Abstract: TH-PO455

The Association of Body Mass Index (BMI) with Mortality and Institution of Renal Replacement Therapy (RRT) in CKD Patients in the CKD-QLD Registry: Queensland, Australia

Session Information

Category: Chronic Kidney Disease (Non-Dialysis)

  • 303 CKD: Epidemiology, Outcomes - Cardiovascular

Authors

  • Chan, Samuel Shun kwan, Kidney Health Service, Royal Brisbane and Women''s Hospital, Metro North Hospital and Health Service, Herston, Queensland, New South Wales, Australia
  • Cameron (Salisbury), Anne, CKD.QLD and the NHMRC CKD.CRE, The University of Queensland, Brisbane, Queensland, Australia
  • Wang, Zaimin, CKD.QLD and the NHMRC CKD.CRE, The University of Queensland, Brisbane, Queensland, Australia
  • Healy, Helen G., Kidney Health Service, Royal Brisbane and Women''s Hospital, Metro North Hospital and Health Service, Herston, Queensland, New South Wales, Australia
  • Hoy, Wendy E., CKD.QLD and the NHMRC CKD.CRE, The University of Queensland, Brisbane, Queensland, Australia
Background

Dialysis patients who are overweight and obese are reported to have better survival compared with those with lower BMI. We do not know if this is so in CKD patients.

Methods

A retrospective analysis of preterminal CKD patients from two major sites enrolled in the CKD.QLD registry was undertaken between May 2011 and July 2015. Associations of WHO BMI categories with subsequent death without RRT and with RRT were examined using Cox regression modelling, adjusting for hospital site, demographic variables, CKD stage, primary renal disease and co-morbidities.

Results

Of the 2,059 patients (median age 68, IQR 56–77 yr), median (IQR) BMI was 29.7 (25.9-35.0)kg/m2. 216 died without RRT (10%) and 151 started RRT (7%). Median (IQR) ages at death and start of RRT were 78 (IQR 71-84) and 61 (IQR 49-69) yr, respectively. The incidence rates for death and start of RRT was 41.8 and 34.4 per 1000 person-years, respectively. With normal BMI (<25) persons as the referent group, the adjusted hazard ratios (HR) (95% CI) for death were 0.57 (0.40-0.81) p=0.002, for overweight subjects, 0.59 (0.41-0.85) p=0.004, for obese subjects, and 0.94 (0.56-1.60) p=0.83, for morbidly obese subjects. The adjusted HR for RRT were 1.08 (0.69-1.70) p=0.73, for overweight subjects, 1.09 (0.69-1.73) p=0.71, for obese subjects, and 1.04 (0.56-1.92) p=0.90, for morbidly obese subjects.

Conclusion

Demographic and clinical characteristics of CKD patients who die without RRT are different to patients who commence RRT. Overweight and obese, but not morbidly obese, subjects appear to be protective against death, compatible with the phenomenon observed in dialysis patients. In some patients, lower BMI may mark ill health and advanced age. However, with adjustments, there is no significant association of BMI with the likelihood of starting RRT.

Funding

  • Government Support - Non-U.S.