High rates of death and hospitalization follow bone fracture among hemodialysis patients

Abstract

Altered bone structure and function contribute to the high rates of fractures in dialysis patients compared to the general population. Fracture events may increase the risk of subsequent adverse clinical outcomes. Here we assessed the incidence of post-fracture morbidity and mortality in an international cohort of 34,579 in-center hemodialysis patients in the Dialysis Outcomes and Practice Patterns Study (DOPPS). We estimated country-specific rates of fractures requiring a hospital admission and associated length of stay in the hospital. Incidence rates of death and of a composite event of death/rehospitalization were estimated for 1 year after fracture. Overall, 3% of participants experienced a fracture. Fracture incidence varied across countries, from 12 events/1000 patient-years (PY) in Japan to 45/1000 PY in Belgium. In all countries, fracture rates were higher in the hemodialysis group compared to those reported for the general population. Median length of stay ranged from 7 to 37 days in the United States and Japan, respectively. In most countries, postfracture mortality rates exceeded 500/1000 PY and death/rehospitalization rates exceeded 1500/1000 PY. Fracture patients had higher unadjusted rates of death (3.7-fold) and death/rehospitalization (4.0-fold) compared to the overall DOPPS population. Mortality and hospitalization rates were highest in the first month after the fracture and declined thereafter. Thus, the high frequency of fractures and increased adverse outcomes following a fracture pose a significant health burden for dialysis patients. Fracture prevention strategies should be identified and applied broadly in nephrology practices.

Figure 1. Incidence of fractures resulting in a hospital admission among DOPPS participants, by country

Only the first fracture event for each patient was included in the calculation of these rates. A/NZ = Australia and New Zealand

Figure 2. Hip fracture rates among DOPPS participants and in the general non-dialysis population, within each DOPPS country

Rates among DOPPS participants refer to hip fractures requiring a hospital admission; rates in the general population were derived from a review by Kanis et al and may include hip fractures that did not require hospitalization

Figure 3. Length of stay in the hospital for fracture-related admissions, by country

*The numbers of fracture-related hospitalizations with a reported length of stay > 120 days were: Canada - 6 any bone fractures, 4 hip fractures; France - 4 any, 3 hip; Japan - 8 any, 3 hip; Spain - 1 any, 1 hip; UK - 2 any, 2 hip.

Figure 4. Death and hospitalization rates in the year following a fracture event requiring hospitalization, by country

Rates are restricted to events happening within 1-year of the fracture (fracture admission for death, fracture discharge for hospitalization/death). The background rate is the rate among all DOPPS participants, including patients who experienced a fracture and those who did not.

Figure 5A & 5B. Time to death and hospitalization among DOPPS participants who experienced and those who did not experience a fracture requiring hospitalization, by DOPPS region

Panel A: Unadjusted survival (time to death) by DOPPS region. Panel B: Unadjusted survival without any hospitalizations (time to first hospitalization or death) by DOPPS region.

Figure 6. Mortality rates for fracture vs. background patients, by strata of patient characteristics

“Cardiovasc dis” = cardiovascular disease defined as having any of the following conditions: coronary artery disease, congestive heart failure, cerebrovascular disease, peripheral vascular disease, or other cardiovascular disease “Adj” = adjusted models; account for country, age, race (Black v. non-Black), sex, and years on dialysis Due to the large sample size of many of the strata, confidence intervals for the overall death rates are very small and therefore not visible in the figure.