OBJECTIVES We investigated the validity of the dipstick method (Mossman Associates Inc. USA) and the expired CO method to distinguish between smokers and nonsmokers. We also elucidated the related factors of the two methods. METHODS: This study included 244 smokers and 50 exsmokers, recruited from smoking cessation clinics at 4 local public health centers, who had quit for over 4 weeks. We calculated the sensitivity, specificity and Kappa coefficient of each method for validity. We obtained ROC curve, predictive value and agreement to determine the cutoff of expired air CO method. Finally, we elucidated the related factors and compared their effect powers using the standardized regression coefficient. RESULTS: The dipstick method showed a sensitivity of 92.6%, specificity of 96.0% and Kappa coefficient of 0.79. The best cutoff value to distinguish smokers was 5-6ppm. At 5 ppm, the expired CO method showed a sensitivity of 94.3%, specificity of 82.0% and Kappa coefficient of 0.73. And at 6 ppm, sensitivity, specificity and Kappa coefficient were 88.5%, 86.0% and 0.64, respectively. Therefore, the dipstick method had higher sensitivity and specificity than the expired CO method. The dipstick and expired CO methods were significantly increased with increasing smoking amount. With longer time since the last smoking, expired CO showed a rapid decrease after 4 hours, whereas the dipstick method showed relatively stable levels for more than 4 hours. CONCLUSIONS: The dipstick and expired CO methods were both good indicators for assessing smoking status. However, the former showed higher sensitivity and specificity and stable levels over longer hours after smoking, compared to the expired CO method.
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OBJECTIVES To develop a physical functioning instrument for older adults living in the community. METHODS: A representative sample of 979 people aged 65 years or over were interviewed in-person. Of these, 199 people also completed a detailed in-hospital examination. The scale items were selected based on the frequency of endorsement, along with the item-total and inter-item correlations. The associations of the scale with their physical performance and clinical examination were analyzed to evaluate the criterion-related validity. Construct validity was assessed using factor analysis, and internal consistency through Cronbach's alpha and item-total correlations. Test-retest reliability was measured by agreement between the household survey and the repeat survey at the in-hospital examination. RESUJLTS: Initially, 23 items on the level of difficulty, ranging from no difficulty to an inability to complete a task, with the specific mobility and self-care tasks were included. Those with a high frequency of endorsement and a low inter-item or item-total correlations were excluded, resulting in a 10-item Physical Functioning (PF) scale. Equal weights were given to each item and a summated score was calculated. Significant associations were found between the PF scores and the physical performance, survey and clinical data. The scale revealed a 2-factor (mobility and self-care) structure. Cronbach's alpha was 0.92 and the item-total correlations were in the 0.63 to 0.78 range. Pearson's correlations for the test-retest ranged between 0.56 and 0.61. CONCLUSIONS: The newly developed Physical Functioning (PF) scale showed good psychometric properties in older people. Further work, however, is needed to improve its sensitivity to discriminate higher levels of functioning, in addition to assessing its predictive value in detecting changes in health.
It is a well known fact that obesity is an important cause of cardiovascular disease, emphasized by many studies. Recently, cardiovascular diseaase has been found to correlate not only to the extent of obesity, but also the fat distribution of the individual; especially, focusing on obesity of the abdomen. Unfortunately, the proposed indices for abdominal obesity are numerous, and the results vary according to the index chosen. Three-hundred and twelve bus drivers in November, 1995, were chosen as subjects of this study. The author chose to measure serum lipid levels, fasting blood sugar levels and blood pressure, that are thought to be important risk factors of cardiovascular diseases. Obesity indices were calculated using anthropometric measurements. We were able to evaluate the significance of obesity indices by examining correlations between these indices and the risk factors of cardiovascular disease. The results obtained were as follows: 1. The abdominal obesity indices and risk factors of cardiovascular disease, the levels of total cholesterol in the serum, fasting blood sugar levels, and diastolic blood pressure, increased significantly according to age. 2. There was a significant difference in the abdominal obesity indices according to drinking and smoking habits controlled for age. Among the risk factors of cardiovascular disease, triglyceride and diastolic pressures had significant differences according to the presence or absence of a drinking history controlled for age. 3. Although all obesity indices showed significant correlations, the weakest correlation was between BMI and abdominal diameter index and the strongest correlation was between sagittal diameter and sagittal diameter matched for height. 4. There was a negative correlation between HDL-cholesterol and obesity indices. The weakest correlation was between fasting blood sugar levels and both SD and SDH showed correlations with the risk factors. 5. There was a significant correlation between SD and total cholesterol in the serum and fasting blood sugars controlled for age, drinking, and BMI. 6. After categorizing the subjects into 2 separate age groups at the 40 year mark, in the less than 40 year old age group, controlled for drinking and BMI, the results of comparitive studies have shown correlations between total cholesterol serum levels and waist-hip ratio, conicity-index, and SD. There were correlations between fasting blood sugar levels and SD, ADI, and SDH. There were no correlations between obesity indices and both total cholesterol serum levels and fasting blood sugar levels in the greater than 40 year old age group. There were significant correlations between abdominal obesity indices and total serum cholesterol or fasting blood sugar levels in the less than 40 year old age group, but no correlations in the age group over 40. These correlated factors between abdominal obesity and cardiovascular disease are assumed to exist in Korea as well. Furthermore, in this study a high correlation was found between SD, SDH and the risk factors of cardiovascular disease. Even when controlled for age, drinking, smoking, and BMI, the correlations between risk factors of cardiovascular disease and these indices exist. Therefore, the obesity indices, SD and SDH may prove to be important prognostic indicators or risk factors of cardiovascular disease
