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Health Services Research & Development

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2009 HSR&D National Meeting Abstract

National Meeting 2009

1047 — Do Changes in Population Subgroups Distort Cross-Sectional Trends in A1c as a “Quality Improvement” Measure?

Pogach LM (East Orange REAP), Miller DR (Bedford COE), Christiansen CL (Bedford COE), Fincke BG (Bedford COE), Tseng CL (East Orange REAP)

The use of < 7% A1c as a quality indicator for diabetes care in VHA is controversial. We evaluated whether serial cross-sectional changes in adherence to < 7% A1c represent improved care or population changes.

We applied HEDIS criteria to the Diabetes Epidemiologic Cohorts to identify all VHA patients with diabetes aged 18-75 years in 2001, 2003, and 2005 who were in VHA care in the prior year and had A1c measured. The last A1c was used to calculate the percent with A1c < 7%. Analyses were conducted overall, and with stratification by age ( < 65, 65-75 years), recency of diabetes onset (within year, within past 1-3 years, > 3 years ago), presence of serious comorbid conditions, and time since beginning VHA care (before 2000 or since).

The cohorts increased from 344,328 in 2001 to 691,067 in 2005. The proportion adherent to < 7% A1c increased from 43.9% in 2001 to 50.1% in 2005. There was improvement in all subgroups, but the magnitude varied. In all time periods, those with longer duration diabetes (3+ years) and without comorbid illness had “worse” results (34.7% in 2001; 43.2% in 2005), while those with recent onset of diabetes and with comorbid illness had “best” results (65.6% in 2001; 77.6% in 2005). Duration of diabetes was inversely related to percent < 7% A1c, at least up to 7 years. Except for subjects new to the VA, who declined from 25.7% to 13.6%, there was marked stability (+/- 4%) in the proportion of subgroups over time.

Overall adherence to the < 7% threshold level of glycemic control would be enhanced by an increasing proportion of subjects in subgroups for whom the outcome may have decreased benefit (older, sicker) or is easier to achieve (lesser duration), as well as appropriate intensification of treatment in healthier, younger individuals.

Aggregate cross-sectional data may result in incorrect attribution of improved care to improving trends if there are changes in population subgroups nationally or at a facility level. We suggest that reporting of subgroup distributions would provide greater transparency to stakeholders and could better prioritize quality improvement efforts.

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