Correlation of Malnutrition Prevalence to Polymorbidity
Polymorbid medical inpatients have a malnutrition prevalence of 40-50% in tertiary care centers, representing a direct and powerful correlation where the presence of multiple chronic conditions dramatically increases malnutrition risk and severity. 1
Prevalence Data in Polymorbid Populations
The correlation between polymorbidity and malnutrition is striking and clinically significant:
Hospitalized polymorbid patients demonstrate malnutrition rates of 40-50%, which is substantially higher than the general population and represents one of the most prevalent geriatric syndromes in this population 1, 2
The prevalence increases with functional decline: malnutrition rates are below 10% in independently living older persons but escalate to two-thirds of older patients in acute care and rehabilitation hospitals 3
Malnutrition worsens during hospitalization if untreated, with nutritional risk increasing from 40.61% to 48.93% within just two weeks of admission (p = 0.036) 1
Mechanisms Linking Polymorbidity to Malnutrition
The correlation operates through multiple interconnected pathways:
Polypharmacy is significantly associated with both malnutrition and sarcopenia, creating drug-drug and drug-nutrient interactions that compromise nutritional status 3
Reduced dietary intake combined with catabolic effects of multiple diseases rapidly leads to malnutrition, particularly during acute illness exacerbations 3
Anorexia of aging is amplified by polymorbidity, with acute and chronic illness making nutritional problems widespread in this population 3
Clinical Impact of This Correlation
The malnutrition-polymorbidity correlation translates directly into adverse outcomes:
Malnourished polymorbid patients have 2.38 times higher odds of hospital length of stay ≥3 days (95% CI, 1.45 to 3.88; p < 0.001) 1
They have 2.28 times higher odds of 30-day readmission (95% CI, 1.26 to 4.12; p < 0.006) 1
Mortality rates are significantly elevated: malnutrition is associated with increased short-term and long-term mortality, with one study showing 30.5% mortality at 5 months in malnourished patients versus 9.8% in non-malnourished patients (p < 0.01) 4
Functional decline is accelerated, with malnourished patients requiring greater need for home care or intermediate care at discharge (41.8% vs 22.9%, p < 0.01) 4
Disease-Specific Patterns
Certain conditions within polymorbidity profiles show particularly strong correlations:
Infection and cancer diagnoses are associated with inadequate energy intake in patients aged 65 years or older 3
Kidney disease predicts response to nutritional treatment, with lower eGFR showing stronger clinical benefit from intervention 3
Chronic heart failure patients demonstrate strong benefit from nutritional support, suggesting disease-specific vulnerability to malnutrition 3
Critical Clinical Implications
Universal screening for malnutrition risk at hospital admission using validated tools (NRS-2002 or MNA-SF) is mandatory for all polymorbid patients, as early identification and intervention directly reduces mortality, complications, and hospital readmissions 5, 1
Common Pitfalls to Avoid:
Never delay screening or intervention: malnourished polymorbid patients have dramatically worse outcomes that begin immediately upon admission 1
Do not rely on BMI or serum albumin alone: these are insufficient indicators affected by multiple factors including chronic diseases, medications, and physical condition 6
Avoid restrictive diets that limit intake: in polymorbid patients, prevention and treatment of malnutrition takes priority over disease-specific dietary restrictions 5