Cachexia in rheumatoid arthritis is not explained by decreased growth hormone secretion.
OBJECTIVE
Patients with rheumatoid arthritis (RA) lose body cell mass (BCM) by unknown mechanisms. Since the loss of BCM in normal aging individuals parallels the characteristic age-related decline in growth hormone (GH) secretion, this study was carried out to determine whether further decreased GH secretion plays a role in the pathogenesis of this loss of BCM in RA patients, termed "rheumatoid cachexia."


METHODS
GH secretory kinetics were determined by deconvolution analysis in 16 patients with RA and 17 healthy controls matched for age (mean +/- SD 45.4 +/- 13.2 years and 47.1 +/- 14.6 years, respectively), sex, race, and body mass index. Blood samples were obtained every 20 minutes for 24 hours. Body composition was ascertained using total-body potassium (TBK) as a measure of BCM and dual x-ray absorptiometry to determine fat mass.


RESULTS
BCM was reduced in patients with RA compared with healthy controls (mean +/- SD gm TBK 79.5 +/- 9.5 versus 94.9 +/- 11.9; P < 0.0005), but there was no difference in fat mass. GH kinetic parameters in patients with RA did not differ from those in controls.


CONCLUSIONS
These findings suggest that GH kinetics are unaltered in RA patients compared with healthy subjects; thus, GH deficiency does not account for rheumatoid cachexia.
Rall
Laura C
LC
Nutrition Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, 711 Washington Street, Boston, MA 02111, USA.
Walsmith
Joseph M
JM
Snydman
Laura
L
Reichlin
Seymour
S
Veldhuis
Johannes D
JD
Kehayias
Joseph J
JJ
Abad
Leslie W
LW
Lundgren
Nancy T
NT
Roubenoff
Ronenn
R
D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000150:complications*; D002100:Cachexia / Q000209:etiology*; D005260:Female; D019382:Human Growth Hormone / Q000097:blood / Q000172:deficiency* / Q000378:metabolism*; D006801:Humans; D007375:Interleukin-1 / Q000032:analysis; D015850:Interleukin-6 / Q000032:analysis; D007963:Leukocytes, Mononuclear / Q000737:chemistry; D008875:Middle Aged; D011188:Potassium / Q000032:analysis; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis
D007375:Interleukin-1; D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha; D019382:Human Growth Hormone; D011188:Potassium