Subjective Global Assessment (SGA)

The Subjective Global Assessment (SGA) is a clinical tool used to evaluate a patients nutritional status. Developed in the early 1980s by Dr. Richard D.Stringer and colleagues, SGA combines a focused medical history with a physicalexamination component. Unlike many laboratorybased scores, it relies on the clinicians judgment, making it quick, inexpensive, and applicable across a wide range of settings, from acutecare hospitals to community clinics.

Why SGA Matters

Malnutrition is an independent predictor of morbidity, mortality, prolonged hospital stay, and increased healthcare costs. Early identification allows timely intervention, which can improve outcomes, reduce complications, and lower expenses. SGA has been validated in diverse populationsmedical, surgical, oncology, and intensivecare patientsand remains one of the most widely adopted nutritionscreening instruments worldwide.

Components of the Assessment

1. Medical History (Subjective)

The history portion explores five key domains:

1. Weight Change: Unintentional loss of >5% within the last month or >10% over six months is significant.
2. Food Intake: Reduced intake due to anorexia, nausea, dysphagia, or socioeconomic factors.
3. Symptoms Affecting Intake: Persistent diarrhea, vomiting, or heartburn.
4. Functional Capacity: Decline in ability to perform usual activities, suggesting catabolic stress.
5. Metabolic Stress: Presence of infection, trauma, major surgery, or cancer that elevates energy requirements.

2. Physical Examination (Objective)

The examiner looks for visible signs of tissue loss and fluid status:

• Loss of subcutaneous fat (triceps, chest, and scapular regions).
• Muscle wasting (temporal muscles, quadriceps, deltoids).
• Presence of edema or ascites, which may mask weight loss.

Scoring and Interpretation

After gathering history and performing examination, the clinician assigns the patient to one of three categories:

• SGAA Well nourished: No significant weight loss, normal intake, no functional decline, and no obvious physical signs of malnutrition.
• SGAB Moderately or suspected malnourished: Mild to moderate weight loss, reduced intake, or some physical wasting.
• SGAC Severely malnourished: Marked weight loss, severe reduction in intake, pronounced muscle/fat loss, and often edema or fluid overload.

These categories guide clinical decisions:

Advantages of SGA

• Speed and simplicity: Completed in 510minutes by a trained clinician.
• No special equipment: Relies on bedside observation and interview.
• Strong predictive value: Consistently correlates with outcomes such as length of stay, infection rates, and survival.
• Applicability: Works in adult and pediatric populations, across inpatient, outpatient, and longtermcare settings.

Limitations and Considerations

• Subjectivity: Accuracy depends on the assessors experience; training improves interrater reliability.
• Obscured fluid shifts: Edema or ascites can hide true weight loss; careful physical exam is essential.
• Not a quantitative tool: SGA does not provide exact caloric or protein deficits; it should be complemented by detailed dietetic evaluation when needed.
• Less suitable for highly specialized populations: Certain diseasespecific tools (e.g., the Malnutrition Universal Screening Tool for elderly) may capture nuances missed by SGA.

Implementation Tips

To incorporate SGA effectively into clinical practice, consider the following steps:

1. Training: Conduct brief workshops using case studies; assess interrater agreement with kappa statistics.
2. Standardised forms: Use a printed or electronic checklist to ensure all five history items and physical signs are captured.
3. Integration with electronic health records (EHR): Embed the SGA category as a selectable field, prompting alerts for SGAB/C patients.
4. Reassessment schedule: Reevaluate at admission, after major surgery, and weekly for ICU patients.
5. Multidisciplinary followup: Link SGA results to dietitians, pharmacists, and physiotherapists for comprehensive care.

Research Highlights

Numerous studies validate SGA across settings:

• In a metaanalysis of >30,000 surgical patients, SGAC predicted a 2.5fold increase in postoperative complications compared with SGAA.¹
• Oncologic patients assessed with SGA demonstrated a stronger correlation with overall survival than serum albumin alone.²
• Criticalcare trials show that early nutrition therapy guided by SGA reduced ventilator days by an average of 1.2 days.³

Conclusion

The Subjective Global Assessment remains a cornerstone of clinical nutrition assessment because it blends simplicity with robust prognostic power. When performed by trained staff and integrated into routine workflows, SGA enables early detection of malnutrition, prompts timely intervention, and ultimately improves patient outcomes. While it should not replace detailed dietary analysis in complex cases, SGA offers an efficient firststep screening that can be universally applied across healthcare environments.