New 25-Item Scale Catches Hidden Malnutrition in China’s Kidney Patients

Chronic kidney disease quietly affects roughly one in ten adults worldwide, and in China the burden is even heavier, with national prevalence estimates reaching 13.2 percent of the adult population. Yet one of the most dangerous complications of failing kidneys is not the kidney damage itself but a slow, often invisible erosion of the body’s nutritional reserves. Malnutrition, frequently manifesting as protein-energy wasting with loss of muscle mass, declining physical function and unintentional weight loss, strikes between 11 and 54 percent of patients as kidney function falls through stages three to five, and can exceed half of all patients by the time dialysis becomes necessary. Now, a research team working between China and Malaysia has built and rigorously tested a new measurement instrument designed to expose exactly where patients’ nutritional understanding breaks down, offering clinicians a practical tool to intervene before the damage becomes irreversible.

The instrument, named the CKD-Malnutrition Knowledge, Attitude and Practice scale, or CKD-MKAP, was described in a study published in the journal Nursing Open. Its development followed a multiphase quantitative design grounded in the well-established KAP framework of behavioural change theory, which holds that accurate perceived knowledge fosters positive attitudes, which in turn translate into effective dietary practices. The team began by synthesising a comprehensive literature review of clinical nutrition guidelines for kidney disease with qualitative findings from previously published semi-structured interviews with thirteen Chinese patients who had experienced malnutrition. Those interviews explored what patients actually knew about malnutrition, how they perceived their own nutritional status, and what barriers and motivators shaped their eating habits. Mapping those lived experiences onto the three KAP domains produced an initial pool of thirty-eight candidate items covering everything from awareness of symptoms and risk factors to beliefs about diet therapy and concrete self-management behaviours such as regular weighing and protein intake.

Refining that raw item pool required the structured judgement of experts. The researchers convened a Delphi panel of fifteen specialists, including ten nephrology experts, three clinical nutrition specialists and two psychometricians, drawn from eight institutions across five regions in two countries. More than eighty percent of the panellists had over a decade of clinical or research experience. Across two email-based consultation rounds conducted between May and July 2023, response rates reached 89.5 percent and 93.75 percent respectively, and the calculated authority coefficient of 0.77 signalled a high degree of expert reliability. Items were evaluated using boundary value methods incorporating full-score frequency, arithmetic means and coefficients of variation, with predefined statistical thresholds determining survival. Eleven items fell during the Delphi phase, including questions about regional and religious food cultures and a query on whether oral supplements could replace ordinary food, leaving a preliminary twenty-seven-item scale.

Before formal validation, a pilot study with twenty kidney disease patients tested the draft instrument for clarity and acceptability. Every participant completed the questionnaire, reported that the items were clear and easy to understand, and finished in eight to fourteen minutes, with no revisions requested. The team then moved to the main psychometric evaluation, distributing 330 questionnaires and analysing 303 valid responses collected between July and November 2023. The sample was predominantly male at 63.7 percent, with a mean age of 48.26 years, and spanned the full range of kidney disease severity, from early-stage patients to the 32 percent already at stage five. Crucially, the sample was randomly split into two independent subsamples of 152 and 151 participants, one for exploratory factor analysis and one for confirmatory factor analysis, a cross-validation strategy designed to ensure that the scale’s structure would hold up beyond the data that shaped it.

The statistical machinery behind the validation was considerable. Content validity was assessed with item-level and scale-level content validity indices, and the results were striking: item-level values ranged from 0.93 to 1.00 across all three domains, comfortably above the accepted threshold of 0.83, while the scale-level average reached 0.99. For the dichotomous Perceived Knowledge domain, classical test theory came into play, with difficulty indices expected between 0.31 and 0.60 and discrimination indices above 0.20. Seven of the eight knowledge items performed well, but one item asking simply whether patients knew what malnutrition was showed suboptimal difficulty and discrimination and was deleted. Exploratory factor analysis, using principal-axis factoring with oblique rotation, extracted a single dominant factor for both the Attitude domain, explaining 69.87 percent of variance with a Kaiser-Meyer-Olkin value of 0.931, and the Practice domain, explaining 61.84 percent of variance, a clean structure that aligned precisely with the theoretical KAP framework.

Confirmatory factor analysis then put the emerging structure through a harsher test. Because the data violated assumptions of multivariate normality, the researchers applied the robust maximum likelihood estimator to the Attitude and Practice models and the weighted least squares mean and variance adjusted estimator to the categorical knowledge items. The initial knowledge model fit poorly, and one item asking about the relationship between malnutrition and chronic renal disease, with a factor loading of just 0.304, was removed, dramatically improving fit indices to a comparative fit index of 0.978 and a standardised root mean residual of 0.061. The attitude and practice models required theoretically justified post hoc correlations among residuals of conceptually related items, such as those concerning professional nutritional interventions, before achieving acceptable fit. The final attitude model reached a comparative fit index of 0.982 and the practice model 0.976, both well above the 0.90 benchmark, with root mean square error of approximation values of 0.077 and 0.071 respectively.

