Definitions and Causes: Part I

Introduction

Wasting in the HAART Era

Guidelines

Post-Test

Introduction

AIDS Wasting Syndrome (AWS) was added as an AIDS-defining diagnosis by the Centers for Disease Control and Prevention in 1983.  AWS criteria included a 10% weight loss from baseline accompanied by diarrhea or fever for more than 30 days without another known cause.  Prior to the era of highly active antiretroviral therapy (HAART) regimens, it was estimated that between 80-90% of HIV-infected patients would experience HIV-related wasting. 

 

 While AWS defines approximately 20% of AIDS cases both pre- and post-HAART era, use of this definition alone may vastly underestimate the numbers of HIV-infected patients who experience wasting.  There are several limitations to the clinical use of the CDC AWS definition.  The CDC definition:
  • did not have a basis in HIV disease-related evidence,
  • did not consider such factors as time-dependent risk in weight losses,
  • did not consider detrimental body composition changes that may compromise health without significant changes in weight, and
  • did not acknowledge that wasting often occurs in conjunction with other AIDS-defining illnesses leading to underreporting of wasting incidence.   

 

In the clinical world where a problem needs to be recognized regardless of its ability to diagnose “AIDS,” these are huge limitations.  And yet, many clinicians hold the perception that wasting is not a big issue because the number of cases of AIDS has dropped dramatically.  In the interest of evidence-based practice, let’s look at some evidence!

 

 

 

Wasting in the HAART Era

The Nutrition for Healthy Living (NFHL) cohort study in Boston, Massachusetts has been following more than 600 HIV-infected individuals at six-month intervals since 1995.  Christine Wanke, MD has reported on the results during the last two years and has demonstrated the incidence, prevalence, and characteristics of wasting that exists today in the HAART era.  The wasting definition for this study included:

  • more than 10% unintentional weight loss since entering the study
  • initial occurrence of BMI <20
  • loss of more than 5% body weight that was sustained for at least one year

 

Dr. Wanke noted that:

·        Weight loss and wasting continue to be common experiences with a 30% incidence and 38% cumulative prevalence described in this cohort

·        Weight loss and wasting occurred in patients who:

o       Were HAART-naïve

o       Were adhering to a successful HAART regimen

o       Failed HAART

·        Simple reduced intake of nutrients did not fully explain weight losses

·        Weight loss was associated with opportunistic events, but again, this was not sufficient to fully explain weight losses

 

Dr. Wanke’s group suggested that the worst type of wasting, loss of lean tissues, continues to occur in a significant number of patients despite best efforts with HAART.  You want details?  Here they are:

·        NFHL data was evaluated and showed that between 6 month intervals of visits 50% of patients lost 5% FFM, 32% lost 7.5% FFM, and 18% lost 10% FFM

·        1803 6-month intervals suggested that 18% of the visit intervals showed loss of FFM, 11% showed 7.5% loss of FFM, and 6% showed loss of 10% FFM

·        in single incidences of 7.5% loss of FFM, 22% were female and 78% were male; in single incidences of 10% loss of FFM 18% were female and 82% were male; no differences were seen for age, CD4, viral load.

·        preliminary data analysis doesn’t suggest a linear relationship between viral load and weight or FFM loss

·        weight may not be fully restored to baseline or premorbid weight in most patients who lost weight prior to HAART use

 

In another study of 244 patients, Gerner et al notes that while there may be a normal distribution of body mass index (BMI) in HIV-infected men, there appears to be a split in the distribution of BMI in HIV-infected women with most grouped at the low and high end.  BMI didn’t appear to adequately predict the alterations in lean tissues as one would expect (and as was typical in the pre-HAART era).  Despite a more normal distribution of BMI in men, the diminished level of lean tissues, especially body cell mass, appears to be similar to the pre-HAART era when AWS was considered prevalent.  These authors note that between 60-75% of patients on HAART experienced a level of 10% or more weight loss. 

 

For many clinicians the question remains: Why is wasting important?  Alice Tang, PhD reported data evaluation from the NFHL study to respond.  In a review of data the strongest predictor of mortality was a time-dependent weight loss of  >10%.  For patients who were not on HAART regimens a BMI of <20 was a strong predictor of death, while fat-free mass was a better predictor in patients who had used HAART.  Thus, body composition evaluation may be even more important to monitor in HAART-using patients.

 

 

Guidelines, Please!

In a recent review of information, Bruce Polsky, MD, Donald Kotler, MD, and Corklin Steinhart, MD, PhD developed a set of guidelines for the assessment, diagnosis, and treatment of HIV-associated wasting.  While the spotlight is currently trained on altered body shapes and metabolic alterations, they noted that wasting of lean tissues continues to be a problem.  In their review, the authors note that:

·        Wasting continues to exist,

·        There is a difference between wasting as an ongoing process and being wasted,

·        A new definition of wasting should include a time element and account for changes in body composition that may not show up as weight loss, and

·        Wasting status should be a part of routine monitoring.

Because the diagnosis of wasting is dependent on the definition, these physicians recommended an alternate look at the criteria that is associated with health risk.  These criteria include:

·        10% loss of weight over a 12-month period of time, and/or

·        7.5% loss of weight over a 6-month period of time, and/or

·        5% loss of body cell mass (by BIA evaluation*) over a 6-month period of time, and/or

·        Body mass index <20, and/or

·        Body cell mass less than 35% of weight if BMI is <27 in males; less than 23% if BMI is <27 in females.

(* for more information on bioelectrical impedance analysis, please check out the BIA course on this site.)

 

 

 

Conclusion

In a recent presentation, Donald Kotler, MD noted, “HIV disease is very much the same [as before].  Well, at least the spelling is…” Wasting continues to exist and is often hidden less by evidence than by clinician perception that wasting is a thing of the past.  And, while we know progress is being made in the battle against HIV infection and disease, it is likely that we are only in the “eye of the storm” with nutrition-related problems as our reminder to pay careful attention.

 

Summary

AIDS wasting syndrome (AWS) continues to exist in people living with chronic HIV infection and should be identified for treatment. Because the CDC’s definition of AWS has limitations, a new and more clinically useful definition for wasting in HIV infection has been suggested and includes both time-dependent weight changes and alterations in body composition that may occur regardless of weight changes.

 

 

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Coming Soon--Parts II and III of the Wasting Course!

 

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