Malnutrition and clinical outcomes: the case for medical nutrition therapy.

Malnutrition is defined as a state of nutritional insufficiency attributable to either inadequate dietary intake or defective assimilation or use of food ingested (1). Clinically important malnutrition is frequently diagnosed if serum albumin level is less than 3.5 g/dL,(1) total lymphocyte count is less than 1,800 [mm.sup.3], or body weight has involuntarily decreased more than 15% (1). The purpose of this article is to review available literature on malnutrition and nutrition support interventions - costs, benefits, and outcomes. Substantial evidence exists that medical nutrition therapy,(2) including nutrition assessment and appropriate nutrition interventions, saves lives and reduces morbidity and that nutrition support improves health outcomes and lowers costs.

Public policymakers, administrators of health systems, third-party payers, and patients are requiring documentation of health care quality and cost-effectiveness. As health care expenditures consume ever larger portions of budgets, pressures are mounting to eliminate services that do not have clearly demonstrable benefits. Nutrition services, along with many other services, are being scrutinized.

This article presents data that should not be overlooked when dietitians, researchers, administrators, and policymakers seek to determine the outcomes and cost-effectiveness of nutrition interventions. A search of the literature was conducted, and well-designed studies that demonstrate the outcomes of nutrition modalities are reported. Consistent evidence supports the following findings: (a) malnutrition is associated with negative health outcomes and increased use of resources; (b) nutrition support provided to malnourished patients across a range of medical conditions reduces complications, morbidity, length of hospital stay, and mortality; and (c) nutrition support of malnourished patients reduces overall use of resources.

PREVALENCE OF MALNUTRITION

Malnutrition is a critical health problem among all ages and across the continuum of care. It is estimated that more than 15 million people are treated yearly in US hospitals for illnesses, injuries, and social conditions that place them at high risk for malnutrition (3).

Malnutrition occurs in even the best of US hospitals. In eight studies involving more than 1,347 hospitalized adult patients, 40% to 55% were found to be either malnourished or at risk for malnutrition (4-11), and up to 12% were severely malnourished (12). Data on the prevalence of malnutrition in children are lacking. Malnutrition in adults occurs in all diagnosis groups (7,8), and after prolonged hospitalization, malnutrition worsens and many well-nourished patients experience a decline in nutritional status (4,5,13). Malnutrition occurs in large urban teaching hospitals and small community hospitals (14). A study of medical patients at the University of Alabama revealed that the rate of high likelihood for malnutrition, although improved since 1976, was still 38% in 1988 (13). Likelihood of malnutrition is a nutrition assessment score developed by Weinsier et al (5) that combines weighted subjective and objective parameters. The score is highly predictive of subsequent morbidity and mortality during hospitalization.

The reasons for the high prevalence of malnutrition are many (15), including some that are unavoidable, such as a consequence of some diseases. Social conditions that limit the ability to purchase, prepare, or consume food also contribute to malnutrition. Other reasons such as lack of early recognition or the absence of access to appropriate medical nutrition therapy may be modifiable (15). Often medical nutrition therapy does not receive attention as a part of medical care because it has been considered part of basic room and board costs. Lack of consistent reimbursement for nutrition assessment and therapies may also preclude identification and treatment of malnutrition or its early risk factors.

OUTCOMES AND COSTS OF MALNUTRITION

In light of today's interest in health care costs, researchers are looking at malnutrition as a hidden cause of rising costs (16). Many retrospective and prospective studies of medical and surgical patients show that compared with well-nourished patients, malnourished patients, regardless of age, endure longer hospital stays (5,17-21) and have higher costs (17,19,20,22-27). Additionally, malnourished patients experience slower healing (28-31), more complications (19,32-41), and increased mortality rates (5,13,19,21,38,42-46).

Surgical patients with likelihood of malnutrition are two to three times more likely to have minor and major complications and excess mortality (32-34). They have substantially longer lengths of stay in the hospital compared with well-nourished patients. Length of hospital stay can be extended by 90% in clearly malnourished medical and surgical patients (17-19).

The presence or likelihood of malnutrition increases the costs of hospitalization because of increased lengths of stay. Hospital charges have ranged from 35% to 75% higher in malnourished patients than in well-nourished patients, and these higher charges are directly attributable to increased length of stay and increased use of resources for treatment of complications associated with malnutrition (17,20,22,23,27).

The consistency of the associations among malnutrition and increased morbidity, extended length of hospital stay, and increased hospital costs strongly suggests that malnutrition is linked to negative health outcomes, greater use of resources, and increased costs in several patient populations. Data are lacking, however, to causally link malnutrition to increased morbidity and mortality in all patient populations. More data are needed on the interaction of nutritional risk with age, functional debilitation, and the type and severity of the underlying disease state.

METHODS OF IDENTIFYING NUTRITIONAL RISK

Health care providers can readily identify malnourished patients. Nutrition assessment can be done with readily available and relatively inexpensive methods. The methods chosen must be sensitive and specific and have positive predictive value. Clinical indicators coupled with patient histories can effectively document the presence or likelihood of malnutrition (47). The expertise of available personnel, laboratory capability, cost, and the patient population will determine the selection of initial screening and follow-up assessment tools. There is no universally accepted index of nutritional status, but several indicators have proved helpful in evaluating the presence or likelihood of malnutrition.

A laboratory test profile (including determination of total protein level, serum albumin level, and lymphocyte count) has been shown to be a specific and sensitive predictor of postoperative complications in 520 patients older than 60 years undergoing elective surgery (48). Albumin and hematocrit levels were found to predict longer hospital lengths of stay and mortality in a study …