The FARO Survey was performed on 2453 Italian haemodialysis (HD) patients followed prospectively from 28 dialysis centres over a 24-month period. The main results suggest that active vitamin D therapy was associated with improved survival in these patients, even when serum intact parathyoroid hormone (PTH) levels are lower than 150 pg/ml.
It has been observed that an high percentage of HD patients have low PTH levels. In fact, about 35% of those subjects have PTH < 150 pg/ml , that is considered the lower limt for the K/DOQI Guidelines. Furthermore, HD patents with lower PTH have an higher mortality risk, but the cause of this association has not been elucidated. Usually, HD patients with low PTH do not receive active vitamin D to avoid further reduction of this hormone and increase the risk of adynamic bone disease. Surprisingly, our results demonstrate, for the first time, that HD patients with serum intact PTH lower than 150 pg/ml that do not received any active vitamin D have a poorer prognosis compared with treated HD subjects.
Survival data from the FARO Study suggest that both calcitriol and paricalcitol, at low doses, given to HD patients with serum intact PTH in the range of 100-150 pg /ml (new KDIGO Guidelines), improve survival after 18-month period in comparison to HD patients that do not recevie any vitamin D.
The FARO Survey is not a RCT, but it is an observational Study. Anyway, these data suggest that therapy with low doses of active vitamin D should not be stopped in HD patients only because serum intact PTH is lower than 150 pg/ml, but it should be continued, if serum calcium and phosphate are in the "normal" range.