In order to test scaling assumption, and to assess the validity, reliability, and acceptability of the Short Form 36(SF-36) health survey questionnaire, we conducted a survey. Samples were 296 workers who had been employed in small sized companies. All scale passed for item internal consistency(100% sucess rate) and item discriminant validity(100% success rate). Reliability coefficients were ranged from a low of 0.51 to a high of 0.85. For 87.5% of the total workers, inconsistent responses were not observed. Only 3.0% of the total workers failed two or more checks. Factor analysis was performed using principal axis factor method and quartimax rotation. In this survey, the SF-36 retained available psychometric properties even when used in a generally healthy worker group. But further study with some consideration to develope health status measurement is expected ; first, the definition of health status should be rationalized. Second, the measurement of outcome is an important consideration in evaluations of quality of care. But ambiguities hinder understanding of this important topic. Third, internal consistency should be interpreted with caution as an indication reliability because it ignores potentially important sources of variation that can occur over time.
With expanded and extended coverage of the national medical insurance and fast growing health care expenditures, appropriateness of health service utilization and quality of care are concerns of both health care providers and insurers as well as patients. An accurate patient classification system is a basic tool for effective health care policies and efficient health services management. A classification system applicable to Korean medical information-Korean Diagnosis Related Groups (K-DRGs)-was developed based on the U. S. Refined DRGs, and the performance of the developed system was assessed in this study. In the process of the development, first the Korean coding systems for diagnoses and procedures were converted to the systems used in the definition of the U. S. Refined DRGs using the mapping tables formulated by physician panels. Then physician panels reviewed the group definition, and identified medical practice patterns different in two countries. The definition was modified for the difference in K-DRGs. The process resulted in 1,199 groups in the system. Several groups in Refined DRGs could not be differentiated in K-DRGs due to insufficient medical information, and several groups could not be defined due to procedures which were not practiced in Korea. However, the classification structure of Refined DRGs was retained in K-DRGs. The developed system was evaluated for its performance in explaining variations in resource use as measured by charges and length of stay(LOS), for both all and non-extreme discharges. The data base used in this evaluation included 373,322 discharges which was a random sample of discharges reviewed ad payed by the medical insurance during the five-month period from September 1990. The proportion of variance in resource use which was reduced by classifying patients into K-DRGs-r-square-was comparable to the performance of the U. S. Refined DRGs: .39 for charges and .25 for LOS for all discharges, and .53 for charges and .31 for LOS for non-extreme discharges. Another measure analyzed to assess the performance was the coefficient of variation of charges within individual K-DRGs. A total of 966 K-DRGs (87.7%) showed a coefficient below 100%, and the highest coefficient among K-DRGs with more than 30 discharges was 159%.
OBJECTIVE To develop measurement scales of Internet addiction, and propose a Korean Internet Addiction Index (K-IAI) and classification criteria for Internet addiction from the threshold scores developed. METHODS: The identification of the concept of "Internet addiction" was based on the literature review. To select the scales, an exploratory factor analysis was applied. A construct validation was tested by a confirmatory factor analysis (CFA) with a structured equation model (SEM). In testing the validity of the classification criteria, ANOVA and non-recursive models with SEM were applied. RESULTS: Out of 1, 080 questionnaires distributed, 1, 037 were returned, ; a response rate of 96%. The Cronbach-alpha of all items was over 0.75. Using an exploratory factor analysis in the condition of a 6 factor constrain as the study model proposed, 23 of the initial 28 items were identified. In testing the discriminant and convergent validity of the selected 23 scales using CFA with SEM, the Internet addiction model explained about 93% of all variances of the data collected, and all the latent variables significantly explained the designated scales. A K-IAI was proposed using the T-scores of the sum of all factor averages. In the classification of users, the basic concept was a two standard deviation approach of the K-IAI as the criteria of MMPI. The addiction group had a score > or = 70 in the K-IAI, the pre-addiction group between > or = 50 and < 70, and the average user group < 50. The Internet use times of the classified groups were statistically different in the ANOVA and multiple comparisons. CONCLUSIONS: The K-IAI is a reliable and valid instrument for measuring Internet addiction. Moreover, the taxonomy of the groups was also verified using various methods.