Comparison of diabetes-associated secondary healthcare utilization between alternative oral antihyperglycaemic dual therapy combinations with metformin in patients with type 2 diabetes: an observational cohort study.
OBJECTIVE
To compare diabetes-associated secondary healthcare utilization in patients with type 2 diabetes (T2DM) prescribed sulphonylureas (SUs) versus other oral antihyperglycaemic agents (OHAs) as an add-on to metformin monotherapy (metformin + SU vs metformin + OHA).


METHODS
This retrospective cohort study used data from the Clinical Practice Research Datalink linked to Hospital Episode Statistics. Adults with T2DM initiated on metformin + SU or metformin + OHA from April 2003 to March 2012 were identified. Patients were matched using propensity scores. Diabetes-associated secondary healthcare visits were counted from >6 months post-initiation of dual therapy until treatment change or end of follow-up. Outcomes were calculated as rate ratios, adjusted for over-dispersion using negative binomial regression and propensity score for covariates.


RESULTS
After propensity score matching, 1704 patients were included in each cohort. For the primary objective (diabetes-associated inpatient and outpatient visits combined), the metformin + SU cohort had a directionally higher rate of diabetes-associated secondary healthcare utilization than the metformin + OHA cohort [adjusted rate ratio 1.12, 95% confidence interval (CI) 0.97-1.29]. For the secondary outcomes, the adjusted rate ratio was 1.38 (95% CI 0.95-2.00) for inpatient admissions and 1.10 (95% CI 0.95-1.28) for outpatient visits. Macrovascular complications, accounting for 77.2% of inpatient admissions, occurred at a statistically significantly higher rate in the metformin + SU cohort than in the metformin + OHA cohort (adjusted rate ratio 1.77, 95% CI 1.15-2.71).


CONCLUSIONS
This study found a statistically significant higher rate of inpatient admissions for macrovascular complications and cardiology outpatient visits and, overall, a directionally higher rate of secondary healthcare utilization for patients prescribed metformin + SU than for those prescribed metformin + OHA. This adds to the evidence that long-term and health economic outcomes should be considered in treatment decisions for patients with type 2 diabetes.
Clinical Practice Research Datalink, MHRA, London, UK.
H
H
Strongman
Merck Sharp & Dohme Ltd, Hoddesdon, UK.
K
K
D'Oca
Merck Sharp & Dohme Ltd, Hoddesdon, UK.
H
H
Langerman
Merck Sharp & Dohme Ltd, Hoddesdon, UK.
R
R
Das
D000368:Aged; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000209:etiology; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000628:therapy*; D004359:Drug Therapy, Combination / Q000379:methods; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D008297:Male; D008687:Metformin / Q000627:therapeutic use*; D008875:Middle Aged; D009819:Office Visits / Q000706:statistics & numerical data; D010342:Patient Acceptance of Health Care / Q000706:statistics & numerical data*; D010343:Patient Admission / Q000706:statistics & numerical data; D012189:Retrospective Studies; D013453:Sulfonylurea Compounds / Q000627:therapeutic use*
D007004:Hypoglycemic Agents; D013453:Sulfonylurea Compounds; D008687:Metformin
diabetes complications; macrovascular disease; metformin; pharmaco-epidemiology; sulphonylureas; type 2 diabetes