Hip fracture incidence and mortality in chronic kidney disease

Abstract

Background:
Individuals on renal replacement therapy (RRT) have increased fracture risk, but risk in less advanced chronic kidney disease (CKD) is unclear.

Objective:
To investigate CKD associations with hip fracture incidence and mortality.

Design:
Record linkage cohort study (GLOMMS-II).Setting Single health region in Scotland.

Participants:
All individuals (>5 years) with sustained CKD stage 3-5 and those on RRT, and a 20% random sample of those with normal renal function, in the resident population in 2003.

Outcome measures:
Outcomes were (i) incident hip fracture measured with (a) admissions or (b) deaths, with at least 5.5 years follow-up; and (ii) post-hip fracture mortality. Unadjusted and adjusted, incident (IRR) and mortality (MRR) rate ratios, were calculated using Poisson regression.

Results:
Of 39 630 individuals identified in 2003 (41% males, mean age 63.3 years), 19 537 had CKD stage 3-5, 345 were on RRT, and 19 748 had normal eGFR. Hip fracture incidence, measured by admissions, was increased in CKD stage 3-5 (compared to normal eGFR), both overall (adjusted IRR 1.49 [95% CI, 1.24-1.79]) and for individual CKD stages 3a, 3b and 4. Hip fracture incidence, measured using deaths, was increased in those with CKD stage 3b and 4. Post-hip fracture mortality, was only increased in CKD stage 4. There was only a small number of individuals and events for CKD stage 5, resulting in insufficient statistical power.

Conclusion:
Hip fracture incidence was higher in CKD stage 3-5 compared to normal eGFR. Post-hip fracture mortality was only increased in CKD Stage 4. Reducing hip fracture incidence in CKD through regular fall and fracture risk review, should reduce overall deaths after hip fracture in the population.