Min-Woo Jo

Comparing the psychometric properties of the EQ-5D-3L and EQ-5D-5L in cancer patients in Korea

PurposeThis study was conducted to assess the redistribution properties of the EQ-5D-3L when using the EQ-5D-5L and to compare the validity, informativity, and reliability of both EQ-5D-3L and EQ-5D-5L in Korean cancer patients.MethodsPatients visiting one ambulatory cancer center self-administered the two versions of the EQ-5D and the EORTC QLQ-C30 questionnaire. Redistribution properties in each dimension of EQ-5D were analyzed between EQ-5D-3L and EQ-5D-5L. Informativity was evaluated using the Shannon entropy and ceiling effect. Convergent validity was evaluated by comparing the EQ-VAS, ECOG performance status, and EORTC QLQ-C30 subscales. Reliability was also evaluated in terms of test–retest reliability.ResultsAll levels of the EQ-5D-3L substantially partitioned into associated levels of the EQ-5D-5L. The average inconsistency rate of the two versions was 3.5%. Absolute informativity was higher for the EQ-5D-5L than for the EQ-5D-3L, but their informative efficiency tended to be similar. The proportion of ‘perfect health’ (11111) decreased from 16.8% in the EQ-5D-3L to 9.7% in the EQ-5D-5L. EQ-5D-5L demonstrated similar or higher correlations with the EQ-VAS, ECOG performance status, and EORTC QLQ-C30, than the EQ-5D-3L. The intraclass correlation coefficient of the EQ-5D-5L index was 0.77.ConclusionsThe EQ-5D-5L had greater informativity and lower rate in the ceiling effect than those values of the EQ-5D-3L. The EQ-5D-5L showed good construct validity and reasonable reliability. Therefore, considering these findings, the EQ-5D-5L may be preferable to the EQ-5D-3L.

Estimating Quality Weights for EQ-5D Health States with the Time Trade-Off Method in South Korea

OBJECTIVE To estimate quality weights of EQ-5D health states with the time trade-off (TTO) method in the general population of South Korea. METHODS A total of 500 respondents valued 42 hypothetical EQ-5D health states using the TTO and visual analog scale. The quality weights for all EQ-5D health states were estimated by a random effects model and compared with those from studies in other countries. RESULTS Overall estimated quality weights for all EQ-5D health states from this study were highly correlated with those from previous studies, but quality weights of individual states were substantially different from those of their corresponding states in other studies. CONCLUSIONS The Korean value set differed from value sets from other countries. Special caution is needed when a value set from one country is applied to another with a different culture.

Mapping EORTC QLQ-C30 onto EQ-5D for the assessment of cancer patients

BackgroundThe European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30) is the instrument most frequently used to measure quality of life in cancer patients, whereas the EQ-5D is widely used to measure and evaluate general health status. Although the EORTC QLQ-C30 has been mapped to EQ-5D utilities, those studies were limited to patients with a single type of cancer. The present study aimed to develop a mapping relationship between the EORTC QLQ-C30 and EQ-5D-based utility values at the individual level.MethodsThe model was derived using patients with different types of cancer who were receiving chemotherapy. The external validation set comprised outpatients with colon cancer. Ordinary least squares regression was used to estimate the EQ-5D index from the EORTC QLQ-C30 results. The predictability, goodness of fit, and signs of the estimated coefficients of the model were assessed. Predictive ability was determined by calculating the mean absolute error, the estimated proportions with absolute errors > 0.05 and > 0.1, and the root-mean-squared error (RMSE).ResultsA model that included global health, physical, role, emotional functions, and pain was optimal, with a mean absolute error of 0.069 and an RMSE of 0.095 (normalized RMSE, 8.1%). The explanatory power of this model was 51.6%. The mean absolute error was higher for modeled patients in poor health.ConclusionsThis mapping algorithm enabled the EORTC QLQ-C30 to be converted to the EQ-5D utility index to assess cancer patients in Korea.

Daily collection of self-reporting sleep disturbance data via a smartphone app in breast cancer patients receiving chemotherapy: a feasibility study.

