Cigarette smoking and increased urine albumin excretion are interrelated predictors of nephropathy progression in type 2 diabetes.
BACKGROUND
Increased urine albumin excretion (UAE) predicts nephropathy progression in type 2 diabetes, whereas improved blood pressure (BP) control and angiotensin-converting enzyme (ACE) inhibition ameliorate both albuminuria and nephropathy progression. Cigarette smoking (CS) predicts nephropathy progression in patients with type 2 diabetes despite improved BP control and ACE inhibition. We tested the hypothesis that CS and increased UAE are interrelated predictors of nephropathy progression in patients with type 2 diabetes undergoing improved BP control and ACE inhibition.


METHODS
We prospectively followed plasma creatinine (P(cr)) levels and UAE as albumin-creatinine (alb-cr) ratio for 63.9 +/- 0.6 months in 84 patients with type 2 diabetes undergoing BP control with regimens including ACE inhibitors.


RESULTS
Despite ACE inhibition and mean BP reduction from 113.7 +/- 1.8 to 92.3 +/- 0.6 mm Hg (P < 0.001), P(cr) increased (1.03 +/- 0.02 to 1.25 +/- 0.04 mg/dL [91.1 +/- 1.8 to 110.5 +/- 3.5 micromol/L]; P < 0.001) during follow-up. Regression analysis showed that entry alb-cr ratio, but not CS, predicted nephropathy progression when considering both factors together, but CS predicted progression only when excluding alb-cr ratio. Nephropathy progression was minimal for lower levels of alb-cr ratio at entry, but increased progressively for levels greater than 300. Alb-cr ratio increment during follow-up directly correlated with nephropathy progression (r2 = 0.307; P < 0.001) and was greater in smokers than nonsmokers (1,878 +/- 346 versus 553 +/- 214; P < 0.001).


CONCLUSIONS
Data show that CS and increased UAE are interrelated predictors of nephropathy progression in patients with type 2 diabetes, and CS increases UAE in these patients despite improved BP control and ACE inhibition.
Chuahirun
Temduang
T
Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
Khanna
Apurv
A
Kimball
Kay
K
Wesson
Donald E
DE
D000328:Adult; D000419:Albuminuria / Q000097:blood / Q000209:etiology*; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use; D001794:Blood Pressure / Q000187:drug effects; D003404:Creatinine / Q000097:blood; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000188:drug therapy / Q000473:pathology* / Q000652:urine; D003928:Diabetic Nephropathies / Q000097:blood / Q000188:drug therapy / Q000209:etiology* / Q000652:urine*; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012044:Regression Analysis; D012709:Serum Albumin / Q000378:metabolism; D012907:Smoking / Q000009:adverse effects* / Q000097:blood / Q000652:urine*
D000806:Angiotensin-Converting Enzyme Inhibitors; D012709:Serum Albumin; D003404:Creatinine