The cardiothoracic ratio (CTR) measured by chest radiography may be a useful, non-invasive method to predict the risk of early death in hemodialysis patients with secondary hyperparathyroidism (SHPT).
After their evaluation of a subset of 2266 Japanese hemodialysis (HD) patients with SHPT from the MBD-5D study, Hiroaki Ogata, MD, of Showa University in Kanagawa, Japan, and colleagues reported that higher CTR was associated with a significantly increased risk of death from any cause, death from cardiovascular disease (CVD), and a composite outcome of all-cause mortality and CVD-related hospitalizations. The investigators tracked CTR over time, then evaluated it by quartile. Using CTR less than or equal to 46.8 as the referent, patients with a CTR of 46.8% to 50%, more than 50% to 53.6%, and more than 53.6% had a 1.4, 1.9, and 2.6 times greater risk of all-cause mortality, respectively. The risks of dying from CVD were 1.8, 3.1, and 3.5 times greater, and the risks of the composite outcome were 1.2, 1.7, and 1.8 times greater, respectively.
Previous research found an independent relationship between CTR, left ventricular mass, and target organ damage in hypertension patients. In the present study, CTR was associated with a range of clinical factors linked with cardiovascular mortality in HD patients, including age, sex, body mass index, cardiovascular comorbidities, dialysis vintage, dialysate calcium level, and intact parathyroid hormone, phosphorus, hemoglobin, and phosphate binder use.
“The CTR is an easy, reliable, and inexpensive tool for evaluating left ventricular hypertrophy and volume status without using specific equipment or technical modalities, such as ultrasonic echocardiography or magnetic resonance imaging,” Dr Ogata, MD and colleagues stated in a paper published online ahead of print in Clinical Experimental Nephrology.
Their findings suggest that efforts to reduce CTR or prevent its increase, including aggressive volume control, optimal anemia control, and CKD-MBD management, “could potentially reduce the CVD morbidity and mortality rates in HD patients.”
Among the limitations, the investigators noted that arrhythmia, particularly atrial fibrillation, and heart valvular diseases were not accounted for in the study. These conditions occur more often in HD patients and may increase CTR.
Hiroaki Ogata H, Kumasawa J, Fukuma S, et al. The cardiothoracic ratio and all-cause and cardiovascular disease mortality in patients undergoing maintenance hemodialysis: results of the MBD-5D study Clin Exp Nephrol. doi: 10.1007/s10157-017-1380-2