SAMUEL CHAN1,2,3, ANNE CAMERON2,3, ZAIMIN WANG2,3, SREE K VENUTHURUPALLI2,3,4, KEN-SOON TAN2,3,5, HELEN G HEALY1,2, WENDY E HOY2,3
1Kidney Health Service, Metro North Hospital and Health Service, Brisbane, Queensland, Australia; 2CKD.QLD and the NHMRC CKD.CRE, The University of Queensland, Brisbane, Queensland, Australia; 3Faculty of Medicine, The University of Queensland, Brisbane, Queensland, Australia; 4Renal Services, Toowoomba Hospital, Toowoomba, Queensland, Australia; 5Department of Nephrology, Logan Hospital, Logan, Queensland, Australia.
Background: Higher BMI is a health risk in the general Australian population. Its pattern in CKD, taking into account the heterogeneity within the latter, remains to be reported in Australia.
Aim: We describe BMI in an Australian CKD population and evaluate the pattern of its associations with demographic and clinical variables.
Methods: A cross-sectional study was conducted in three major sites enrolling participants in the CKD.QLD registry between May 2011 and July 2015. BMI was categorized by quartiles and compared across sites. Relationships between BMI quartiles and participant demographic and clinical variables were analysed.
Results: Of the 3,382 patients (median age 68, IQR 56–76 years), the median (IQR) BMI was 29.2 kg/m2 (25.3-34.4kg/m2) at Royal Brisbane and Women’s Hospital, 30.5 kg/m2 (26.4-35.4 kg/m2) for Logan Hospital, and 30.4 (26.4-35.4kg/m2) at Toowoomba Hospital. With adjustment for site, lower age (<70 years), lower socioeconomic status and indigenous ethnicity were associated with higher BMI, while age >70 years and CKD stage 5 were associated with lower BMI. After adjustment for all these factors, the proportions of CKD patients with diabetes, diabetic nephropathy, hypertension, gout and obstructive sleep apnoea were all powerfully associated with higher BMI (p<0.001), while hypertension was less dramatically but still significantly associated (p=0.014). Notably, the proportion of CKD patients with ischaemic heart disease was not associated with higher BMI.
Conclusions: BMI in CKD in renal specialty practices in Australia was selectively associated with specific participant characteristics and particular clinical phenotypes. Within the CKD population, the strong associations of higher BMI with important co-morbidities flag major opportunities for reduction and prevention of serious obesity-related complications.