title: Health care utilization and costs in type 2 diabetes mellitus and their association with renal impairment.
abstract: OBJECTIVE
  To evaluate the health economic burden of renal impairment (RI) in patients with type 2 diabetes mellitus (T2DM).
  
  
  METHODS
  This retrospective analysis used medical and pharmacy claims and outpatient laboratory data from a large US health care plan (January 1, 2004 to December 31, 2008). Patients with T2DM aged ≥ 18 years with continuous enrollment for ≥ 12 months pre- and post-index date (defined as date of first evidence of T2DM) who had ≥ 1 serum creatinine (SCr) laboratory test in pre- and post-index periods were included. Renal impairment prevalence was determined by laboratory data and compared with prevalence of RI identified from claims (physician-diagnosed). Renal impairment stages were categorized using estimated glomerular filtration rate. Multivariate analyses were conducted to examine association between pre-index RI status and post-index total diabetes-related health care costs.
  
  
  RESULTS
  Of 82 263 patients with T2DM with post-index SCr laboratory values, 34.4% had RI as evidenced by laboratory data, while 11.9% had RI using claims-based criteria. The prevalence as determined from laboratory data was roughly 3 times higher than the prevalence determined from claims data, probably due to under-recognition and under-diagnosis by providers. Compared with patients without pre-index RI, patients with RI were more likely to incur ≥ 1 diabetes-related ambulatory visit (88.8% vs 85.2%; P < 0.001), emergency room visit (7.2% vs 4.5%; P < 0.001), and inpatient stay (13.8% vs 6.6%; P < 0.001) during the 12-month post-index evaluation period. Patients with pre-index RI incurred 41.8% higher post-index total diabetes-related health care costs compared with no RI (odds ratio, 1.42 [CI, 1.29-1.56]; P < 0.001). Compared with no RI, insulin-related health care costs were independently associated with increases of 37.4% (mild RI), 166.8% (moderate RI), 408.3% (severe RI), and 343.8% (end-stage RI).
  
  
  CONCLUSIONS
  Renal impairment in T2DM is associated with high health care utilization and costs.
authors.affiliation: Health Economics and Outcomes Research, OptumInsight, Eden Prairie, MN, USA. james.burke@optum.com
authors.forename: James
authors.initials: J
authors.lastname: Burke
authors.forename: Birgit
authors.initials: B
authors.lastname: Kovacs
authors.forename: Leigh
authors.initials: L
authors.lastname: Borton
authors.forename: Stephen
authors.initials: S
authors.lastname: Sander
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000553:Ambulatory Care / Q000191:economics / Q000706:statistics & numerical data*; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000191:economics / Q000628:therapy; D004636:Emergency Service, Hospital / Q000191:economics / Q000706:statistics & numerical data*; D005260:Female; D017048:Health Care Costs; D006760:Hospitalization / Q000191:economics*; D006801:Humans; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D015995:Prevalence; D051437:Renal Insufficiency / Q000191:economics* / Q000453:epidemiology / Q000209:etiology / Q000628:therapy; D012189:Retrospective Studies; D014481:United States; D055815:Young Adult