Quality of life in dialysis patients. A Spanish multicentre study

Transcription

1 Nephrol Dial Transplant (1996) 11 [Suppl ]: Nephrology Dialysis Transplantation Quality of life in dialysis patients. A Spanish multicentre study F. Moreno 1, J. M. Lopez Gomez, D. Sanz-Guajardo 3, R. Jofre, F. Valderrabano, on behalf of the Spanish Cooperative Renal Patients Quality of Life Study Group 4 'Department of Nephrology, Hospital Universitario Principe de Asturias, Alcala de Henares, Madrid, Hospital General Universitario Gregorio Marafi6n, Madrid, and 3 Hospital 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 13 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. 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=0) 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 were related to worse quality of life scores. We conclude that 5% 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 -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, 8805-Madrid, Spain used are needed to evaluate both the evolution of 1996 European Dialysis and Transplant Association-European Renal Association

2 16 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 4 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, 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 Of the 1188 patients selected, 3 returned the questionnaires. Ten were excluded because of improperly completed questionnaires. The final study was done on a total of 13 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 levels, with scores ranging from 0 (normal, without limitations) to (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 []. It is a non-pathology-specific indicator. It consists of 136 items, grouped into 1 activity categories in which dysfunctional behaviour can occur. The items are given values according to their relative importance. The 1 categories are grouped to obtain physical and psychosocial dimensions and a global SIP score. Scores range from 0 points (absence of dysfunction) to 0 points (presence of all possible dysfunctional behaviour in a category or group of categories). A lower F. Moreno et al. 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; : 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 5: 4 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 1% had a haematocrit of less than 5%. Of the patients on haemodialysis, 66% were dialysed with bicarbonate and 3% 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. The median of the quality of life indicators used indicates moderate impairment.

3 Quality of life on dialysis Table 1. General characteristics of patients studied Age (years) Time on renal substitutive therapy (years) Haemoglobin (g/dl) Co-morbidity index* Socio-economic index Academic index 3 Kt/V PCR 4 Mean SD Median See description in the text. Range : low; : medium; 3: high. 3 level of studies completed: 1: illiterate; : can only read and write; 3: primary studies; 4: high school; 5: university studies. 4 Patients on haemodialysis. Twenty-six per cent of the patients scored ^0 on the Global SIP and 31% scored <60 on the KS; in both cases these scores indicate a significant effect of the disease on quality of life. The areas of the SIP in which patients on dialysis showed the greatest effect of the disease were 'work' (mean 8, SD 3), 'recreation and pastimes' (mean 0, SD ), 'home management' (mean 19, SD 3) and 'sleep and rest' (mean 0, SD 0). The percentage of patients with a score greater than 0 in these categories was: 'sleep and rest' 4%, 'home management' 34%, 'work' 4% and 'recreation and pastimes' 38%. Influence of dialysis technique on quality of life After adjusting the quality of life indicator scores for the casemix differences, no significant differences were found in relation to dialysis technique (conventional haemodialysis, haemodiafiltration, peritoneal dialysis), the type of dialysis solution (bicarbonate or acetate) nor between the synthetic or cellulose membranes. Since patients were not assigned dialysis techniques randomly, there is the possibility of the selective orientation of patients with a worse situation towards the use of special membranes and dialysing with bicarbonate, which could mask the beneficial effects these techniques may have on quality of life. No significant differences were found between different groups for Kt/Voi PCR. Higher socio-economic and educational level showed a significative relation to greater quality of life in most analyses. Table. Quality of life indicator score 1 Influence of age on quality of life in patients on dialysis 17 To test the influence of age, the patients were divided into three groups (<60, 60-69, >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 Quality of life indicator scores were compared, grouping the patients by the Friedman co-morbidity index into three groups (<6, 6-1, > 1). A strong relationship was found between co-morbidity and the adjusted scores on all indicators used, showing patients with a higher co-morbidity index as having a lower quality of life in all cases. Figure 1 shows the relation between the co-morbidity index and the physical dimension and global score of the SIP. Influence of haemoglobin on quality of life To investigate the relation between haemoglobin and quality of life, patients were divided into four groups according to their haemoglobin: <8, 8-, -1, > 1 g/dl (number of cases analysed 5, 385, 335 and 85, respectively). Scores of the four groups were compared through co-variance analysis, adjusting the scores for the differences of casemix in age, co-morbidity index, presence of diabetes mellitus, Ln Physical Dimension of SIP 3,5T ,5 _p< y,5 j*-\,5 1, ,5 <6 6-1 >1 Ln Global Score of SIP,0001 <6 6-1 >1 Fig. 1. Relation between Friedman's co-morbidity index and the physical dimension and global score of SIP. Mean adjusted scores and 95% confidence limits. A higher score indicates a lower quality of life. \ Mean SD Median Percentile 5 Percentile 75 Karnofsky Scale 1 Physical dimension of SIP Psychosocial dimension of SIP Global score of SIP Range 0- (higher score implies better performance). Range 0-0 (lower score implies less illness-related behavioural disfunction).

