Does self-monitoring of blood glucose improve outcome in type 2 diabetes? The Fremantle Diabetes Study.
OBJECTIVE
To assess whether self-monitoring of blood glucose (SMBG) is an independent predictor of improved outcome in a community-based cohort of type 2 diabetic patients.


METHODS
We used longitudinal data from (1) 1,280 type 2 diabetic participants in the observational Fremantle Diabetes Study (FDS) who reported SMBG and diabetes treatment status at study entry (1993-1996), and (2) a subset of 531 participants who attended six or more annual assessments (referred to as the 5-year cohort). Diabetes-related morbidity, cardiac death and all-cause mortality were ascertained at each assessment, supplemented by linkage to the Western Australian Data Linkage System.


RESULTS
At baseline, 70.2% (898 out of 1,280) of type 2 patients used SMBG. During 12,491 patient-years of follow-up (mean 9.8+/-3.5 years), 486 (38.0%) type 2 participants died (196 [15.3%] from cardiac causes). SMBG was significantly less prevalent in those who died during follow-up than in those who were still alive at the end of June 2006 (65.4 vs 73.0%, p=0.005). In Cox proportional hazards modelling, after adjustment for confounding and explanatory variables, SMBG was not independently associated with all-cause mortality, but was associated with a 79% increased risk of cardiovascular mortality in patients not treated with insulin. For the 5-year cohort, time-dependent SMBG was independently associated with a 48% reduced risk of retinopathy.


CONCLUSIONS
SMBG was not independently associated with improved survival. Inconsistent findings relating to the association of SMBG with cardiac death and retinopathy may be due to confounding, incomplete covariate adjustment or chance.
Davis
W A
WA
School of Medicine and Pharmacology, University of Western Australia, Fremantle Hospital, P.O. Box 480, Fremantle, WA, 6959, Australia. wdavis@cyllene.uwa.edu.au
Bruce
D G
DG
Davis
T M E
TM
D000419:Albuminuria; D015190:Blood Glucose Self-Monitoring / Q000706:statistics & numerical data*; D015331:Cohort Studies; D003404:Creatinine / Q000652:urine; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000652:urine; D006801:Humans; D008137:Longitudinal Studies; D011237:Predictive Value of Tests; D016896:Treatment Outcome; D014904:Western Australia
D003404:Creatinine