Age as a determinant of glomerular filtration rate in non-insulin-dependent diabetes mellitus.
BACKGROUND
The level of glomerular filtration rate (GFR) and its determinants in non-insulin-dependent diabetes mellitus (NIDDM) are currently controversial.


METHODS
We measured GFR and effective renal plasma flow (ERPF) in 121 consecutive NIDDM without evidence of overt diabetic nephropathy. Age varied from 28 to 70 years, 61.2% were women and known duration of NIDDM was 0-37 years. Hypertension was detected in 36.4% of patients and 47.8% had microalbuminuria.


RESULTS
An inverse correlation was found between GFR and age, but not with known duration of NIDDM: It was a weak correlation (r = -0.41) but statistically significant (P < 0.001). The other variables considered were not significant by multiple stepwise regression analysis, but patients with lower GFR tended to have diabetic retinopathy more frequently. GFR was lower in hypertensive compared to normotensive patients (123 +/- 28.4 versus 136 +/- 32.5 ml/min/1.73 m2; P < 0.05), but was not different between patients with normal and elevated albumin excretion rate. ERPF also had an inverse correlation with age (r = -0.45, P < 0.001).


CONCLUSIONS
We conclude that (i) age should be considered as a confounding variable when evaluating GFR in patients with NIDDM, and (ii) the age-dependent decline in GFR may mask hyperfiltration in the early stages of diabetic nephropathy in NIDDM:
Rius
F
F
Endocrinology Service, Hospital Universitari 'Germans Trias i Pujol,' Universitat Autònoma de Barcelona, Spain.
Pizaro
E
E
Salinas
I
I
Lucas
A
A
Sanmarti
A
A
Romero
R
R
D000328:Adult; D000367:Age Factors; D000368:Aged; D000959:Antihypertensive Agents / Q000627:therapeutic use; D016022:Case-Control Studies; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000503:physiopathology*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000188:drug therapy / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D017596:Renal Plasma Flow, Effective
D000959:Antihypertensive Agents