Among my RDNs posed this question Lately related to BMI levels for older adults:
I’ve been seeing transfer notes from the hospital and other nursing homes with diet/nutrition histories where RDNs are charting that BMIs of less than 23 is underweight. For example, one note documented a BMI of 21.3 was underweight”for age” for a guy who was 92. State surveyors are also asking for a list of people who have BMI under 21 and wanting to find interventions on them. The MDS does not trigger for a low BMI until under 19. Do we need to adapt our practices?
Classification – Normal
BMI (kg/m2) – 18.4-24.9
Classification – Overweight
Obesity Class – None
Classification – Obesity
Obesity Class – I
BMI (kg/m2) – 30.0-34.9
Classification – Obesity
BMI (kg/m2) – 35.0-39.9
Classification – Extreme Obesity
BMI (kg/m2) – > 40
BMI is translated according to age, health history, usual body weight, and weight history.
Adults should be evaluated for signs of nutritional status and decrease using body mass index (BMI) as one of many things. Data suggests that a higher BMI range may be protective in older adults and that the standards for ideal weight (BMI of 18.5 to 25) may be overly restrictive in the elderly. A lower BMI may be considered detrimental to older adults because of association with decreasing nutrition status, possible pressure ulcers, infection and other complications. A BMI of 19 or less may indicate nutritional deficiencies, while a BMI of 30 or above indicates obesity.
In the literature, there’s a lot of conversation about a BMI of 21-23 (instead of 18/19) as considered on the low side for older adults. At exactly the exact same time, there is a lot of conversation about the”obesity paradox” saying a higher BMI might be protective against some diseases and death. There’s still lots of controversy concerning the effectiveness of BMI for older adults, regardless of what is considered”too low” or”too high”.
To our knowledge, there are no firm recommendations from any source on BMI cutoffs for older adults. The MDS activates a CAA if BMI is < 18.5, although as mentioned above a greater BMI are likely to be considered too low for older adults.
In clinical practice, the BMI number is not as important as how it pertains to an individual’s history. Monitoring changes over time is what is important.
If state surveyors question whether everybody with a low BMI needs an intervention, consider explaining that if a low BMI was normal for this individual’s life history, then we would not attempt to fix it – although interventions might be put in place for different reasons (poor intake, weight loss, wounds, etc.). And for an older person with a high BMI of 35 who was overweight their entire life, it is highly possible that lifestyle and habits are put and weight loss would likely not be necessary or successful in older age.