Type 2 Diabetes Can Be Prevented: Why Are We Waiting?

Gregory A. Nichols, PhD


August 17, 2015

Economic Evaluation of Combined Diet and Physical Activity Promotion Programs to Prevent Type 2 Diabetes Among Persons at Increased Risk: A Systematic Review for the Community Preventive Services Task Force

Li R, Qu S, Zhang P, et al
Ann Intern Med. 2015 Jul 14. [Epub ahead of print]

Are diet and physical activity programs cost-effective in preventing diabetes? This systematic review was conducted on behalf of the Centers for Disease Control and Prevention Community Preventive Services Task Force to find out. The investigators included studies that provided information on program cost or incremental cost-effectiveness ratio (ICER), measured as dollars per life-year gained (LYG), quality-adjusted life-year (QALY) saved, or disability-adjusted life-year (DALY) averted.

To be included in the analysis, studies on program cost were required to evaluate the actual program implementation cost. Studies also had to include a population at increased risk for type 2 diabetes, based on glycemic measures or risk scores for diabetes; presence of cardiovascular disease or the metabolic syndrome; intervention with both diet and physical activity components delivered in at least two contact sessions over at least 3 months; and, for the cost-effectiveness studies, comparison with a similar population receiving either usual care or no intervention.

Group and Even Individual Programs Are a Bargain

The analysis included 28 studies. Costs were expressed in 2013 US dollars. The median program cost per participant was $653. Costs were lower for group-based programs (median, $417) and programs implemented in community or primary care settings (median, $424) than for the US DPP (Diabetes Prevention Program) trial and the DPP Outcome Study ($5881).

Twenty-two studies assessed the ICERs of the programs. From a health system perspective, 16 studies reported a median ICER of $13,761 per QALY saved. However, group-based programs were much more cost-effective (median, $1819 per QALY) compared with programs that used individual sessions (median, $15,846 per QALY).

Metformin Prescription for Insured Adults With Prediabetes From 2010 to 2012: A Retrospective Cohort Study

Moin T, Li J, Duro OK, et al
Ann Intern Med. 2015;162:542-548

Moin and colleagues used claims and laboratory and prescription data from 2010 to 2012 from UnitedHealthcare to conduct a retrospective cohort analysis of metformin prescriptions among 17,352 working-age adults with prediabetes. All participants were prediabetic at year 1, defined as having two or more ICD-9 diagnostic codes of 790.2x from an inpatient or outpatient claim; last glycated hemoglobin (A1c) level of 5.7% to 6.4%; last fasting plasma glucose (FPG) level of 100-125 mg/dL; or last 2-hour plasma glucose level of 140-199 mg/dL on an oral glucose tolerance test.

Patients with a diagnosis of diabetes in year 1 were excluded from the sample. Diabetes was defined as having one or more ICD-9 diagnostic codes of 250.xx from an inpatient or outpatient claim; an A1c level ≥ 6.5%; FPG level > 125 mg/dL or a 2-hour plasma glucose level ≥ 200 mg/dL on an oral glucose tolerance test (OGTT); or one or more prescription claims for insulin or an antihyperglycemic medication other than metformin. The primary outcome was any prescription claim for metformin in the 3-year study window that preceded a diabetes diagnosis.

Little Use of Metformin Therapy

Only 3.7% (n= 647) of patients had a prescription claim for metformin during the study. Although metformin use was higher among the subset of patients that are most indicated for treatment (BMI > 35 kg/m2 or gestational diabetes), it was still only 7.8%. Results differed depending on how prediabetes was defined, but treatment rates were low for all subjects (10.3% among those identified by ICD-9 codes, 4.9% if identified by A1c, 2.4% if found by FPG, and 14.0% if by OGTT). Female sex and an ICD-9 code for obesity increased the probability of receiving metformin, but again, treatment rates were still low for these groups (4.8% for women and 6.6% among those with an obesity diagnosis).



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