The outcome of therapy is the major concerning decision in selection of a treatment by patient and his or her physician. There are many studies in ESRD patients which are around the outcome of therapy; such as to improve the survival rate, decrease the hospitalization rate, ameliorate the quality of life, return to work or social activity or schooling (9,10,16,18). There are many subjects to evaluate the outcome of ESRD therapy; such as mortality, morbidity, quality of life and rehabilitation.
1. Mortality
The number of deaths in a year as a percentage of the mean of the number of ESRD patients at the beginning and end of the year is the crude mortality rate. It is not a good method for matching patients in different treatment due to individual variant, financial condition, social supports, and not all patients have died under analytic time. Kaplan-Meier (K-M) estimation is the most commonly used method to depict survival curves in ESRD patients [16, 25]. Time sequence in beginning of follow–up is depicted on the horizontal axis, and the percentage or probability of patients alive at a definite time is depicted on the vertical axis. Mortality is one of the most important and most commonly used methods to describe outcome for ESRD patients. USRDS points out that the adjusted one-year mortality rate of patients in United State is reduced gradually from 35-40% in 1985 to 22-25% in 2002 [26]. In 2001, there are 1019 (3%) patients on maintenance HD over 15 years, 10.2% patients between 10-15 years, and 24.6% patients between 5-10 years in
Taiwan [20].
The most important factors affecting mortality rate are age, race, cause of ESRD, pre-existing cardiac disease, gender, anemia, dialysis adequacy, co-morbidity [8,26].
The risk factors of mortality are smoking, neoplasm, malnutrition, and low serum albumin [8,26]. The leading causes of death in dialysis patients in Taiwan are cardiopulmonary system diseases (24.3%), and followed by infectious diseases (14.9%), neoplasm (4.6%), central nervous system diseases (4.5%), and gastrointestinal diseases (4.5%) [20].
Another complex method of survival analysis uses a multiple regression model, the most known of which is the Cox proportional hazards regression model. It is used to estimate the effects on mortality rate of different factors simultaneously or patients in different group [27]
.
2. Hospitalization
Hospitalization is one of the representatives of the healthy condition for ESRD patient. It is difficult to compare between countries because many factors such as culture, geographic differences, health insurance status, and political rules. It can be accumulated in hospitalization rate such as Point-prevalent sample or Period-prevalent sample over a year period, numbers of admissions, and length of hospital stay per year. A large-scale study in five European countries participating in the Dialysis Outcomes and Practice Pattern Study (DOPPS) reported that hospitalization rate was 0.99 per patient year and the mean length of hospital stay was 11 days. The major causes of hospitalization were cardiovascular-related diseases, vascular access-related diseases, infectious diseases, gastrointestinal diseases, and liver-related diseases [28].
Hospitalization data is reported annually in the USRDS, including times of
admissions and hospital days per year. Statistic data of hospitalization can be used to compare in diabetics and non-diabetics patients, HD and CAPD patients, and cause of ESRD and with treatment modality. In all age groups, the hospitalization rates for diabetics are higher than those for non-diabetics. The most common discharge diagnoses are cardiovascular diseases, infectious diseases, and gastrointestinal diseases [26].
3. Rehabilitation
Rehabilitation is a surrogate of the fundamental base of social life and ability to return to work or school. It has always been of concern in ESRD patients for going back to normal life as early as possible. The need of active patient participation is important to return functional activity. Psychologic support by family and friend can partially motivate the sense of controlling themselves health and desire of social activity. The rehabilitation of ESRD patients in Taiwan is household (23%), full time job (10.5%), part time job (6.7%), school (0.5%), unemployed (3.4%), self-care but need help (13.6%), and bed-ridden (11.5%) [20].
4. Quality of Life (QOL)
The World Health Organization (WHO) put forward a definition of quality of life (QOL) in 1993. It is defined as “ An individual’s perception of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards and concerns” [29]. In other word, QOL describes how well people feel about their life in many aspects as following:
physical, psychological, social, and economic.
In ESRD patients on dialysis therapy, better survival rate were ascribed to aggressive medical care, new technology, and social supports [30,31]. Now, the goal
of health care is not only to prolong the life or to ameliorate disease but also in improving the QOL. Therefore, QOL is the important indicator of the evaluation of therapy and health care.
QOL can be measured from many aspects with subjective indicators in field such as physical function, energy, psychological function, social activity, life satisfaction, sexual function, happiness, and individual values.
Objective assessments of QOL contain functional ability, employment status, and health status. For example, the ways to quantify a person’s ability to perform the test in observed variables such as muscle strength, speed of contraction and balance are good examinations in functional ability. The indicator which often used to estimate the functional ability of the ESRD patients is Karnofsky index. In Taiwan, the HD quality analysis in ESRD patients revealed that the Karnofsky score in most of patients are shown in Table 2-3 [20].
Employment is evaluated by employed or not under the condition of patient’s perception of himself or herself assessment with having ability to work.
Another objective measure is the established generic Sickness Impact Profile to assess health status of disability related with chronic illness [32]. It can be used to check a person’s ability to do daily work, such as shopping, housework, and to evaluate the change in memory and judgment behavior.
There are many subjective measures includes medical outcome study such as the World Health Organization Quality of life (WHOQOL) assessment instrument, Short Form-36 (SF-36) health survey, and the Kidney Disease Quality of life (KDQOL) instrument [29,33,34]. A total randomly selected sample size with 17236 HD patients in a cross-national prospective, observational study used KDQOL in 7 countries (USA, Japan, France, Germany, Italy, Spain, and the United Kingdom) revealed that QOL were highly related to risk of death and hospitalization in HD
patients under adjustment of demographic and co-morbid factors [35]. This large-scale study revealed that QOL was affected by socioeconomic factors (income, education, occupational status, and living status), treatment modal, laboratory factors, and co-morbidity factors. The living status, sleep especially affects QOL in ESRD patient on maintaining HD.