Fluid intake adherence and its associated factors in patients receiving maintenance hemodialysis: a cross-sectional study utilizing the COM-B model

For millions of people around the world, the kidneys have stopped working. When this happens, the body cannot filter out waste or balance fluids on its own. To survive, these patients must undergo a treatment called maintenance hemodialysis, where a machine acts as an artificial kidney, cleaning the blood several times a week. While the machine handles the filtration, the patient must manage their own daily life, and one of the hardest tasks is controlling how much they drink. Because the body cannot get rid of extra water between treatments, drinking too much can lead to dangerous swelling, heart strain, and a higher risk of death. Doctors give strict limits on fluid intake, but for many, sticking to these limits feels impossible. The challenge is not just about willpower; it is about understanding the disease, having support from loved ones, and believing one can succeed.

A team of researchers in Chongqing, China, decided to look closely at why some patients follow these rules better than others. They turned to a framework known as the COM-B model, which suggests that for any behavior to happen, a person needs three things: the capability to do it, the opportunity to do it, and the motivation to do it. In this context, capability means knowing what to do, opportunity means having the right environment and help, and motivation means wanting to do it. The researchers wanted to see how these three elements played out in the daily lives of dialysis patients, specifically regarding their fluid intake. They did not just ask if patients were following the rules; they asked what factors helped or hindered them, hoping to find a clear path to better health.

The study took place over three months in 2026 at a major hospital in Chongqing. The researchers invited 411 adults who had been receiving regular dialysis for at least three months to participate. These patients filled out a series of questionnaires while they were connected to their dialysis machines. The surveys asked about their daily habits, their knowledge of kidney disease, how much support they felt from their families, and how confident they felt about managing their own health. They also answered specific questions about how well they stuck to their fluid limits. The researchers then used statistical tools to connect the dots between these different pieces of information, looking for patterns that explained who was succeeding and who was struggling.

The results painted a picture of moderate success mixed with significant room for improvement. On average, the patients scored a 18.57 out of a possible 30 on a scale measuring how well they followed fluid restrictions. This indicated that while many were trying, the majority were not fully meeting the recommended limits. The analysis revealed that three main factors were strongly linked to better adherence. First, patients who knew more about their condition and how dialysis worked were better at controlling their drinking. Second, those who felt supported by their families were more successful. Third, patients who believed in their own ability to manage their disease, a quality known as self-efficacy, were the most consistent.

The study also uncovered specific groups that faced greater challenges. Patients who were obese found it harder to stick to fluid limits, as did those who received dialysis fewer than three times a week. These findings suggest that the physical body and the treatment schedule play a real role in how well a patient can follow medical advice. The researchers found that knowledge and family support did not just help patients directly; they also worked by boosting the patient's confidence. When a patient understood their disease and felt loved and encouraged by their family, their belief in their own ability to manage the condition grew, and that belief was a powerful driver for sticking to the rules.

This research suggests that helping patients drink the right amount of water requires more than just giving them a list of rules. It points to a need for a three-pronged approach. Doctors and nurses should focus on teaching patients clearly about their disease to build capability. They should encourage families to get involved, offering companionship and gentle reminders to create a supportive environment. Finally, they must work to build the patient's confidence, helping them feel capable of handling the daily challenge of fluid management. By addressing the mind, the social circle, and the knowledge base together, healthcare providers may be able to help patients navigate the difficult path of living with kidney failure more safely and effectively.