For patients with chronic kidney disease (CKD), the risk of elevated levels of parathyroid hormone (PTH), or hyperparathyroidism a significant complication that increases the risk of cardiovascular problems and death increases along with body weight, reports a study in the September Clinical Journal of the American Society of Nephrology.
"We knew that in people with normal kidney function obesity leads to impairment in vitamin D metabolism and elevated PTH levels, but this phenomenon was never studied in patients with CKD," comments lead author Dr Csaba P. Kovesdy, of Salem VA Medical Center, in Salem, Va. "Since both obesity and hyperparathyroidism are very complex problems in CKD, establishing an association between the two is important because of potential prognostic and therapeutic implications."
The study was based on a database of 496 U.S. veterans with moderate to severe CKD who were not yet on dialysis. The database allowed the researchers to test the association between body weight and PTH levels, while accounting for a number of possible confounding factors.
The results showed a significant association between obesity and hyperparathyroidism as body mass index increased, so did PTH levels. The relationship between increased PTH and body weight was unaffected by age, race, diabetes, or other factors.
A further analysis was done to determine if the association was present in all patients with CKD or just certain subgroups. "Interestingly, we found that obesity was only associated with higher PTH levels in patients who also showed signs of malnutrition and inflammation," says Dr. Kovesdy. "This finding may be unique to patients with CKD. Besides providing a possible explanation for why PTH levels are higher in obese patients, it may also be important for prognostic reasons, since malnutrition and inflammation are among the major complications responsible for poor outcomes in CKD."