The finished instrument is deliberately lean: twenty-five items across three dimensions, scored separately rather than summed. The Perceived Knowledge domain contains six yes-or-no items yielding scores from zero to six, covering nutritional status awareness, symptoms, risk factors, consequences, daily protein requirements and prevention. The Attitude domain uses nine items on a five-point Likert scale from strong disagreement to strong agreement, spanning beliefs about the importance of nutrition, the value of optimism and self-control, and the role of diet therapy in treatment. The Practice domain asks patients how often they perform ten behaviours, from prioritising nutrition intake and measuring weight regularly to consuming high-quality protein and adhering to dietary recommendations, on a frequency scale from never to always. Reliability figures were strong, with Cronbach’s alpha values of 0.740 for knowledge, 0.970 for attitude and 0.958 for practice, and composite reliability estimates of 0.743, 0.968 and 0.957. Discriminant validity was confirmed through the Fornell-Larcker criterion, with the square roots of average variance extracted for each domain exceeding all inter-construct correlations, which ranged from 0.443 to 0.585.

The clinical logic of the scale is straightforward but powerful. Because many malnourished Chinese kidney patients receive inadequate nutritional education, a brief questionnaire that separates what patients know from what they believe and what they actually do allows nurses and physicians to pinpoint the weakest link. A patient with solid knowledge but poor practices, for example, may benefit far more from behavioural counselling than from another informational pamphlet. The researchers also compared their instrument against existing alternatives, noting that a recently developed seventy-seven-item nutritional KAP questionnaire for non-dialysis patients reported domain alpha values of 0.861, 0.816 and 0.612, whereas the twenty-five-item CKD-MKAP achieves comparable or superior reliability with far less respondent burden, an important consideration for busy wards and outpatient clinics.

The authors are candid about the limits of their work. The validation sample came from a single city in northwest China, raising questions about generalisability across the country’s enormous regional and cultural diversity. Test-retest reliability was not assessed, so temporal stability remains unknown, and the scale’s responsiveness to change has yet to be demonstrated, meaning it cannot yet be formally adopted as an outcome measure for evaluating educational interventions without further longitudinal psychometric testing. The post hoc residual correlations in the attitude and practice models, while theoretically justified, were not independently cross-validated and may hint at local dependence or hidden subdimensions that larger studies should investigate. No formal a priori power analysis was conducted, though the observed strong communalities and factor loadings compensate for the modest sample sizes.

Even with those caveats, the arrival of a culturally adapted, psychometrically validated malnutrition KAP scale fills a genuine gap. Previously available Chinese tools examined isolated KAP dimensions or lacked rigorous validation, while international scales carry assumptions shaped by foreign socioeconomic and dietary contexts that limit their applicability to Chinese patients, whose food culture, linguistic nuances and healthcare experiences differ substantially. By embedding items rooted in the actual reported experiences of Chinese patients and then subjecting them to Delphi consensus, item analysis, exploratory and confirmatory factor analysis, the team has produced an instrument that is short enough for routine clinical use yet statistically robust. If subsequent multicentre validation confirms its stability across regions, the CKD-MKAP could become a standard part of nursing assessments for kidney patients, turning the quiet epidemic of protein-energy wasting into a measurable, targetable and ultimately preventable problem.

Subject of Research: Development and psychometric validation of a malnutrition knowledge, attitude and practice scale for chronic kidney disease patients in China

Article Title: Development and Validation of CKD‐MKAP: A Malnutrition Perceived Knowledge, Attitude, and Practice (KAP) Scale for Patients With Chronic Kidney Diseases (CKD) in China

Article References: Zhu, S., Yusoff, H., Cheng, K. Y., Yusoff, D. M., Feng, X., Zheng, W.-K., & Chen, H. (2026). Development and Validation of CKD ‐ MKAP : A Malnutrition Perceived Knowledge, Attitude, and Practice ( KAP ) Scale for Patients With Chronic Kidney Diseases ( CKD ) in China. Nursing Open, 13(10), Article e70925. https://doi.org/10.1002/nop2.70925

Image Credits: AI Generated

DOI: 10.1002/nop2.70925

Keywords: chronic kidney disease, malnutrition, KAP scale, psychometric validation, nursing, protein-energy wasting, Delphi method, factor analysis, China, nutritional assessment, scale development, patient education