There was medical center-level variation in the percent of patients referred to a telephonic nurse management program at 12 Kaiser Permanente medical centers, allowing us to examine in a quasi-experimental design the associations between referral and outcomes.
Compared with women from centers where the annual proportion of referral nurse management was <30 % , women who delivered from centers with an annual referral proportion >70 % were less likely to have a macrosomic infant and more likely to have postpartum glucose testing (multiple-adjusted odds ratio, 0.75; 95 % confidence interval, 0.57-0.98 and multiple-adjusted odds ratio, 22.96; 95 % confidence interval, 2.56-3.42, respectively).
Receiving care at the centers with higher referral frequency to telephonic nurse management for gestational diabetes mellitus was associated with decreased risk of macrosomic infant and increased postpartum glucose testing.