Blue Cross Blue Shield of Massachusetts’ Alternative Quality Contract (AQC) showed the largest gains in quality of care for members with social risk factors, according to a study by Harvard Medical School researchers published in the January issue of Health Affairs.

The study compared measures of health care quality and spending among enrollees in areas with fewer social risk factors against those with more, both before and after providers started with the insurer’s AQC, a modified global payment model designed to encourage cost-effective, patient-centered care by paying participating physicians and hospitals for the quality, not the quantity, of the services they deliver. The researchers found similar spending levels for patients in areas with low and high socioeconomic status (SES) before and after physicians entered the AQC. But quality improvements were more pronounced in areas with low SES.

The AQC now covers 90% of physicians and hospitals in the Blues’ HMO network, and the insurer last January expanded the contract to five Massachusetts physician and hospital organizations that provide care to PPO members.

The researchers reviewed 18 ambulatory process measures for chronic disease management and adult and pediatric preventive and wellness care; five outcomes measures for diabetes, cholesterol and blood pressure; and spending across both the insurer and patient cost sharing.

“Unadjusted aggregate process measures improved more among AQC enrollees in the subgroup of lower socioeconomic status than among enrollees in the higher-status subgroup during the four years, narrowing the difference between these subgroups,” the researchers reported. Process measures improved on average 1.2 percentage points per year from 2009 to 2012 (the intervention years). There was no statistically significant change in process measures for the pre-intervention period. Meanwhile, outcomes measures showed continuous improvement among both low-SES and high-SES groups during the intervention period.

“The fact that disparities between enrollees in areas with lower and higher socioeconomic status narrowed among process measures but not for outcome measures, despite larger improvements for both subgroups in outcome measures, could reflect a weak relationship between process and outcome measures,” the researchers said. For example, just because a provider monitors hemoglobin A1c in patients with diabetes (a process measure) doesn’t mean the actual hemoglobin A1c level (an outcome measure) will drop. “In general, improvement in outcome measures is considered more complex and challenging because it requires patient adherence and changes in health behaviors, which are less under the direct influence of providers than process measures are. The fact that outcomes improved substantially for AQC enrollees of both lower and higher socioeconomic status is meaningful.”

Michael Chernew, one of the study authors, said, “There is a legitimate concern that disadvantaged populations could suffer under new payment models. These results allay, but do not eliminate, those concerns. The details of each payment program will matter, so continued evaluation is important.”

To view the study abstract, visit