Background Improvements in mobile telecommunication technologies have enabled clinicians to collect patient-reported outcome (PRO) data more frequently, but there is as yet limited evidence regarding the frequency with which PRO data can be collected via smartphone applications (apps) in breast cancer patients receiving chemotherapy. Objective The primary objective of this study was to determine the feasibility of an app for sleep disturbance-related data collection from breast cancer patients receiving chemotherapy. A secondary objective was to identify the variables associated with better compliance in order to identify the optimal subgroups to include in future studies of smartphone-based interventions. Methods Between March 2013 and July 2013, patients who planned to receive neoadjuvant chemotherapy for breast cancer at Asan Medical Center who had access to a smartphone app were enrolled just before the start of their chemotherapy and asked to self-report their sleep patterns, anxiety severity, and mood status via a smartphone app on a daily basis during the 90-day study period. Push notifications were sent to participants daily at 9 am and 7 pm. Data regarding the patients’ demographics, interval from enrollment to first self-report, baseline Beck’s Depression Inventory (BDI) score, and health-related quality of life score (as assessed using the EuroQol Five Dimensional [EQ5D-3L] questionnaire) were collected to ascertain the factors associated with compliance with the self-reporting process. Results A total of 30 participants (mean age 45 years, SD 6; range 35-65 years) were analyzed in this study. In total, 2700 daily push notifications were sent to these 30 participants over the 90-day study period via their smartphones, resulting in the collection of 1215 self-reporting sleep-disturbance data items (overall compliance rate=45.0%, 1215/2700). The median value of individual patient-level reporting rates was 41.1% (range 6.7-95.6%). The longitudinal day-level compliance curve fell to 50.0% at day 34 and reached a nadir of 13.3% at day 90. The cumulative longitudinal compliance curve exhibited a steady decrease by about 50% at day 70 and continued to fall to 45% on day 90. Women without any form of employment exhibited the higher compliance rate. There was no association between any of the other patient characteristics (ie, demographics, and BDI and EQ5D-3L scores) and compliance. The mean individual patient-level reporting rate was higher for the subgroup with a 1-day lag time, defined as starting to self-report on the day immediately after enrollment, than for those with a lag of 2 or more days (51.6%, SD 24.0 and 29.6%, SD 25.3, respectively; P=.03). Conclusions The 90-day longitudinal collection of daily self-reporting sleep-disturbance data via a smartphone app was found to be feasible. Further research should focus on how to sustain compliance with this self-reporting for a longer time and select subpopulations with higher rates of compliance for mobile health care.

Rising rates, changing relationships: caesarean section and its correlates in South Korea, 1988–2000

Objective  To examine the trends in the relationship between caesarean section rates in South Korea and its correlates.

Measuring the burden of chronic diseases in Korea in 2007

OBJECTIVES This study was performed to measure the burden of disease from premature death and disability for chronic diseases in Korea in 2007. STUDY DESIGN Chronic diseases were defined using the WHO definitions. Disability-adjusted life years (DALY) were used to analyse insurance claim data. METHODS This was a population-based study and included the total population of Korea. DALYs were used to analyse insurance claim data. Years of life lost (YLL) and years lost to disability (YLD) were measured in terms of incidence rate and number of deaths. DALYs were aggregated to YLL and YLD. To ensure code validity, only patients who had visited a tertiary hospital or a clinic three or more times for the same disease were included. RESULTS Cerebrovascular disease was the leading contributor to the chronic disease burden, with a value of 907.4, followed by diabetes mellitus (899), ischaemic heart disease (710), cirrhosis of the liver (616.5), chronic obstructive pulmonary disease (512.9), asthma (503.1), hypertensive heart disease (407.5), stomach cancer (356) and peptic ulcer disease (292.5). As these results demonstrate, the highest ranked diseases were cardio-cerebrovascular or related diseases, as well as the fact that hypertension, diabetes mellitus and related complications, which are associated diseases, have became increasingly severe problems. And the rural areas have a higher burden of disease than metropolitan cities. According to difference in social status, Medicaid 2 group has more burden of disease than other groups. CONCLUSIONS It has been possible to present evidence regarding the burden of diseases and the relatively high risk of cardio-cerebrovascular disease. If the various types of cancer were combined and then the calculating tool applied, the burden would likely be greater than that of cardio-cerebrovascular disease. However, based on DALY, ischaemic heart disease demonstrated a remarkable increase compared to the rate in the previous study based on 2002 data. Underprivileged people in particular have been struggling - with chronic diseases.

Validity and reliability of the EQ-5D for cancer patients in Korea

PurposeThe purpose of this study was to assess the validity and reliability of the Korean version of the EQ-5D health questionnaire for use in patients with cancer in Korea.MethodsPatients with colorectal cancer were recruited from one ambulatory cancer center. Each participant consecutively self-administered the EQ-5D, the EORTC QLQ-C30, and the Short Form-36 (SF-36). Discriminatory ability was evaluated by comparing the SF-36 subscales with their corresponding EQ-5D dimensions. Convergent validity was assessed by examining the correlations between the EQ-5D index, EORTC QLQ-C30 subscales, and SF-36 scale and summary scores. Test-retest reliability was also evaluated.ResultsSubjects reporting problems in each EQ-5D dimension showed lower scores on all SF-36 subscales. As expected, the relationships were stronger between the EQ-5D functional dimensions and physical function on the EORTC QLQ-C30 and between the EQ-5D anxiety/depression dimension and emotional function on the EORTC QLQ-C30. The EQ-5D index and SF-36 scales were moderately or highly correlated. intraclass correlation coefficient of the EQ-5D index was 0.45.ConclusionsThe Korean version of the EQ-5D may be a valid tool for assessing the health-related quality of life of patients with cancer. However, further research is needed to determine the reliability of the Korean EQ-5D over different time intervals and disease conditions.

