Associations Between Body Mass Index and Clinical Outcomes Stratified by Age in Patients Undergoing Maintenance Hemodialysis.

BACKGROUND

Our study aimed to investigate the association between body mass index and clinical outcomes by age group in a population-based cohort of patients having HD.

METHODS

The data collected by the Health Insurance Review and Assessment Service during HD quality assessment programs and the claims and death data were retrospectively analyzed (n = 71,382). The patients were divided into four groups according to their age. Each group was further divided into four groups in accordance with previous guidelines: underweight group; normal group; overweight group; and obese group.

RESULTS

The age groups were composed of the following: 41,395 patients aged < 65 years, 18,329 patients aged 65-74 years, 10,354 patients aged 75-84 years, and 1304 patients aged ≥ 85 years. In all age groups, the all-cause mortality of the underweight group was higher than that of the normal group. Multivariable Cox regression analyses revealed that the cardiovascular event outcomes of the patients aged < 65 years and those aged 65-74 years in the overweight and obese groups were better than those in the normal group. However, in patients aged ≥ 75 years, the association between body mass index and cardiovascular event outcomes was attenuated.

CONCLUSIONS

Low body mass index was associated with poor patient survival irrespective of age. Conversely, patients in overweight or obese groups had modestly lower or comparable all-cause mortality relative to those with normal body mass index. In patients aged < 65 years, patients with low body mass index showed a higher risk of cardiovascular event compared with those with normal body mass index.