Associations between coronary calcification on chest radiographs and mortality in hemodialysis patients.

BACKGROUND

KDIGO (Kidney Disease: Improving Global Outcomes) guidelines recommend lateral abdominal radiographs to assess vascular calcification in incident dialysis patients. However, nearly all dialysis patients in the United States receive chest radiographs at dialysis therapy inception, which may provide readily available information on coronary artery (CAC) and aortic arch calcification (AAC). We determined the prevalence of CAC and AAC visible on plain chest radiographs and their associations with mortality in our dialysis population.

STUDY DESIGN

Retrospective analysis.

SETTING & PARTICIPANTS: 93 participants who received maintenance hemodialysis at the San Diego Veterans Affairs Medical Center in 2009-2010.

PREDICTOR

Presence of CAC and AAC as evaluated by a radiologist.

OUTCOME

All-cause mortality.

RESULTS

Average age was 64 years, 22% were African American, and 97% were men. CAC and AAC prevalences were 25% and 58%, respectively. During 20 months' follow-up, 28% died. CAC was associated with mortality in models including cardiovascular (HR, 2.41; 95% CI, 1.04-5.59) and dialysis-related (HR, 2.86; 95% CI, 1.24-6.60) risk factors. AAC was associated with HRs of 5.25 (95% CI, 1.46-17.72) in cardiovascular risk factor-adjusted models and 7.31 (95% CI, 2.03-26.34) in dialysis models. When CAC and AAC were both included in models, both CAC (HR, 3.40; 95% CI, 1.24-9.36) and AAC (HR, 6.23; 95% CI, 1.64-23.66) remained significantly associated with mortality.

LIMITATIONS

The study sample is relatively small and mostly male.

CONCLUSIONS

CAC and AAC are highly prevalent on chest radiographs in dialysis patients and strongly associated with mortality independent of one another. Because these images are nearly ubiquitous, inexpensive, and often obtained for other indications, they should be considered for risk assessment in hemodialysis patients. Future studies are required to determine whether CAC or AAC on chest radiography is additive or duplicative of the risk of aorto-iliac calcification on lateral abdominal radiographs currently suggested by KDIGO.