To assess the influence of malabsorption on nutritional status and energy expenditure in patients at different stages of HIV infection.

• Patients with known non-AIDS-related malabsorption disease
• With malignant or Kaposi's sarcoma
• Treatment with drugs that could modify REE such as corticoids.

Recruitment

HIV-seropositive patients were recruited consecutively from the HIV outpatient department.

Design

Case-control study. 

Blinding Used

Implied for measures.

Statistical Analysis

• Differences between groups were analyzed using the Mann-Whitney non-parametric test
• Paired data were analyzed by the Wilcoxon non-parametric test
• Simple correlations were determined using Spearman's correlation coefficient
• As REE was significantly related with TBIA-FFM (R=0.80, P<0.001), the unexplained residual of the REE in each individual was calculated by the general linear model procedure using the FFM as covariant. The adjusted REE (REE_a) for each individual was calculated by adding the individual residual REE to the mean REE of the whole group.

Timing of Measurements

• From November 1995 to December 1996
• Patients were hospitalized for three days for the conduct of the analyses.

Dependent Variables

• Weight
  • Weight and height determined on admission
  • Weight change in previous one and three months was recorded
  • IBW was established by use of Spanish population reference data
  • Actual body weight expressed as a percentage of IBW
  • BMI was calculated.
• Body composition: Tetrapolar bioelectrical impedance
• Energy expenditure
  • Open-circuit indirect calorimetry
  • 24-hour urinary nitrogen excretion was measured using the Kjeldahl technique
  • REE_m was calculated from VO₂, VCO₂ and urinary nitrogen excretion using the equation of Weir
  • Estimated resting energy expenditure was calculated from Harris and Benedict equations.
• Absorption studies
  • Standard D-xylose test was used to evaluate sugar absorption
  • Fat absorption was determined by the ¹⁴C triolein breath test
  • HIV-infected individuals were reclassified into two groups with respect to the presence or absence of malabsorption.

Independent Variables

•  HIV-positive patients divided into three groups
  • Asymptomatic HIV patients who had not had an AIDS-defining illness
  • AIDS patients without secondary infection
  • AIDS patients, who at the time of the study, had symptoms or signs of active secondary infection.
• AIDS patients also sub-divided into no-malasorption and malabsorption categories
• Clinically healthy volunteers served as controls.

Control Variables

 None stated; implied some of the dependent variables serve as controls.

• Initial N
• 50 (36 men and 14 women) HIV-seropositive patients
• 19 (14 men and five women) clinically healthy controls from hospital and laboratory staff with low risk for HIV infection
• For fat malabsorption test, another control group of 10 healthy subjects.
• Attrition (final N): Same as initial
• Age: HIV-positive 34.8 (range 25 to 65)
• Ethnicity: Not given (implied Spanish)
• Other relevant demographics: Not given
• Anthropometrics: See Table One in Results; disease and medication information
  • Diagnosis of AIDS was established according to CDC
  • Patients were receiving antiretroviral treatment, according to standard protocols that included combination of the two nucleoside reverse transcriptase inhibitors [zidovudine plus didanosine (DDI) or zidovudine plus zalcitabine (DDC)]
  • Twenty patients were receiving oral fluconazol for antifungal prophylaxis and oral co-trimoxazole or pentamidine aerosol for P. carinii prophylaxis.
• Location: Patients were recruited from the HIV outpatient department at the Hospital Sant Joan de Reus.

 Table One: Biometric Characteristics of the Study Population

Table Two: Summary of the Absorption Tests

* P<0.05
** P<0.001, compared with controls
^# P<0.05
^## P<0.001, compared with Group Three.

Table Three: Body Composition and Resting Energy Expenditure (REE) at Different Stages of HIV Infection

* P<0.05
** P<0.005
*** P<0.001, compared with controls
^# P<0.05, compared with Group Three.

Table Four: Nutritional Status, Body Composition and Resting Energy Expenditure (REE) with Respect to Presence or Absence of Malabsorption

*P<0.05
** P<0.005
*** P<0.001, compared with controls
^# P<0.05
^## P<0.005, compared with non-malabsorptive.

Other Findings

• In the overall patient group, a significant correlation between CD4 counts and peak output (R=0.49, P<0.001) as well as total output of (¹⁴CO₂) (R=0.36, P<0.01) was observed
• With respect to stage of HIV infection, malabsorption was found in nine patients (53%) of Group One, 11 patients (69%) of Group Two and 14 patients (82%) of Group Three
• Significant negative correlation between weight loss during the previous three months and five-hour xylose excretion (R=-0.30, P<0.05) as well as peak triolein output (R=-0.38, P<0.01) in the overall patient population
• Negative correlation between weight loss during the previous one month and peak output (R=-0.30, P<0.05) as well as total output of triolein (R=-0.29, P<0.05)
• 34 (68%) patients evidenced malabsorption; 27 (54%), with respect to sugar malabsorption and 21 (42%) to fat; 14 (28%) patients had sugar and fat malabsorption
• Significant correlation beteen sugar and absorption was observed (R=0.41, P<0.05)
• Half of individuals with malabsorption reported anorexia; five patients had diarrhea during the course of the study but stool cultures were negative
• When REE was analyzed at different stages of the disease and, with the presence or absence of malabsorption taken into account, REE_m was lower in patients with opportunistic infections and malabsorption, although the differences were not statistically significant.

• Findings demonstrate that hypermetabolism is not a constant phenomenon in HIV infection
• Factors such as malabsorption and decrease in caloric intake that are often secondary, are probably of greater importance in explaining the observed weight loss
• Malabsorption was a frequent phenomenon in HIV infection and was present in early stages of the disease, as well as in asymptomatic patients
• Malabsorption and secondary anorexia were the aspects responsible for the weight los observed in the HIV-infected patients, particularly in those with associated opportunistic infection
• The high incidence of malabsorption and its significant correlation with weight loss suggests that this parameter needs to be taken into account in clinical monitoring of AIDS patients.