The background to this thesis is the demand for a classification model to be able to determine the level of care of dialysis patients in the various dialysis centres in the Netherlands. The need for healthcare is growing because we are ageing, we can and want to do more, with technological developments that make it possible for us to live longer while the desired quality of care is increasing. These developments have led to an increase in healthcare costs over the decades, and they are still rising. Given the relatively high cost of nursing staff in dialysis departments, it is important to be able to regulate and control these expenditures. Appropriate staffing of nurses is also relevant for maintaining and improving the quality and safety of care. Not only financial resources are limited, also the (local) shortage of nursing staff forces managers of dialysis centres to strive for efficient staffing. Knowledge of the level of care of the patient and the time needed to provide the patient with the appropriate care, are preconditions for coordinating the accurate (daily) staffing of the department and staffing needs of the patients. A good classification model should offer that possibility, enabling the managers of the dialysis department to control costs and optimize patient care. In order to standardize the research, a "classification list" was conducted with relevant actions that can be measured in time and that have to be performed by nurses during dialysis treatment, supplemented by a number of patient characteristics. To guarantee an objective interpretation, the nurses used clear instructions. The time measurements (with a stopwatch) were performed by observers. During the years of this longitudinal study, time measurements were repeated and the results turned out not to be significantly different from the first measurements. In the Netherlands dialyses centres can be categorized in 4 main categories: centres in university hospitals, centres in general hospitals, independent centres with a nephrologist present, independent centres where a nephrologist visits weekly or is present on demand. The classification model proved satisfactory for both initial and follow-up measurements for three of the four categories of dialysis centre. In the dialysis centres in the university hospitals, however, the actual stopwatch-measured time exceeded the estimated time by the questionnaire. It turned out that the nurses in the university hospitals needed 10 minutes more time than the estimated time. Dialysis centres in university hospitals provide more complex care than other dialysis centres. One of the reasons is that these patients do not yet contribute to their own treatment and the (admitted) patients in the university centres are often too ill to actively participate in their own treatment. Further investigation showed that not only the above factors play a role in dialysis patients in university hospitals. The blood values of this patient group demonstrated that the albumin level is lower. In addition, we showed that hand grip strength of patients in university hospitals was also less. Altogether, these observations indicate that patients treated in university hospitals suffer from additional problems or illnesses than patients in the other hospital categories, that are not adequately captured by the classification list. Additional tests, such as the malnutrition inflammation score, may be used to further investigate this hypothesis In conclusion, we have succeeded in developing a classification model that can be used in three of the four categories of dialysis centres: dialysis centres in general hospitals, independent centres with a nephrologist present, and independent centres where a nephrologist visits weekly or is present on demand. For use in dialysis centres in university hospitals, the model must be further perfected.

De voortdurende verbeteringen in de gezondheidszorg dragen eraan bij dat de wereld- bevolking steeds ouder wordt. In Nederland bijvoorbeeld, met 17,4 miljoen inwoners, bedraagt het aandeel 65-plussers inmiddels 19,5% van de bevolking, waarbij 4,7% van de totale bevolking ouder is dan 80 jaar. De combinatie van een hoger aandeel ouderen en de hogere leeftijd die zij bereiken wordt wel dubbele vergrijzing genoemd [1].
Als gevolg van de vergrijzing van de bevolking en de vergaande nieuwe behan- delingsmogelijkheden en technologische ontwikkelingen neemt ook het aantal patiënten met een chronische ziekte toe, waarbij veel oudere patiënten meerdere ziektes of comorbiditeiten hebben.
Veel voorkomende chronische aandoeningen bij ouderen zijn hart- en vaatziekten [2] en diabetes. Nederland telde in 2019 1,5 miljoen mensen met een vorm van hart- en vaatziekten en 1,2 miljoen diabetespatiënten [3]. Deze ziekten, maar ook hyper- tensie en obesitas zijn risicofactoren voor schade aan de nieren, hersenen en andere organen [4]. Chronische nierschade is een veelvoorkomend gezondheidsprobleem met een prevalentie van ongeveer 10% in verschillende landen over de hele wereld, en is geassocieerd met verhoogde cardiovasculaire morbiditeit en mortaliteit, en met een lagere levensverwachting [2]. Chronische nierschade leidt vaak tot de noodzaak van nierfunctie vervangende therapie, hetzij niertransplantatie, peritoneale dialyse of chronische intermitterende hemodialyse [5]. In het algemeen wordt chronische intermitterende hemodialyse uitgevoerd op een dialyse-afdeling, in een kleine min- derheid als thuisdialyse.
Het aantal personen in Nederland dat afhankelijk is van nierfunctie vervangende behandeling neemt gestaag toe (figuur 1). Op 31 december 2019 betrof het ongeveer 18.000 patiënten [6].

Zie proefschrift voor de volledige samenvatting.