Complications of dysglycemia and medical costs associated with nondiabetic hyperglycemia.
OBJECTIVE
To estimate the prevalence of complications associated with diabetes in patients with hyperglycemia below the threshold for diabetes, and to evaluate the associated medical costs.


METHODS
Retrospective observational cohort study.


METHODS
We used fasting and random glucose test results, and a previously validated predictive equation to assign 26,111 nondiabetic patients to the following categories: normoglycemia, isolated impaired fasting glucose (I-IFG), isolated impaired glucose tolerance (I-IGT), or IFG with IGT (IFG/IGT). We identified microvascular complications (retinopathy, neuropathy, nephropathy) and macrovascular complications (cardiovascular disease, stroke, peripheral vascular disease, heart failure) commonly associated with diabetes from electronic medical records. We then calculated and compared the impacts of hyperglycemia and its complications in terms of age/sex-adjusted mean annual medical care costs.


RESULTS
Complications were most prevalent among the I-IGT and IFG/IGT patients -- more than half (51.1% in each group) had at least 1 complication compared with 33.9% of normoglycemic patients (P <.001 for both comparisons). Macrovascular complications added $3,863 (P <.0001) to annual age/sex-adjusted per-person medical costs; microvascular complications added $1,874 (P <.0001). I-IGT ($716; P <.0001) and IFG/IGT ($438; P = .009) independently added to costs after controlling for presence of any complication.


CONCLUSIONS
For many patients, complications associated with hyperglycemia appear to develop before diabetes diagnosis. Complications add significantly to the cost of medical care at hyperglycemic levels below the threshold for diabetes. However, the increased prevalence of complications did not completely explain the observed differences in age/sex-adjusted medical care costs.
Nichols
Gregory A
GA
Center for Health Research, Kaiser Permanente, Portland, OR 97227-1098, USA. greg.nichols@kpchr.org
Arondekar
Bhakti
B
Herman
William H
WH
D000367:Age Factors; D000368:Aged; D017281:Cost of Illness; D003404:Creatinine / Q000097:blood; D005215:Fasting; D005260:Female; D005919:Glomerular Filtration Rate; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000032:analysis; D017048:Health Care Costs / Q000706:statistics & numerical data*; D006279:Health Maintenance Organizations / Q000191:economics*; D006801:Humans; D006943:Hyperglycemia / Q000191:economics* / Q000453:epidemiology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009922:Oregon / Q000453:epidemiology; D011236:Prediabetic State / Q000191:economics* / Q000453:epidemiology / Q000503:physiopathology*; D015995:Prevalence; D051437:Renal Insufficiency / Q000191:economics / Q000453:epidemiology / Q000503:physiopathology; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D014652:Vascular Diseases / Q000191:economics / Q000453:epidemiology / Q000503:physiopathology
D003404:Creatinine; D006442:Glycated Hemoglobin