Nephrol Dial Transplant (1996) 11 [Suppl 2]: 125-129

Nephrology Dialysis Transplantation

Quality of life in dialysis patients. A Spanish multicentre study F. Moreno1, J. M. Lopez Gomez2, D. Sanz-Guajardo3, R. Jofre2, F. Valderrabano2, on behalf of the Spanish Cooperative Renal Patients Quality of Life Study Group4 'Department of Nephrology, Hospital Universitario Principe de Asturias, Alcala de Henares, Madrid, 2Hospital General Universitario Gregorio Marafi6n, Madrid, and 3Hospital Puerta de Hierro, Madrid, Spain "•Participating nephrologists in alphabetical order: Aguado S., Ajenjo E., Albert E., Ahnaraz M.A., Alvaro F., Antonio J., Arias M., Ayala J.A., Berdud I., Betriu A., Candell M., Cereza S., Coronel F., Detoro R., Fernandez G., Fort J., Gago E., Garcia C , Garcia F., Garcia H., Gard J.E., Garcia-Trio, Gas J.M., Gil A., Gomez L., G6mez-Martino J.R., Gonzalez I., Gonzalez L., Gorriz J.L., Gutierrez J.A., Hernandez J., Hernandez E., Hernandez G., Herrera J., Huarte E., Jarillo D., Jofre R., Lavilla J., Logroflo J.M., Lopez J.M., Lopez R., Lozano L., Llopis A., Madrigal J., Maduell F., Mallafre J.M., Marigliano N., Martin M.J., Martinez F., Martinez J., Mateos J., Mendiluce A., Miguel J.L., Moll R., Montoliu J., Moreno F., Naranjo J., Navas A., Oliva J.A., Olivares J., Parra E., Payan J., Pedraza A., Pelaez E., Peral V., Pereira A., Perez J., Perez V., Piera LI., Praga M., Purroy A., Rocha J.L., Rodriguez D., Roma E., Ruiz A., Saavedra J., San Martin A., Sanchez C., Sanchez R., Sancho J., Santiago G, Sanz C, Sanz-Guarjardo D., Selgas R., Sierra T., Suria M., Torres G., Valderrabano F., Valverde V., Vazquez M.I., Villaverde M.T., Virto R.

Abstract. The aim of this study was to evaluate the quality of life in patients on chronic dialysis and to research the influence of various factors related to treatment and ESRD on quality of life. The crosssectional study was carried out nationally and 1013 randomly selected stable patients on dialysis were evaluated. The evaluation of quality of life was by the Karnofsky Scale (KS) and the Sickness Impact Profile (SIP). Both questionnaires were self-reported. Comorbidity was evaluated according to the Friedman Comorbidity Index. Adjusted quality of life scores for case-mix differences of several groups of patients were compared. Twenty-six per cent of the patients showed severe quality of life restriction on the Global Score of SIP (score 5=20) and 31% on the KS (score ^60). The partial categories of the SIP that were more affected were work, recreation and pastimes, home management, and sleep and rest. No significant differences were found relating to dialysis technique, dialysis solution, or dialyser membrane. Greater haemoglobin concentrations were related to better quality of life scores on Physical Dimension and Global Score of SIP. Advanced age and Comorbidity Index were related to worse quality of life scores. We conclude that 25% of the patients showed an important effect of the disease on their quality of life. An increase in haemoglobin was related to better quality of life in dialysis patients. Advanced age and co-morbidity both adversely affected quality of life.

Key words: anaemia; co-morbidity; erythropoietin; haemoglobin; quality of life; chronic renal failure

Introduction

The present objectives for treatment of end-stage renal disease (ESRD) are 2-fold: in the first place to increase patient survival and in the second place to improve the quality of life of that survival. In order to improve the quality of life, it is essential to properly control the symptoms and complications of ESRD and work towards the full rehabilitation of the renal patient. Therefore, 'quality control' of medical care for these patients must be focused towards reaching these objectives. In this context, the evaluation of quality of life of the renal patient becomes an indispensable instrument in proving the effectiveness of therapeutic innovations, and in detecting those areas related to ESRD in which therapeutic effort, research or social support is most necessary. Over the past few years the therapeutic possibilities in the area of dialysis have changed greatly in, for example, the correction of anaemia with erythropoeitin (EPO), the general use of bicarbonate in dialysate, the more liberal use of special dialyser membranes, treatment with high doses of calcitriol to correct the severe hyperparathyroidism secondary to ESRD, or improvements made in continuous ambulatory peritoneal dialysis. These factors have probably had a positive Correspondence and offprint requests to: F. Moreno Barrio, Hospitalinfluence on the quality of life of patients on dialysis, Universitario Principe de Asturias, Seccion de Nefrologia, Carretera but extensive studies in which adequate indicators are Alcala-Meco S/N (Campus Universitario), Alcala de Henares, used are needed to evaluate both the evolution of 28805-Madrid, Spain © 1996 European Dialysis and Transplant Association-European Renal Association

