levels. Associations of subscapular and triceps skinfolds with serum cholesterol levels were not consistent in the cross-sectional and longitudinal analyses and require further investigation.
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During the past decade, the multidisciplinary pain clinic has become a popular alternative to the traditional treatment of persistent pain. There is, however, little information describing this population of health care users nor the impact this new demand has on utilization of health care services. The objectives of this study were three fold: to develop a profile of the characteristics of patients referred to a specialty pain clinic including their psychosocial adjustment to their condition; to identify predictors of the use of the specialty services; and to estimate the cost of health service utilization. ⋯ In addition, users of specialty pain clinic services generated proportionately less costs in the use of other health services when they were compared to non-users. The importance of social support and meaning of illness variables in predicting psychosocial adjustment to chronic pain is corroborated in this study as is the relevance of the pain clinic cognitive behavioural approach for these problems. In addition, compared to other chronic pain sufferers with similar characteristics, it appears that the use of the pain clinic contains the use of other services and thus has an important economic impact.