Incluido en la revista Ocronos. Vol. III. Nº 7– Noviembre 2020. Pág. Inicial: Vol. III;nº7:28
Autor principal (primer firmante): María Salinas
Fecha recepción: 23 de octubre, 2020
Fecha aceptación: 13 de noviembre, 2020
Ref.: Ocronos. 2020;3(7):28
María Salinas 1,2
Maite López-Garrigós 1,3
Emilio Flores 1,4
Pablo Leiva-Salinas 4
Ana Santo-Quiles 1
Carlos Leiva-Salinas 5
1 Clinical Laboratory, Hospital Universitario de San Juan, San Juan de Alicante, Spain
2 Department of Biochemistry and Molecular Pathology, Universidad Miguel Hernández, Elche, Spain
3 CIBER en Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
4 Department of Clinical Medicine, Universidad Miguel Hernandez, Elche, Spain
5 Department of Radiology, University of Missouri, Columbia, MO, USA
Introduction: Malnutrition needs early detection for its correction and appropriate monitoring. Evaluation of patients at risk of malnutrition through Controlling Nutritional (CONUT) Score, calculated through total lymphocytes, serum albumin and total cholesterol, has been studied in hospitalized patients, but not in primary care. Our aim was to automatically calculate CONUT in the last decades of life in primary care patients, when involved laboratory markers were requested, to identify patients at risk of malnutrition, living at home and institutionalized; also the potential expenses to calculate CONUT in measuring serum markers when no requested.
Material and Methods: We calculated CONUT in primary care patients over 60 when laboratory markers were requested, compared when living independently or in nursing homes and counted the number of albumin and/or total cholesterol tests needed to calculate CONUT in requests with total lymphocytes and serum availability, and hypothetical economic cost.
Results: Out of the 44.029 requests from primary care patients over 60, CONUT was calculated in 5858. 1870 (31.9%) showed risk of malnutrition and the number of patients increased over decades. Those living independently, had lower rates of risk of malnutrition (P<.05). In one year, through an expense of 1829 € in measuring the serum non requested tests, we could have screened for risk of malnutrition the subjects over 60 that underwent laboratory testing. 506€ if only focusing on over 80.
Conclusion: CONUT score increased over the last decades of life and could be calculated in all primary care patients over 60 at a very affordable cost.
Risk of Malnutrition; Older people; Nutritional assessment; CONUT; Strategy
Malnutrition needs early detection for its correction and appropriate monitoring (1).
Nutritional status evaluated through Controlling Nutritional (CONUT) Score, a calculation that involves total peripheral lymphocytes, serum albumin, and total cholesterol, has been shown as a valuable tool for the early detection and monitoring of clinical under nutrition.
Nutrition status is important at every stage of life to maintain good health, but it is especially crucial in the elderly as it is independently associated with acute care hospitalization and mortality (2). Since the CONUT introduction in 2002 (3), its main application has been to evaluate and quantify the prevalence of malnutrition at hospital admission (4). In fact evaluation of nutritional status through CONUT score may provide additional prognostic information in elderly hypertensive patients, as higher scores exhibited higher mortality within 90 days after admission (5). Moreover, research studying the short-term prognostic assessment in hospitalized elderly also found that CONUT was a good predictor of short- and medium-term mortality (6). However CONUT score has not been tested in primary care elderly patients.
Elderly population is increasing dramatically, and the group over 85 years old -the “oldest old” – is the most rapidly growing segment (7), because of increases in life expectancy and reduced mortality at older ages. Malnutrition is more common and is increasing in the elderly, making nutrition a very important element in this population because it affects the aging process. Pathological changes with aging as medical, drugs, or psychological and social, promote the anorexia of aging. Chronic illness, depression, medication and social isolation occurring in this population, and also physical and cognitive impairment also can play a role in nutritional inadequacy. In this context malnutrition screening is vital, not just in identifying patients at risk of malnutrition but also in its monitoring (8).
Our aim was to automatically calculate the CONUT score in a large number of primary care patients older than 60, living independently and in nursing homes, and evaluate the costs of a potential intervention involving CONUT as a screening tool in old population undergoing laboratory testing.
We hypothesized that CONUT score could be a valid first line tool to screen for risk of malnutrition in the last decades of life in primary care patients living independently and in nursing homes.
Material and methods
Setting and subjects
The clinical laboratory is located in a 370-bed suburban University Community Hospital that serves the population of the Health Department (HD) (234551 inhabitants). It receives samples from primary care patients that are phlebotomized in nine different primary care centres as well as in nursing homes, samples that are transported by couriers to the laboratory. Requests are made by general practitioners (GPs) via computerized order entry, and results are also automatically sent to the electronic medical record. In this study, we included all community inhabitants over 60 years old within the HD covered by the clinical laboratory. The study was approved by the Hospital Research Committee, which waived the need for patient consent.
A cross sectional study was designed from January 1st 2018 to December 31st 2018. In consensus with GPs, the CONUT score was automatically calculated by our Laboratory Information System (LIS) for every primary care patient over 60 when the three involved laboratory markers were requested, in accordance with the tool showed in Table 1.