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quality of life in patients on dialysis over time, and the influence of therapeutic changes and other factors on patient quality of life. The aim of the present study was to learn about the quality of life in patients receiving dialysis treatment in Spain today and to evaluate the impact of such factors as the ageing of the dialysis population, the co-morbidity associated with renal insufficiency, the correction of anaemia with EPO, dialysis technique or the almost general use of bicarbonate in dialysis solution. This is the first study of its kind to be carried out in Spain. Subjects and methods Patients To attain these objectives, a cross-sectional, multi-centre national study was carried out under the auspices of the Spanish Nephrology Society. Patients studied were from a random sample of 1188 patients on dialysis at 42 hospital centres. Firstly, a representative sample of hospitals all over the country was selected. Then each centre was assigned its corresponding fraction of the sample group. Finally, each centre randomly chose the patients to be studied from among the patients on dialysis in the hospital centre, those who were dialysed in surrounding dialysis clinics, those on home haemodialysis and those on ambulatory peritoneal dialysis. Patients had to meet the following conditions to be included in the study: patients with chronic renal failure on dialysis, aged greater than 15, with absence of vascular access problems, and at least 3 months since the start of dialysis treatment and on the same dialysis technique (the same dialysate and dialyser if on haemodialysis, and the same modality if on peritoneal dialysis), if on EPO at least 3 months on the treatment, and finally, at least 3 months since the last major complication (hospitalization of 7 days or more or with defined consequences). Data collection was done between June and December of 1993. Of the 1188 patients selected, 1023 returned the questionnaires. Ten were excluded because of improperly completed questionnaires. The final study was done on a total of 1013 cases. Evaluation of quality of life Two questionnaires were used to evaluate quality of life: the Karnofsky Performance Scale (KS) and the Sickness Impact Profile (SIP). Both were completed by the patients themselves at home. The KS is a global indicator of self-sufficiency and functional capacity [1]. It consists of a scale of 10 levels, with scores ranging from 100 (normal, without limitations) to 10 (moribund). A higher score indicates a greater quality of life. The SIP is a questionnaire based on behaviour which evaluates dysfunctional behavior related to the illness [2]. It is a non-pathology-specific indicator. It consists of 136 items, grouped into 12 activity categories in which dysfunctional behaviour can occur. The items are given values according to their relative importance. The 12 categories are grouped to obtain physical and psychosocial dimensions and a global SIP score. Scores range from 0 points (absence of dysfunction) to 100 points (presence of all possible dysfunctional behaviour in a category or group of categories). A lower

score, therefore, indicates a greater quality of life. For this study, the Spanish version of the SIP, developed by Dr F. Moreno, was used, adapted from the 'Spanish' version by W. Hendricson [3] to our environment. Other determinations Other aspects registered were those referring to dialysis technique, previous failed renal transplant, and treatment with EPO. Co-morbidity was evaluated using the Friedman co-morbidity index [4] and the presence of diabetes mellitus, blindness and intermittent claudication were registered. In calculating the co-morbidity index, 13 pathology groups are evaluated on a four level scale of severity (0: absent; 1: mild; 2: moderate; 3: serious); and points for all the groups are added. Occupational situation, social class and educational level were also registered. Analytic data included figures for haemoglobin, haematocrit, blood urea nitrogen (BUN), creatinine, Kt/V and PCR. Statistical study The comparisons of scores on the different quality of life indicators for the various groups of patients were done comparing the adjusted scores for the different groups through co-variance analysis. The co-variables used to make the casemix adjustments were age, co-morbidity index, presence of diabetes, gender, socio-economic level, educational level and haemoglobin. The study of the factors independently related to quality of life indicator scores was done by stepwise linear regression; among the variables whose influence was studied were personal characteristics, socioeconomic and educational level, co-morbidity, type of substirutive therapy, haemoglobin, Kt/V, PCR, previous failed transplant, time on dialysis, type of dialysis centre, type of dialyser membrane, dialysis solution and treatment with EPO. Logarithmic transformation (Ln) was used in the multivariable analyses of the quality of life indicator scores. Four outliers were excluded in the multivariable analyses. All significance contrasts are two-tailed.

Results Patient characteristics The main patient characteristics are shown in Table 1. Median age was 56 years (percentile 25: 42 years; percentile 75: 65 years). Forty-one per cent were 60 years of age or older. Fifty-six per cent were males and 44% females. Eight per cent were diabetics. Dialysis technique applied was in-centre haemodialysis for 88%, home haemodialysis for 0.7%; 7% received haemodiafiltration and 4% peritoneal dialysis. Seventythree per cent received EPO treatment. Mean haematocrit was 30% and 12% had a haematocrit of less than 25%. Of the patients on haemodialysis, 66% were dialysed with bicarbonate and 32% were using synthetic membrane. Evaluation of quality of life in patients on dialysis The general results of the quality of life indicators are shown in Table 2. The median of the quality of life indicators used indicates moderate impairment.

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Table 1. General characteristics of patients studied

Age (years) Time on renal substitutive therapy (years) Haemoglobin (g/dl) Co-morbidity index* Socio-economic index2 Academic index3

Mean

SD

Median

53 5.7

15 4.6

56 4.5

10 4.6 1.8 2.9 1.1 1.1

1.6 3.2 0.5 0.9 0.29 0.28

10 4 2 3 1.1 1

Influence of age on quality of life in patients on dialysis To test the influence of age, the patients were divided into three groups (70 years). On all the quality of life indicators used, age showed an important relation to quality of life, with older patients showing less functional capacity and greater effect of the disease on quality of life.

Influence of co-morbidity on quality of life in patients on dialysis PCR Quality of life indicator scores were compared, group1 ing the patients by the Friedman co-morbidity index See description in the text. Range 0-18. 2 into three groups ( 12). A strong relation1: low; 2: medium; 3: high. 3 level of studies completed: 1: illiterate; 2: can only read and write; ship was found between co-morbidity and the adjusted 3: primary studies; 4: high school; 5: university studies. scores on all indicators used, showing patients with a 4 Patients on haemodialysis. higher co-morbidity index as having a lower quality of life in all cases. Figure 1 shows the relation between Twenty-six per cent of the patients scored ^20 on the the co-morbidity index and the physical dimension and Global SIP and 31% scored