4 18,75,5,5 1,75 Ln Global Score of SIP I,05 4 I < >1 Hemoglobin g/dl Ln Physical Dimension of SIP,5-,,5 1,75 1,5 K I SI p< I <B >1 Hemoglobin g/dl Fig.. Relation of haemoglobin to SIP scores. Mean adjusted scores and 95% confidence interval. Lower scores imply a better quality of life. socio-economic level and educational level. Significant differences were found between the groups on the physical dimension of the SIP (P<0.01) and on the global score for the SIP (P<0.05), although no significant differences were found on the psychosocial dimension of the SIP or the KS. In Figure mean adjusted scores for the physical dimension and global scores on the SIP are shown. Factors independently related to quality of life Factors related negatively to quahty of life according to global score and the physical dimension of the SIP (Figure 3) were, first of all, co-morbidity and age, and secondly, the presence of diabetes mellitus and the female sex. Factors related to a greater quality of life GLOBAL SCORE OF SIP Age Educational level Diabetes Haematocrit Socio-economic level Female PHYSICAL SCORE OF SIP Age Diabetes Female Socio-economic level Haemoglobin Educational level Intermittent claudication Better QL [Worse QL mmm = -0, -0,1 0 0,1 0, 0,3 0,4 Standardized regression coefficients Bener QL WorseQL F Z -0, -0,1 0 0,1 0, 0,3 0,4 Standardized regression coefficients Fig. 3. Standardized regression coefficients. Standardized coefficient represents the relative influence from each variable on scores of quality of life indicators. Dependent variables: logarithmic transformation of quality of life indicators score. F. Moreno et al. according to the same indicators were educational level, socio-economic level and increased haemoglobin (R ln SIP global: 0.8; R ln physical dimension: 0.34). The standardized regression coefficients are shown as these coefficients represent the true influence of each variable on quality of life scores. Factors related negatively to quality of life on the psychosocial dimension of SIP were co-morbidity index, age and diabetes. Education has a high positive relation to quality of life on psychosocial dimension of SIP (R In psychosocial dimension: 0.). On the KS, the factors related to a lower quality of life were co-morbidity index, age, the presence of diabetes and of blindness. A higher socioeconomic level and higher educational level also related to a greater score on the KS (R ln KS: 0.31). Quality of life has not been shown to relate significantly in this analysis to Kt/V, PCR, dialysis technique or type of dialysis solution or dialyser membrane. Discussion The closest antecedents to this study can be found in studies done by the National Kidney Dialysis and Kidney Transplantation Study (NKDKTS) in the USA [5,6] in which the KS and SIP were used as quality of life indicators. The principal difference in methodology between the two studies is that the NKDKTS quality of life questionnaires were answered to an interviewer rather being self-reported by the patients as in the Spanish study. It has been proved that SIP scores are somewhat greater when the questions are self-reported than when answered to an interviewer and response reliability is higher []. Factors related to SIP scores were superimposed, the NKDKTS having also found that age, co-morbidity, diabetes and education were the variables most related to global SIP scores. This study did not contemplate the effect of haemoglobin on quality of life. Harris et al.[l] related co-morbidity, a lower educational level, and a lower socio-economic status to higher scores on the SIP (more dysfunction), in a study carried out on elderly patients with mild chronic renal insufficiency. In analysing the results of this study, it is important to remember that patients were not assigned to different dialysis techniques and the use of special membranes or bicarbonate solution randomly. Therefore the absence of differences in quality of life in patients on different dialysis techniques cannot be considered a definitive result. Nephrologists tend to use bicarbonate solution and special dialyser membranes on patients in poorer condition, and therefore, the selective orientation of more disabled patients towards these techniques can bias the results. The influence of anaemia correction on the quality of life of dialysis patients has been extensively proved in recent years [8-]. This study proves that even in the present dialysis population, in which the correction of anaemia with EPO is a habitual practice, and in spite of the fact that the differences in haemoglobin

