Quality of Life in End-Stage Renal Disease Patients Undergoing Maintenance Hemodialysis: from Mesaurement to Implication
Date Issued
2006
Date
2006
Author(s)
Yang, Shu-Chang
DOI
en-US
Abstract
The thesis was comprised of three main papers and some related papers. In the first paper, we developed the dialysis module of the brief form of “World Health Organization Quality-of –Life Questionnaire Taiwan Version” [WHOQOL-BREF(TW)] and assessed its psychometric properties including reliability, validity, and sensitivity in patients undergoing regular hemodialysis (HD). QOL survey was administered to 283 regular HD patients in metropolitan Taipei. Instruments used included (1) the proposed module: composed of the core part, the WHOQOL-BREF(TW), and the six specific items; (2) the symptom/problem (S/P) scale: composed of 12 items specific for dialysis patients; (3) utility measurement which was performed with standard gamble (SG) method; and (4) rating scale (RS). Based on the 6 criteria of validity, reliability, and variance of the items, 4 HD-specific items were selected. Reliability study showed that the Cronbach’s alphas, composite reliability, and test-retest reliability (intraclass correlation at average 4-8 weeks retest interval) of the four domains, physical, psychological, social relationship, and environment, ranged from 0.74-0.82, 0.79-0.84, and 0.61-0.79, respectively. Validity study showed that all the correlations between an item and its corresponding domain were highly significant (r>0.4, p <0.01) and larger than the correlations between the item and other domains. SG and psychometric measures showed relatively low correlations (0.12-0.26). The module showed the same construct as the WHOQOL-BREF(TW) under confirmatory factor analysis, whereas the exploratory factor analysis showed mild variation. Convergent and discriminant validity were good. Global QOL, physical, psychological, and environment domains had some sensitivity to differentiate the severity of the condition of patients receiving HD. Clinical validity was demonstrated in global QOL, physical, and psychological domains to have significant correlations with S/P scores. We concluded that besides broader coverage than the core WHOQOL-BREF(TW), the dialysis module of the WHOQOL-BREF(TW) is a valid, reliable and sensitive QOL instrument for the assessment of HD patients in Taiwan.
In the second paper, We administered again WHOQOL-BREF(TW) and symptom/problem scale to 376 end-stage renal disease patients on regular hemodialysis in Metropolitan Taipei and Kee-lung City. WHOQOL-BREF(TW) was reliable and valid from various validation studies. Reliability and validity of WHOQOL-BREF(TW) in HD patients were verified and compared with those in a sample of general population of Taiwan. All four domains (physical, psychological, social, and environment) and global items (overall quality of life and general health) of WHOQOL-BREF(TW) each differentiated symptom/problems of HD patients from age-, gender-, and education-matched healthy referents. All four domains except environment and global items of WHOQOL-BREF(TW) each differentiated erythropoietin dosage from age-, gender-, and education-matched healthy referents. Analysis with multiple stepwise regressions was conducted to study determinants of QOL domains and items. After adjusting age, gender, marriage and education, the prominent associated factors of various QOL domains and items were age, area (Taipei or Keelung), hemoglobin level, normalized protein catabolic rate (nPCR); and symptom/problem scale. We concluded that the WHOQOL-BREF (TW) is reliable and valid for long term study of HD patients, and HD had negative impacts on QOL, especially in more severe patients with greater symptom/problems scores, lower hemoglobin levels, and lower nPCR values.
In the third paper, we applied the QOL to form a composite outcome indicator- “quality-adjusted life expectancy” in maintenance hemodialysis (MHD) patients. The objective of this study was to determine the cost of maintenance hemodialysis (MHD), including loss of healthy life expectancy and lifetime financial burden to the NHI (National Health Insurance) in Taiwan. Survival data were collected from 746 consecutive patients on MHD in Keelung-ChangGung Memorial Hospital from 1996 to 2003. The health expenditure data were collected from reimbursement file of National Health Insurance (NHI) in 2002 and 2003.The survival function was estimated and extrapolated throughout lifetime based on logit transform of survival ratio between the patients’ cohort and age-, gender-matched general population from vital statistics. The quality-of-life (QOL) data of MHD patients were measured by standard gamble (SG) and rating scale (RS) methods, which were integrated with survival to estimate quality-adjusted life expectancy (QALE). The QOL of general population was assumed as one. The results showed that life expectancy in MHD patients was 141.3±27.1 months (mean±standard deviation) with an expected loss of 111 months. After adjusted for QOL, the QALE were 113.3±19.8 and 80.2±15.7 quality-adjusted life months, respectively for SG and RS measurements, while those of loss of healthy life expectancy were 139.6±19.8 and 172.3 ±15.7 months, respectively. Estimated lifetime financial burden for a case of MHD were 143,307 and 144,715 USD in 2002 and 2003, respectively, while the corresponding incremental cost per quality-adjusted life years (QALY) for SG method would be 15,178 and 15,327 USD. The estimation based on extrapolation of survival and integration with QOL can be used as bench mark values for financial planning and comparative outcome evaluation of health services in the future.
Subjects
末期腎病
血液透析
生活品質
世界衛生組織生活品質問卷
透析模組
決定因素
校度
信度
敏感度
品質調整後存活
品質調整後存活預期
健康存活預期損失
健康預期
健康差距
end-stage renal disease
hemodialysis
quality of life
WHOQOL
WHOQOL-BREF(TW)
dialysis module
determinants
validity
reliability
sensitivity
quality-adjusted survival
quality-adjusted life expectancy
loss of healthy life expectancy
health expectancy
health gap
SDGs
Type
thesis
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