Cumulative Query Method for Influenza Surveillance Using Search Engine Data

Background Internet search queries have become an important data source in syndromic surveillance system. However, there is currently no syndromic surveillance system using Internet search query data in South Korea. Objectives The objective of this study was to examine correlations between our cumulative query method and national influenza surveillance data. Methods Our study was based on the local search engine, Daum (approximately 25% market share), and influenza-like illness (ILI) data from the Korea Centers for Disease Control and Prevention. A quota sampling survey was conducted with 200 participants to obtain popular queries. We divided the study period into two sets: Set 1 (the 2009/10 epidemiological year for development set 1 and 2010/11 for validation set 1) and Set 2 (2010/11 for development Set 2 and 2011/12 for validation Set 2). Pearson’s correlation coefficients were calculated between the Daum data and the ILI data for the development set. We selected the combined queries for which the correlation coefficients were .7 or higher and listed them in descending order. Then, we created a cumulative query method n representing the number of cumulative combined queries in descending order of the correlation coefficient. Results In validation set 1, 13 cumulative query methods were applied, and 8 had higher correlation coefficients (min=.916, max=.943) than that of the highest single combined query. Further, 11 of 13 cumulative query methods had an r value of ≥.7, but 4 of 13 combined queries had an r value of ≥.7. In validation set 2, 8 of 15 cumulative query methods showed higher correlation coefficients (min=.975, max=.987) than that of the highest single combined query. All 15 cumulative query methods had an r value of ≥.7, but 6 of 15 combined queries had an r value of ≥.7. Conclusions Cumulative query method showed relatively higher correlation with national influenza surveillance data than combined queries in the development and validation set.

Health-related quality of life in chronic obstructive pulmonary disease patients in Korea

BackgroundThere are few publications on quality measurement of COPD health state according to the severity level using EQ-5D in Korea. The present study aimed to evaluate the health-related quality of life (HRQoL) in patients with chronic obstructive pulmonary disease (COPD) in terms of disease severity in Korea.MethodsTotally two hundred patients with COPD were consecutively recruited in one tertiary hospital of Korea. Each respondent was asked to fill out the questionnaire through a face-to-face interview after providing informed consent. The questionnaire included general and clinical characteristics as well as the EQ-5D and Clinical COPD Questionnaire (CCQ). HRQoL was evaluated according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria and severity of breathlessness.ResultsThe adjusted mean EQ-5D index scores were 0.83, 0.88, 0.81 and 0.60 in stage I, II, III and IV, respectively. The EQ-5D index tended to decrease with GOLD criteria. The adjusted mean EQ-Visual Analog Scale (VAS) scores ranged from 65.1 in stage IV to 73.9 in stage I. The CCQ total scores deteriorated with an increasing GOLD stage and severity of breathlessness (all P < 0.001). The correlation between CCQ total score and EQ-5D index was −0.69.ConclusionsOur study shows that HRQoL in COPD measured by EQ-5D and CCQ worsens with the GOLD stage and severity of breathlessness. EQ-5D and CCQ could be useful instruments for an evaluation of HRQoL in COPD patients in Korea.

Estimating Quality-Adjusted Life-Year Loss Due to Noncommunicable Diseases in Korean Adults through to the Year 2040

OBJECTIVES To estimate the loss in quality-adjusted life-years (QALYs) in Korean adults due to 13 noncommunicable diseases (NCDs) in 2010 and predict changes in QALY loss through to the year 2040. METHODS Thirteen NCDs (hypertension, diabetes mellitus, hyperlipidemia, stroke, myocardial infarction, angina, arthritis, osteoporosis, asthma, allergic rhinitis, atopic dermatitis, cataract, and depression) were selected from the Korean Community Health Survey 2010. The EuroQol five-dimensional questionnaire index from the Korean Community Health Survey 2010 and the Korean valuation set were used to estimate utility weights according to sex, age, and disease. Morbidity data were also obtained from the Korean Community Health Survey 2010. Mortality data according to disease and life expectancy were retrieved from the Korean Statistical Information Service. To predict future QALY loss, future population projection data from the Korean Statistical Information Service were used as substitutes for 2010 population size. RESULTS Among the assessed 13 NCDs, the largest total QALY loss was for hypertension (513,113 QALYs; units are omitted hereafter), followed by arthritis (509,317) and stroke (431,049). The largest QALY loss due to mortality was stroke (306,733), whereas the largest QALY loss due to morbidity was arthritis (502,513). By applying the middle estimate of future population, the largest increase in total QALY loss between 2010 and 2040 was for hypertension (840,582), followed by stroke (719,076) and diabetes mellitus (474,607). CONCLUSIONS Hypertension, arthritis, and stroke are important in terms of total QALY loss, which will continuous to increase because of aging. These results could be used to develop cost-effective interventions that reduce the burden of NCDs.