The blood samples were collected using BD vacutainer tubes (Beckton Dickinson, NJ, USA).
Albumin was measured through an immunoturbidimetric assay and total cholesterol through an enzymatic colorimetric method (Cobas 8000, Roche, Mannheim, Germany).
Total lymphocyte were counted with clinical hematology analyzers (Sysmex, Kobe, Japan).
For all primary care requests of patients over 60, we collected demographic data and CONUT value from the LIS (iGestlab®). We classified results by patient’s age, and compared them for the different age brackets. For the potential strategy involving CONUT as a screening tool in all laboratory requests from primary care patients over 60, we counted the number of albumin and/or total cholesterol to be measured in requests with measured total number of lymphocytes and also serum availability. We calculated the hypothetical economic cost based on both tests prices (0.09€ for total cholesterol, and 0.08€ for albumin).
Demographic summary statistics are reported as median (IQR) for continuous and frequency (%) for categorical variables. Together with the requests’ basic information, differences were assessed using Chi-square, U-Mann Whitney test and Kruskal-Wallis test where applicable. A two-sided p ≤ 0.05 rule was utilized as the criterion for rejecting the null hypothesis of no difference. Statistical analyses were done using Statistical Package for the Social Sciences (SPSS), Version 22 (IBM Corp., Chicago, Illinois, USA).
During the study period, the clinical laboratory received 44.029 requests from primary care patients over 60, with a median (IQR) age of 73 (66-81), and 26.193 (59,5%) were women. CONUT score was calculated in 5858, as the 3 markers involved were requested. Thirty two % were men, with a median (IQR) age of 78 (70-86). One thousand eight hundred seventy (31.9%) showed risk of malnutrition according to the CONUT score (Table 2), corresponding 1549 (82.8%) patients to low, 288 (15.4%) mild and 33 (1.8%%) to severe scores. Those living independently were more likely female (P<.05), and younger (P<.05), and had lower rates of risk of malnutrition (P<.05) (Table 2).
In each decade from 60 years of age, the percentage of patients at risk of malnutrition increased (Figure 1) and was lower in patients living at home. The percentage of patients with mild, moderate and severe CONUT score was also higher when living in nursing homes (Figure 2).
Through an expense of 1829€, the laboratory could have screened the subjects older than 60 that underwent a laboratory test. That expense would have been 506€ if only focusing on older than 80.
The intervention to automatically calculate the CONUT score in primary care patients over 60, when the three involved markers were requested, was successful and at no extra cost. The number of patients at risk of malnutrition through the CONUT score increased with patient age, and was higher for subjects living in nursing homes. By measuring non-requested albumin and/or cholesterol tests needed for CONUT calculation, when lymphocyte had been counted and serum availability, it would be possible to assess the risk of malnutrition of all primary care patients over 60 undergoing laboratory testing, at a very affordable cost, especially when over 80.
32% of the evaluated primary care patients over 60, presented risk of malnutrition evaluated through the CONUT score. Although the risk of malnutrition is higher in old population (2), this figure could seem too high. The reason is that the score was only calculated in 12% of the primary care patients over 60, patients that could present a clinical suspicion of risk of malnutrition as serum albumin was ordered. In fact serum albumin was only requested and measured in about 12% of primary care patients over 60 that underwent laboratory testing.
CONUT score was significantly higher in subjects living in nursing homes, similar results that the observed when using other nutritional tools in hospitalized patients, and compared with outpatients (6). These results could be explained because the studied nursing home residents are older, and usually suffer more often from comorbidity and multimorbidity.
There is a need to adapt our health care resources to the demographic changes. In fact, population aging is putting some pressure on the health systems that must adapt and find the appropriate cost-effective technologies to identify and prevent the associated chronic conditions, including the assessment and management of malnutrition (8), being crucial to identify the patients at risk of malnutrition and take measures as early as possible(9). However, malnutrition is often not recognized in daily practice, and consequently patients could be untreated, despite the recommendation of the routine use of a simple screening procedure (10).
According to our study results, CONUT could become the tool of choice to detect the risk of malnutrition in the last decades of life in patients attended in primary care, for subsequently confirmation through proven nutritional assessment tools.
However, the study had some limitations. First, CONUT has not been studied, and compared with the traditional nutritional tools, in order to validate the results. Second, the calculated economic investments may not apply to other countries or settings, since our laboratory belongs to the Public Health Network, where reagent prices tend to be low.
The CONUT score can be used as a laboratory front-line laboratory marker to identify elderly primary care patients at risk of malnutrition, to later be confirmed or discarded using traditional nutritional tools. CONUT increased with patient age, and was higher for subjects living in nursing homes. CONUT can be calculated at no additional cost in every elderly primary care patient that undergoes laboratory testing when the three involved laboratory markers are requested and at a very low cost by measuring the non-requested test.
The authors would like to express their deep gratitude to all the clinical laboratory staff.
The study was approved by the Hospital Research Committee, which waived the need for patient consent.
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