Biochemical response to treatment of bone hyperresorption in chronically critically ill patients.

STUDY OBJECTIVE The chronically critically ill (CCI) are a subgroup of critically ill patients who have survived an acute critical illness but remain profoundly debilitated and ventilator dependent. We have previously shown that CCI patients have a very high prevalence of bone hyperresorption. The objective of this present study was to determine the biochemical response of bone hyperresorption in CCI patients to treatment with either calcitriol alone or calcitriol and pamidronate. DESIGN Retrospective survey. SETTING Respiratory care step-down unit (RCU) at a tertiary-care teaching hospital. PATIENTS Fifty-five ventilator-dependent CCI patients transferred from ICUs within the same institution who had elevated urine N-telopeptide (NTx) levels at RCU admission, who were treated with either calcitriol alone (n = 44) or calcitriol and pamidronate (n = 11), and who had urine NTx levels remeasured following treatment. INTERVENTION None. MEASUREMENTS AND RESULTS Patients treated with calcitriol alone had a significant reduction in serum parathyroid hormone (PTH; 93+/-145 pg/mL vs 40+/-28 pg/mL; p = 0.02) but not in urinary NTx (187+/-146 nmol bone collagen equivalents [BCE]/mmol creatinine [Cr] vs. 178+/-123 nmol BCE/mmol Cr, p = 0.59). In contrast, patients treated with both calcitriol and pamidronate had a significant decrease in urine NTx at follow-up (329+/-238 to 100+/-85 nmol BCE/mmol Cr; p<0.01) but not in serum PTH (36+/-29 to 53+/-51 pg/mL; p = 0.44). CONCLUSION The bone hyperresorption of CCI patients is PTH independent and biochemically responds to treatment with calcitriol and pamidronate but not calcitriol alone.