5 Quality of life on dialysis were not large in most cases, there is still a direct relation between haemoglobin and quality of life, the quality of life tending to improve as haemoglobin increases. A previous study carried out on 71 quality of life determinations from patients on haemodialysis also showed a direct relation of haemoglobin with quality of life using the SIP and KS [11]. On the other hand, the confirmation of the differences in quality of life among patients on dialysis related to haemoglobin confirms assertions made by Nissenson [1], who has criticized the excessively low EPO doses generally used today, depriving patients of the full potential benefit of an increase in haematocrit. In the same vein, it is Eschbach's opinion [13] that partial anaemia correction, as it is generally seen in dialysis centres, inhibits the full potential benefit of EPO treatment. The instruments used to assess quality of life in this study have amply proved their efficiency and sensitivity for renal patients. The results found here contribute to confirming their usefulness with renal patients, since they have been able to discriminate between groups of patients regarding age, co-morbidity and haematocrit, as they exist in present clinical practice. As a final summary, it is important to emphasize that among the factors we have found which relate to the quality of life indicators used in this study, haemoglobin is probably the only one in which we have influence on improving the quality of life in patients on dialysis. Random, long-term studies are needed to determine if the variations in dialysis technique (type of dialyser membrane, dialysis solution, haemodiafiltration or dialysis duration) can influence patients' quality of life. It is also essential to reach an approximation of optimal haemoglobin and haematocrit for patients on dialysis; that is, the haemoglobin which provides maximum benefits physiologically, and in the welfare and self-sufficiency of patients with the minimum of adverse effects and an assumable cost. Finally, efforts to improve the quality of life in patients on dialysis must reach beyond strictly nephrological care. In this sense, it would be interesting to evaluate the effects other factors not analysed in this study, such as social and family support, individual psychological factors and physical, psychological and occupational 19 rehabilitation, have in influencing quality of life for the renal patient. Acknowledgements. This study was supported by grants from the P.E.N.S.A.-Esteve trust. References 1. Karnofsky DA, Burchenal JH. The clinical evaluation of chemotherapeutic agents in cancer. In: Macleod CM, ed. Evaluation of Chemotherapeutic Agents. New York Columbia University Press, New York, 1949: Bergner M, Bobbitt RA, Carter WB, Gilson BS. The Sickness Impact Profile: development and final revision of a health-status measure. Med Care 1981; 19: Hendricson WD, Russell IJ, Prihoda ThJ, Jacobson JM, Rogan A, Bishop GD. An approach to developing a valid Spanish language translation of a health-status questionnaire. Med Care 1989; 7: Friedman EA. Diabetic nephropathy. In: Suky WN, Massry SG, eds. Therapy of Renal Diseases and Related Disorders, nd edn. Kluwer Academic Publishers, Massachusetts, 1991: Hart LG, Evans RW. The functional status of ESRD patients as measured by the Sickness Impact Profile. J Chron Dis 1987; 40(Suppl 1): 117S-130S 6. Evans R, Manninen D, Garrison L et al. The quality of life of patients with end-stage renal disease. N Engl J Med 1985; 31: Harris L, Luft F, Rudy D, Tiemey W. Clinical correlates of functional status in patients with chronic renal insufficiency. Am J Kidney Dis 1993; 1: Evans RW, Rader B, Manninen DL and the Cooperative Multicenter EPO Clinical Trial Group. The quality of life of hemodialysis recipients treated with recombinant human erythropoietin. J Am Med Assoc 1990; 63: Canadian Erythropoietin Study Group. Association between recombinant human erythropoietin and quality of life and exercise capacity of patients receiving haemodialysis. Br Med J 1990; 300: Moreno F, Aracil J, Perez E, Valderrabano F. Improvement in the quality of life of haemodialysis patients treated with erythropoietin. A controlled study (abstract). Nephrol Dial Transplant 199; 7: Moreno F, Valderrabano F, Aracil FJ, Perez R. Influence of haematocrit on quality of life of haemodialysis patients (abstract). Nephrol Dial Transplant 1994; 9: Nissenson AR. National Cooperative rhu erythropoietin study in patients with chronic renal failure: a phase IV multicenter study. Report of National Cooperative rhu Erythropoietin Study Group. Am J Kidney Dis 1991; 18 (Suppl 1): Eschbach JW. Erythropoietin: the promise and the facts. Kidney Int 1994; 45 (Suppl 44): S70-S76