UC Irvine

Background

Maintenance hemodialysis (MHD) patients with polycystic kidney disease (PKD) have better survival than non-PKD patients. Mineral and bone disorders (MBD) are associated with accelerated atherosclerosis and cardiovascular death in MHD patients. It is unknown whether the different MBD mortality association between MHD populations with and without PKD can explain the survival differential.

Methods

Survival models were examined to assess the association between different laboratory markers of MBD [such as serum phosphorous, parathyroid hormone (PTH), calcium and alkaline phosphatase] and mortality in a 6-year cohort of 60,089 non-PKD and 1501 PKD MHD patients.

Results

PKD and non-PKD patients were 57±13 and 62±15 years old and included 46 and 45% women and 14 and 32% Blacks, respectively. Whereas PKD individuals with PTH 150 to <300 pg/mL (reference) had the lowest risk for mortality, the death risk was higher in patients with PTH<150 [hazard ratio (HR): 2.16 (95% confidence interval 1.53-3.06)], 300 to <600 [HR: 1.30 (0.97-1.74)] and ≥600 pg/mL [HR: 1.46 (1.02-2.08)], respectively. Similar patterns were found in non-PKD patients. Fully adjusted death HRs of time-averaged serum phosphorous increments<3.5, 5.5 to <7.5 and ≥7.5 mg/dL (reference: 3.5 to <5.5 mg/dL) for PKD patients were 2.82 (1.50-5.29), 1.40 (1.12-1.75) and 2.25 (1.57-3.22). The associations of alkaline phosphatase and calcium with mortality were similar in PKD and non-PKD patients.

Conclusion

Bone-mineral disorder markers exhibit similar mortality trends between PKD and non-PKD MHD patients, although some differences are observed in particular in low PTH and phosphorus ranges.