Proteinuria is a determinant of quality of life in diabetic nephropathy: modeling lagged effects with path analysis.
BACKGROUND
Diabetic nephropathy with overt proteinuria often progresses relentlessly to end-stage renal disease (ESRD).


METHODS
To answer the question whether it is impaired glomerular filtration rate (GFR) or its precursor proteinuria which is more related with multiple domains of health-related quality of life (HRQOL), we measured GFR and proteinuria in 44 patients with type 2 diabetes and overt nephropathy and repeated the measurements after 4 months. 38 patients with ESRD due to diabetic nephropathy served as a control group. We used path analysis to examine the association of baseline proteinuria and GFR with baseline and subsequent HRQOL scales.


RESULTS
Compared to patients with ESRD, patients with non-dialysis CKD had Kidney Disease Burden (KDB) that was, on a scale from 0 to 100, 19.8 better (95% CI 6.9-32.8) (p = 0.003). Mental component score (MCS) did not differ and physical component score (PCS) was worse in non-dialysis CKD patients by 8.5 (p < 0.001). Proteinuria at baseline was a predictor of PCS, MCS and KDB score at 4 months, suggesting a lagged effect of proteinuria on HRQOL after controlling for the autoregressive effects. GFR was not shown to have a significant impact on HRQOL. One log unit increase in proteinuria was associated with 3.8 (p = 0.011) fall in PCS, 3.3 (p = 0.043) fall in MCS and 10.6 (p = 0.006) fall in KDB.


CONCLUSIONS
In patients with advanced diabetic nephropathy, we found that proteinuria has a lagged and profound effect on multiple domains of HRQOL.
Kelley
Ken
K
Inquiry Methodology Program, Indiana University, Bloomington, Ind., USA.
Aricak
O Tolga
OT
Light
Robert P
RP
Agarwal
Rajiv
R
D000368:Aged; D017281:Cost of Illness; D003924:Diabetes Mellitus, Type 2; D003928:Diabetic Nephropathies / Q000150:complications* / Q000503:physiopathology*; D005260:Female; D005919:Glomerular Filtration Rate; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D011507:Proteinuria / Q000209:etiology*; D011788:Quality of Life